Non- Surgical Strabismus management

GGroup roup Pediatric ophthalmology amp StrabismusPediatric ophthalmology amp StrabismusMashhad Eye Research Center

Mashhad University of Medical SciencesEye Hospital Khatam

When it comes to treating the patient with strabismus many ophthalmologists think of surgery first but there are several instances where the non-surgical method is

best

What is the prescription aim

Our purpose is best visual acuity in distance versus binocular alignment

Certainly we want to eliminate any amblyogenic factors by using the optical correction and consider the binocular status

Prescribing for Children

bull In adults the correction of refractive errors has one measurable endpoint the best corrected visual acuity

bull Prescribing visual correction for children often has two goals

1- providing a focused retinal image2- achieving the optimal balance between

accommodation and convergence

spectacleCreate sharp retinal image that improve

fusionAssist balance between accomodation

and convergenceTrend is prescribe full amount of

refractive error in cycloplagiaYoung children normally accept the

correct glass

General Rules

Search for hurt behind nose or pinch the nose or uncomfortable frame

Atropinization of both eyes for 3 to 4 days in case with unable to relax accomodation

Explain indication in the presence of normal vision(refractive accomodative ET)

Consider full corection from infancy through pre school age

spectacle

Consider prescibe BCVA in old children

Hypermetropic correction greater than +2 in esotropic patient

spectacle

case1

5 years old girl referred to clinic for strabismusVision BCVA OD2020OS2030RefractionOD+1 sphos+2 sphEOM10ET with glass(far)30ET with glass(near)Fundus normal

What is your plan

Glass BifocalValuable in high ACA ratio accomodative ETRestricted in whom that were orthotropic or

small angle ET in far by FCR but residual ET at near that convert to orthotropia or esophoria by additional plus lens

Contraindication is amblyopia and not complete elimination of ET in near

Start with +1 sph and increase power in step of +05 up to +3 sph

Minimal power that convert ET to E prescribed(prevent excessive relaxation of accommodation)

Success depend on proper bifocal segmentPrefer straight top segment which bisect pupil

or touch lower border in straight head position

Glass Bifocal

Progressive as a substitute Fusional amplitude increase so reduce power

stepwise until discontinueIf still depend to maintain fusion during teenage

year consider surgeryFCR must be done semiannually and correction

readjustedGoal is maximal hyperopic correction but

reduce bifocal power by same amount if additional plus is necessary

Glass Bifocal

High ACA Ratio

Any uncorrected hyperopic refractive error will trigger convergenece therefore 050 D should be full corrected

It may be possible to avoid bifocal by simply slightly overplussing the patient with a single vision correction ( +050 +075D )

Bifocal strength +2 +35 D Bifocal are often eliminated in the teenage

years

6years old boy referred to strabismus clinic due to deviationparents notice occasional outward deviation of eyes especially after awakening

Vision1010 (ou) Refraction-100 (ou) EOM15 prism diopter X(near)25 prism diopter XT(far) Fundusnormal What is your plan

case2

Refractive Errors

bull Unequal clarity in vision represents an obstacle to fusion and can facilitate suppression contributing to progressive loss of control in X(T)

bull Significant RE especially astigmatism and anisometropia need to be corrected

bull All patients in minus lenses should be seen within 3 to 4 weeks after starting the therapy

bull Minus lenses should be discontinued if esotropia develops

bull There are studies that suggest that this treatment may induce myopia

bull As the child grows older asthenopic symptoms with over-minus lenses become prominent as the amount of near work increases

bull Part time patching of the non-deviating eye for four to six hours daily may convert an intermittent exotropia to a phoria

bull Although the benefit is usually temporary occlusion can be used to postpone surgical intervention in responsive patients

bull Alternate occlusion may be used in patients with equal fixation preferences

bull Initially the results are evaluated after 4 months of occlusionbull If the angle of deviation is decreased the occlusion should be

continued and assessment made every 4 months until no further change occurs

bull In case there is no improvement for 4 months it is discontinued

Occlusion

Various Non-Surgical Therapies for Intermittent Exotropia

Indications for Surgery

The AAO PPP pediatric glass prescribing guideline

bull When hyperopia and esotropia coexist initial management includes full correction of the cycloplegic refractive error

bull Later reductions in the amount of correction may be appropriate based on the amount of esotropia and level of stereopsis at near and at distance with the full cycloplegic correction in place

Hyperopia associated with partly

of full accommodative esotropia

When hyperopia is associated with overt esotropia or ever large esophoria a full cycloplegic correction should be prescribed

The principle is to prescribed the maximum plus the patient will accept without degrading the visual acuity

Generally this equals the full cyclopentolate or atropine refration upto the age 2 years because the patients enviroment is close at hand and subjective tests are not possible

In older children 050 ndash 100 D should be subtracted In some cases of acc ET an extra + 050 D could

make some difference to the strabismus

Undercorrection amp Undercorrection amp overcorrectionovercorrection

Undercorrect myopia in accommodative ET rarely tolerated

Slight overcorrection of myopia in IXTOptical overcorrection or under

correction in treatment of amblyopia(penalization)

تاری ساله اي با شكايت 60خانم دید و دو بینی در نگاه نزدیک علیرغم

استفاده از عینک نزدیک مراجعه کرده است قدرت و ساخت عینک نزدیک

ایرادی ندارد در روبرو و دور ارتو است

ر اه حل پیشنهادی شما چیست

ساله ای با انحراف چشم و دو بینی از 33بیمار هفته قبل مراجعه کرده است 2

Ophthalmic Prism

Ali Akbar SabermoghaddamAssociated professor of OphthalmologyEye research center amp Khatam eye hospital MUMS

Prisms bend rays toward the base

PRISMS

P

cm displacement

1 m=

Prismatic Power (P)

apex

base

100 cm

X cm

Ophthalmic PrismPrismatic power

Ophthalmic Prism

bull Prisms function by bending rays of light towards the base of the prism bull The degree of bending of light depends upon the angle of incidence of light and the prismatic power

Ophthalmic prisms have been used in the treatment of binocular problems for more than 100 years

Ophthalmic Prism

Corrective Prism1 Ground ndash In Prism2 Fresnel ndash On Prism (Press-on Prisms)

Ophthalmic PrismPRESCRIBING INDUCED PRISM BY INTENTIONALLY

DISPLACING THE OPTICAL CENTERS Light traveling through the optical center of a lens encounters

no prismatic power and passes through undeviated However as the distance from the optical center increases

increasing prismatic power is encountered Prentices rule This is defined algebraically using the formula Δ = hD where Δ = prism diopters h = distance from the

optical center in centimeters and D= power of the lens in diopters

Of note the direction of displacement of light depends on whether the lens is of minus or plus power

- Minus lenses function as prisms held apex to apex that is as if the apex

of the prism were at the optical center of the lens - In other words a ray of light traveling above the optical

center encounters base-up prism power and a ray traveling below

the optical center encounters base-down prism

In the mid 1960s the 150-year-old Fresnel principle was applied to ophthalmic prisms for the first time The first ophthalmic Fresnel prism known as the wafer prism was molded of an acrylic resin making it much lighter and thinner than the corresponding powers of conventional prisms thus extending the useful range of prism powers

In 1970 the Press-OnTM prism a Fresnel-principle prism molded in flexible plastic was introduced to ophthalmologists This thin light membrane prism had the advantage of conforming and adhering to a smooth surface and thus could be affixed directly to a plano or basecurved correcting spectacle lens

Ophthalmic Prism

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

When it comes to treating the patient with strabismus many ophthalmologists think of surgery first but there are several instances where the non-surgical method is

best

What is the prescription aim

Our purpose is best visual acuity in distance versus binocular alignment

Certainly we want to eliminate any amblyogenic factors by using the optical correction and consider the binocular status

Prescribing for Children

bull In adults the correction of refractive errors has one measurable endpoint the best corrected visual acuity

bull Prescribing visual correction for children often has two goals

1- providing a focused retinal image2- achieving the optimal balance between

accommodation and convergence

spectacleCreate sharp retinal image that improve

fusionAssist balance between accomodation

and convergenceTrend is prescribe full amount of

refractive error in cycloplagiaYoung children normally accept the

correct glass

General Rules

Search for hurt behind nose or pinch the nose or uncomfortable frame

Atropinization of both eyes for 3 to 4 days in case with unable to relax accomodation

Explain indication in the presence of normal vision(refractive accomodative ET)

Consider full corection from infancy through pre school age

spectacle

Consider prescibe BCVA in old children

Hypermetropic correction greater than +2 in esotropic patient

spectacle

case1

5 years old girl referred to clinic for strabismusVision BCVA OD2020OS2030RefractionOD+1 sphos+2 sphEOM10ET with glass(far)30ET with glass(near)Fundus normal

What is your plan

Glass BifocalValuable in high ACA ratio accomodative ETRestricted in whom that were orthotropic or

small angle ET in far by FCR but residual ET at near that convert to orthotropia or esophoria by additional plus lens

Contraindication is amblyopia and not complete elimination of ET in near

Start with +1 sph and increase power in step of +05 up to +3 sph

Minimal power that convert ET to E prescribed(prevent excessive relaxation of accommodation)

Success depend on proper bifocal segmentPrefer straight top segment which bisect pupil

or touch lower border in straight head position

Glass Bifocal

Progressive as a substitute Fusional amplitude increase so reduce power

stepwise until discontinueIf still depend to maintain fusion during teenage

year consider surgeryFCR must be done semiannually and correction

readjustedGoal is maximal hyperopic correction but

reduce bifocal power by same amount if additional plus is necessary

Glass Bifocal

High ACA Ratio

Any uncorrected hyperopic refractive error will trigger convergenece therefore 050 D should be full corrected

It may be possible to avoid bifocal by simply slightly overplussing the patient with a single vision correction ( +050 +075D )

Bifocal strength +2 +35 D Bifocal are often eliminated in the teenage

years

6years old boy referred to strabismus clinic due to deviationparents notice occasional outward deviation of eyes especially after awakening

Vision1010 (ou) Refraction-100 (ou) EOM15 prism diopter X(near)25 prism diopter XT(far) Fundusnormal What is your plan

case2

Refractive Errors

bull Unequal clarity in vision represents an obstacle to fusion and can facilitate suppression contributing to progressive loss of control in X(T)

bull Significant RE especially astigmatism and anisometropia need to be corrected

bull All patients in minus lenses should be seen within 3 to 4 weeks after starting the therapy

bull Minus lenses should be discontinued if esotropia develops

bull There are studies that suggest that this treatment may induce myopia

bull As the child grows older asthenopic symptoms with over-minus lenses become prominent as the amount of near work increases

bull Part time patching of the non-deviating eye for four to six hours daily may convert an intermittent exotropia to a phoria

bull Although the benefit is usually temporary occlusion can be used to postpone surgical intervention in responsive patients

bull Alternate occlusion may be used in patients with equal fixation preferences

bull Initially the results are evaluated after 4 months of occlusionbull If the angle of deviation is decreased the occlusion should be

continued and assessment made every 4 months until no further change occurs

bull In case there is no improvement for 4 months it is discontinued

Occlusion

Various Non-Surgical Therapies for Intermittent Exotropia

Indications for Surgery

The AAO PPP pediatric glass prescribing guideline

bull When hyperopia and esotropia coexist initial management includes full correction of the cycloplegic refractive error

bull Later reductions in the amount of correction may be appropriate based on the amount of esotropia and level of stereopsis at near and at distance with the full cycloplegic correction in place

Hyperopia associated with partly

of full accommodative esotropia

When hyperopia is associated with overt esotropia or ever large esophoria a full cycloplegic correction should be prescribed

The principle is to prescribed the maximum plus the patient will accept without degrading the visual acuity

Generally this equals the full cyclopentolate or atropine refration upto the age 2 years because the patients enviroment is close at hand and subjective tests are not possible

In older children 050 ndash 100 D should be subtracted In some cases of acc ET an extra + 050 D could

make some difference to the strabismus

Undercorrection amp Undercorrection amp overcorrectionovercorrection

Undercorrect myopia in accommodative ET rarely tolerated

Slight overcorrection of myopia in IXTOptical overcorrection or under

correction in treatment of amblyopia(penalization)

تاری ساله اي با شكايت 60خانم دید و دو بینی در نگاه نزدیک علیرغم

استفاده از عینک نزدیک مراجعه کرده است قدرت و ساخت عینک نزدیک

ایرادی ندارد در روبرو و دور ارتو است

ر اه حل پیشنهادی شما چیست

ساله ای با انحراف چشم و دو بینی از 33بیمار هفته قبل مراجعه کرده است 2

Ophthalmic Prism

Ali Akbar SabermoghaddamAssociated professor of OphthalmologyEye research center amp Khatam eye hospital MUMS

Prisms bend rays toward the base

PRISMS

P

cm displacement

1 m=

Prismatic Power (P)

apex

base

100 cm

X cm

Ophthalmic PrismPrismatic power

Ophthalmic Prism

bull Prisms function by bending rays of light towards the base of the prism bull The degree of bending of light depends upon the angle of incidence of light and the prismatic power

Ophthalmic prisms have been used in the treatment of binocular problems for more than 100 years

Ophthalmic Prism

Corrective Prism1 Ground ndash In Prism2 Fresnel ndash On Prism (Press-on Prisms)

Ophthalmic PrismPRESCRIBING INDUCED PRISM BY INTENTIONALLY

DISPLACING THE OPTICAL CENTERS Light traveling through the optical center of a lens encounters

no prismatic power and passes through undeviated However as the distance from the optical center increases

increasing prismatic power is encountered Prentices rule This is defined algebraically using the formula Δ = hD where Δ = prism diopters h = distance from the

optical center in centimeters and D= power of the lens in diopters

Of note the direction of displacement of light depends on whether the lens is of minus or plus power

- Minus lenses function as prisms held apex to apex that is as if the apex

of the prism were at the optical center of the lens - In other words a ray of light traveling above the optical

center encounters base-up prism power and a ray traveling below

the optical center encounters base-down prism

In the mid 1960s the 150-year-old Fresnel principle was applied to ophthalmic prisms for the first time The first ophthalmic Fresnel prism known as the wafer prism was molded of an acrylic resin making it much lighter and thinner than the corresponding powers of conventional prisms thus extending the useful range of prism powers

In 1970 the Press-OnTM prism a Fresnel-principle prism molded in flexible plastic was introduced to ophthalmologists This thin light membrane prism had the advantage of conforming and adhering to a smooth surface and thus could be affixed directly to a plano or basecurved correcting spectacle lens

Ophthalmic Prism

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

What is the prescription aim

Our purpose is best visual acuity in distance versus binocular alignment

Certainly we want to eliminate any amblyogenic factors by using the optical correction and consider the binocular status

Prescribing for Children

bull In adults the correction of refractive errors has one measurable endpoint the best corrected visual acuity

bull Prescribing visual correction for children often has two goals

1- providing a focused retinal image2- achieving the optimal balance between

accommodation and convergence

spectacleCreate sharp retinal image that improve

fusionAssist balance between accomodation

and convergenceTrend is prescribe full amount of

refractive error in cycloplagiaYoung children normally accept the

correct glass

General Rules

Search for hurt behind nose or pinch the nose or uncomfortable frame

Atropinization of both eyes for 3 to 4 days in case with unable to relax accomodation

Explain indication in the presence of normal vision(refractive accomodative ET)

Consider full corection from infancy through pre school age

spectacle

Consider prescibe BCVA in old children

Hypermetropic correction greater than +2 in esotropic patient

spectacle

case1

5 years old girl referred to clinic for strabismusVision BCVA OD2020OS2030RefractionOD+1 sphos+2 sphEOM10ET with glass(far)30ET with glass(near)Fundus normal

What is your plan

Glass BifocalValuable in high ACA ratio accomodative ETRestricted in whom that were orthotropic or

small angle ET in far by FCR but residual ET at near that convert to orthotropia or esophoria by additional plus lens

Contraindication is amblyopia and not complete elimination of ET in near

Start with +1 sph and increase power in step of +05 up to +3 sph

Minimal power that convert ET to E prescribed(prevent excessive relaxation of accommodation)

Success depend on proper bifocal segmentPrefer straight top segment which bisect pupil

or touch lower border in straight head position

Glass Bifocal

Progressive as a substitute Fusional amplitude increase so reduce power

stepwise until discontinueIf still depend to maintain fusion during teenage

year consider surgeryFCR must be done semiannually and correction

readjustedGoal is maximal hyperopic correction but

reduce bifocal power by same amount if additional plus is necessary

Glass Bifocal

High ACA Ratio

Any uncorrected hyperopic refractive error will trigger convergenece therefore 050 D should be full corrected

It may be possible to avoid bifocal by simply slightly overplussing the patient with a single vision correction ( +050 +075D )

Bifocal strength +2 +35 D Bifocal are often eliminated in the teenage

years

6years old boy referred to strabismus clinic due to deviationparents notice occasional outward deviation of eyes especially after awakening

Vision1010 (ou) Refraction-100 (ou) EOM15 prism diopter X(near)25 prism diopter XT(far) Fundusnormal What is your plan

case2

Refractive Errors

bull Unequal clarity in vision represents an obstacle to fusion and can facilitate suppression contributing to progressive loss of control in X(T)

bull Significant RE especially astigmatism and anisometropia need to be corrected

bull All patients in minus lenses should be seen within 3 to 4 weeks after starting the therapy

bull Minus lenses should be discontinued if esotropia develops

bull There are studies that suggest that this treatment may induce myopia

bull As the child grows older asthenopic symptoms with over-minus lenses become prominent as the amount of near work increases

bull Part time patching of the non-deviating eye for four to six hours daily may convert an intermittent exotropia to a phoria

bull Although the benefit is usually temporary occlusion can be used to postpone surgical intervention in responsive patients

bull Alternate occlusion may be used in patients with equal fixation preferences

bull Initially the results are evaluated after 4 months of occlusionbull If the angle of deviation is decreased the occlusion should be

continued and assessment made every 4 months until no further change occurs

bull In case there is no improvement for 4 months it is discontinued

Occlusion

Various Non-Surgical Therapies for Intermittent Exotropia

Indications for Surgery

The AAO PPP pediatric glass prescribing guideline

bull When hyperopia and esotropia coexist initial management includes full correction of the cycloplegic refractive error

bull Later reductions in the amount of correction may be appropriate based on the amount of esotropia and level of stereopsis at near and at distance with the full cycloplegic correction in place

Hyperopia associated with partly

of full accommodative esotropia

When hyperopia is associated with overt esotropia or ever large esophoria a full cycloplegic correction should be prescribed

The principle is to prescribed the maximum plus the patient will accept without degrading the visual acuity

Generally this equals the full cyclopentolate or atropine refration upto the age 2 years because the patients enviroment is close at hand and subjective tests are not possible

In older children 050 ndash 100 D should be subtracted In some cases of acc ET an extra + 050 D could

make some difference to the strabismus

Undercorrection amp Undercorrection amp overcorrectionovercorrection

Undercorrect myopia in accommodative ET rarely tolerated

Slight overcorrection of myopia in IXTOptical overcorrection or under

correction in treatment of amblyopia(penalization)

تاری ساله اي با شكايت 60خانم دید و دو بینی در نگاه نزدیک علیرغم

استفاده از عینک نزدیک مراجعه کرده است قدرت و ساخت عینک نزدیک

ایرادی ندارد در روبرو و دور ارتو است

ر اه حل پیشنهادی شما چیست

ساله ای با انحراف چشم و دو بینی از 33بیمار هفته قبل مراجعه کرده است 2

Ophthalmic Prism

Ali Akbar SabermoghaddamAssociated professor of OphthalmologyEye research center amp Khatam eye hospital MUMS

Prisms bend rays toward the base

PRISMS

P

cm displacement

1 m=

Prismatic Power (P)

apex

base

100 cm

X cm

Ophthalmic PrismPrismatic power

Ophthalmic Prism

bull Prisms function by bending rays of light towards the base of the prism bull The degree of bending of light depends upon the angle of incidence of light and the prismatic power

Ophthalmic prisms have been used in the treatment of binocular problems for more than 100 years

Ophthalmic Prism

Corrective Prism1 Ground ndash In Prism2 Fresnel ndash On Prism (Press-on Prisms)

Ophthalmic PrismPRESCRIBING INDUCED PRISM BY INTENTIONALLY

DISPLACING THE OPTICAL CENTERS Light traveling through the optical center of a lens encounters

no prismatic power and passes through undeviated However as the distance from the optical center increases

increasing prismatic power is encountered Prentices rule This is defined algebraically using the formula Δ = hD where Δ = prism diopters h = distance from the

optical center in centimeters and D= power of the lens in diopters

Of note the direction of displacement of light depends on whether the lens is of minus or plus power

- Minus lenses function as prisms held apex to apex that is as if the apex

of the prism were at the optical center of the lens - In other words a ray of light traveling above the optical

center encounters base-up prism power and a ray traveling below

the optical center encounters base-down prism

In the mid 1960s the 150-year-old Fresnel principle was applied to ophthalmic prisms for the first time The first ophthalmic Fresnel prism known as the wafer prism was molded of an acrylic resin making it much lighter and thinner than the corresponding powers of conventional prisms thus extending the useful range of prism powers

In 1970 the Press-OnTM prism a Fresnel-principle prism molded in flexible plastic was introduced to ophthalmologists This thin light membrane prism had the advantage of conforming and adhering to a smooth surface and thus could be affixed directly to a plano or basecurved correcting spectacle lens

Ophthalmic Prism

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Prescribing for Children

bull In adults the correction of refractive errors has one measurable endpoint the best corrected visual acuity

bull Prescribing visual correction for children often has two goals

1- providing a focused retinal image2- achieving the optimal balance between

accommodation and convergence

spectacleCreate sharp retinal image that improve

fusionAssist balance between accomodation

and convergenceTrend is prescribe full amount of

refractive error in cycloplagiaYoung children normally accept the

correct glass

General Rules

Search for hurt behind nose or pinch the nose or uncomfortable frame

Atropinization of both eyes for 3 to 4 days in case with unable to relax accomodation

Explain indication in the presence of normal vision(refractive accomodative ET)

Consider full corection from infancy through pre school age

spectacle

Consider prescibe BCVA in old children

Hypermetropic correction greater than +2 in esotropic patient

spectacle

case1

5 years old girl referred to clinic for strabismusVision BCVA OD2020OS2030RefractionOD+1 sphos+2 sphEOM10ET with glass(far)30ET with glass(near)Fundus normal

What is your plan

Glass BifocalValuable in high ACA ratio accomodative ETRestricted in whom that were orthotropic or

small angle ET in far by FCR but residual ET at near that convert to orthotropia or esophoria by additional plus lens

Contraindication is amblyopia and not complete elimination of ET in near

Start with +1 sph and increase power in step of +05 up to +3 sph

Minimal power that convert ET to E prescribed(prevent excessive relaxation of accommodation)

Success depend on proper bifocal segmentPrefer straight top segment which bisect pupil

or touch lower border in straight head position

Glass Bifocal

Progressive as a substitute Fusional amplitude increase so reduce power

stepwise until discontinueIf still depend to maintain fusion during teenage

year consider surgeryFCR must be done semiannually and correction

readjustedGoal is maximal hyperopic correction but

reduce bifocal power by same amount if additional plus is necessary

Glass Bifocal

High ACA Ratio

Any uncorrected hyperopic refractive error will trigger convergenece therefore 050 D should be full corrected

It may be possible to avoid bifocal by simply slightly overplussing the patient with a single vision correction ( +050 +075D )

Bifocal strength +2 +35 D Bifocal are often eliminated in the teenage

years

6years old boy referred to strabismus clinic due to deviationparents notice occasional outward deviation of eyes especially after awakening

Vision1010 (ou) Refraction-100 (ou) EOM15 prism diopter X(near)25 prism diopter XT(far) Fundusnormal What is your plan

case2

Refractive Errors

bull Unequal clarity in vision represents an obstacle to fusion and can facilitate suppression contributing to progressive loss of control in X(T)

bull Significant RE especially astigmatism and anisometropia need to be corrected

bull All patients in minus lenses should be seen within 3 to 4 weeks after starting the therapy

bull Minus lenses should be discontinued if esotropia develops

bull There are studies that suggest that this treatment may induce myopia

bull As the child grows older asthenopic symptoms with over-minus lenses become prominent as the amount of near work increases

bull Part time patching of the non-deviating eye for four to six hours daily may convert an intermittent exotropia to a phoria

bull Although the benefit is usually temporary occlusion can be used to postpone surgical intervention in responsive patients

bull Alternate occlusion may be used in patients with equal fixation preferences

bull Initially the results are evaluated after 4 months of occlusionbull If the angle of deviation is decreased the occlusion should be

continued and assessment made every 4 months until no further change occurs

bull In case there is no improvement for 4 months it is discontinued

Occlusion

Various Non-Surgical Therapies for Intermittent Exotropia

Indications for Surgery

The AAO PPP pediatric glass prescribing guideline

bull When hyperopia and esotropia coexist initial management includes full correction of the cycloplegic refractive error

bull Later reductions in the amount of correction may be appropriate based on the amount of esotropia and level of stereopsis at near and at distance with the full cycloplegic correction in place

Hyperopia associated with partly

of full accommodative esotropia

When hyperopia is associated with overt esotropia or ever large esophoria a full cycloplegic correction should be prescribed

The principle is to prescribed the maximum plus the patient will accept without degrading the visual acuity

Generally this equals the full cyclopentolate or atropine refration upto the age 2 years because the patients enviroment is close at hand and subjective tests are not possible

In older children 050 ndash 100 D should be subtracted In some cases of acc ET an extra + 050 D could

make some difference to the strabismus

Undercorrection amp Undercorrection amp overcorrectionovercorrection

Undercorrect myopia in accommodative ET rarely tolerated

Slight overcorrection of myopia in IXTOptical overcorrection or under

correction in treatment of amblyopia(penalization)

تاری ساله اي با شكايت 60خانم دید و دو بینی در نگاه نزدیک علیرغم

استفاده از عینک نزدیک مراجعه کرده است قدرت و ساخت عینک نزدیک

ایرادی ندارد در روبرو و دور ارتو است

ر اه حل پیشنهادی شما چیست

ساله ای با انحراف چشم و دو بینی از 33بیمار هفته قبل مراجعه کرده است 2

Ophthalmic Prism

Ali Akbar SabermoghaddamAssociated professor of OphthalmologyEye research center amp Khatam eye hospital MUMS

Prisms bend rays toward the base

PRISMS

P

cm displacement

1 m=

Prismatic Power (P)

apex

base

100 cm

X cm

Ophthalmic PrismPrismatic power

Ophthalmic Prism

bull Prisms function by bending rays of light towards the base of the prism bull The degree of bending of light depends upon the angle of incidence of light and the prismatic power

Ophthalmic prisms have been used in the treatment of binocular problems for more than 100 years

Ophthalmic Prism

Corrective Prism1 Ground ndash In Prism2 Fresnel ndash On Prism (Press-on Prisms)

Ophthalmic PrismPRESCRIBING INDUCED PRISM BY INTENTIONALLY

DISPLACING THE OPTICAL CENTERS Light traveling through the optical center of a lens encounters

no prismatic power and passes through undeviated However as the distance from the optical center increases

increasing prismatic power is encountered Prentices rule This is defined algebraically using the formula Δ = hD where Δ = prism diopters h = distance from the

optical center in centimeters and D= power of the lens in diopters

Of note the direction of displacement of light depends on whether the lens is of minus or plus power

- Minus lenses function as prisms held apex to apex that is as if the apex

of the prism were at the optical center of the lens - In other words a ray of light traveling above the optical

center encounters base-up prism power and a ray traveling below

the optical center encounters base-down prism

In the mid 1960s the 150-year-old Fresnel principle was applied to ophthalmic prisms for the first time The first ophthalmic Fresnel prism known as the wafer prism was molded of an acrylic resin making it much lighter and thinner than the corresponding powers of conventional prisms thus extending the useful range of prism powers

In 1970 the Press-OnTM prism a Fresnel-principle prism molded in flexible plastic was introduced to ophthalmologists This thin light membrane prism had the advantage of conforming and adhering to a smooth surface and thus could be affixed directly to a plano or basecurved correcting spectacle lens

Ophthalmic Prism

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

spectacleCreate sharp retinal image that improve

fusionAssist balance between accomodation

and convergenceTrend is prescribe full amount of

refractive error in cycloplagiaYoung children normally accept the

correct glass

General Rules

Search for hurt behind nose or pinch the nose or uncomfortable frame

Atropinization of both eyes for 3 to 4 days in case with unable to relax accomodation

Explain indication in the presence of normal vision(refractive accomodative ET)

Consider full corection from infancy through pre school age

spectacle

Consider prescibe BCVA in old children

Hypermetropic correction greater than +2 in esotropic patient

spectacle

case1

5 years old girl referred to clinic for strabismusVision BCVA OD2020OS2030RefractionOD+1 sphos+2 sphEOM10ET with glass(far)30ET with glass(near)Fundus normal

What is your plan

Glass BifocalValuable in high ACA ratio accomodative ETRestricted in whom that were orthotropic or

small angle ET in far by FCR but residual ET at near that convert to orthotropia or esophoria by additional plus lens

Contraindication is amblyopia and not complete elimination of ET in near

Start with +1 sph and increase power in step of +05 up to +3 sph

Minimal power that convert ET to E prescribed(prevent excessive relaxation of accommodation)

Success depend on proper bifocal segmentPrefer straight top segment which bisect pupil

or touch lower border in straight head position

Glass Bifocal

Progressive as a substitute Fusional amplitude increase so reduce power

stepwise until discontinueIf still depend to maintain fusion during teenage

year consider surgeryFCR must be done semiannually and correction

readjustedGoal is maximal hyperopic correction but

reduce bifocal power by same amount if additional plus is necessary

Glass Bifocal

High ACA Ratio

Any uncorrected hyperopic refractive error will trigger convergenece therefore 050 D should be full corrected

It may be possible to avoid bifocal by simply slightly overplussing the patient with a single vision correction ( +050 +075D )

Bifocal strength +2 +35 D Bifocal are often eliminated in the teenage

years

6years old boy referred to strabismus clinic due to deviationparents notice occasional outward deviation of eyes especially after awakening

Vision1010 (ou) Refraction-100 (ou) EOM15 prism diopter X(near)25 prism diopter XT(far) Fundusnormal What is your plan

case2

Refractive Errors

bull Unequal clarity in vision represents an obstacle to fusion and can facilitate suppression contributing to progressive loss of control in X(T)

bull Significant RE especially astigmatism and anisometropia need to be corrected

bull All patients in minus lenses should be seen within 3 to 4 weeks after starting the therapy

bull Minus lenses should be discontinued if esotropia develops

bull There are studies that suggest that this treatment may induce myopia

bull As the child grows older asthenopic symptoms with over-minus lenses become prominent as the amount of near work increases

bull Part time patching of the non-deviating eye for four to six hours daily may convert an intermittent exotropia to a phoria

bull Although the benefit is usually temporary occlusion can be used to postpone surgical intervention in responsive patients

bull Alternate occlusion may be used in patients with equal fixation preferences

bull Initially the results are evaluated after 4 months of occlusionbull If the angle of deviation is decreased the occlusion should be

continued and assessment made every 4 months until no further change occurs

bull In case there is no improvement for 4 months it is discontinued

Occlusion

Various Non-Surgical Therapies for Intermittent Exotropia

Indications for Surgery

The AAO PPP pediatric glass prescribing guideline

bull When hyperopia and esotropia coexist initial management includes full correction of the cycloplegic refractive error

bull Later reductions in the amount of correction may be appropriate based on the amount of esotropia and level of stereopsis at near and at distance with the full cycloplegic correction in place

Hyperopia associated with partly

of full accommodative esotropia

When hyperopia is associated with overt esotropia or ever large esophoria a full cycloplegic correction should be prescribed

The principle is to prescribed the maximum plus the patient will accept without degrading the visual acuity

Generally this equals the full cyclopentolate or atropine refration upto the age 2 years because the patients enviroment is close at hand and subjective tests are not possible

In older children 050 ndash 100 D should be subtracted In some cases of acc ET an extra + 050 D could

make some difference to the strabismus

Undercorrection amp Undercorrection amp overcorrectionovercorrection

Undercorrect myopia in accommodative ET rarely tolerated

Slight overcorrection of myopia in IXTOptical overcorrection or under

correction in treatment of amblyopia(penalization)

تاری ساله اي با شكايت 60خانم دید و دو بینی در نگاه نزدیک علیرغم

استفاده از عینک نزدیک مراجعه کرده است قدرت و ساخت عینک نزدیک

ایرادی ندارد در روبرو و دور ارتو است

ر اه حل پیشنهادی شما چیست

ساله ای با انحراف چشم و دو بینی از 33بیمار هفته قبل مراجعه کرده است 2

Ophthalmic Prism

Ali Akbar SabermoghaddamAssociated professor of OphthalmologyEye research center amp Khatam eye hospital MUMS

Prisms bend rays toward the base

PRISMS

P

cm displacement

1 m=

Prismatic Power (P)

apex

base

100 cm

X cm

Ophthalmic PrismPrismatic power

Ophthalmic Prism

bull Prisms function by bending rays of light towards the base of the prism bull The degree of bending of light depends upon the angle of incidence of light and the prismatic power

Ophthalmic prisms have been used in the treatment of binocular problems for more than 100 years

Ophthalmic Prism

Corrective Prism1 Ground ndash In Prism2 Fresnel ndash On Prism (Press-on Prisms)

Ophthalmic PrismPRESCRIBING INDUCED PRISM BY INTENTIONALLY

DISPLACING THE OPTICAL CENTERS Light traveling through the optical center of a lens encounters

no prismatic power and passes through undeviated However as the distance from the optical center increases

increasing prismatic power is encountered Prentices rule This is defined algebraically using the formula Δ = hD where Δ = prism diopters h = distance from the

optical center in centimeters and D= power of the lens in diopters

Of note the direction of displacement of light depends on whether the lens is of minus or plus power

- Minus lenses function as prisms held apex to apex that is as if the apex

of the prism were at the optical center of the lens - In other words a ray of light traveling above the optical

center encounters base-up prism power and a ray traveling below

the optical center encounters base-down prism

In the mid 1960s the 150-year-old Fresnel principle was applied to ophthalmic prisms for the first time The first ophthalmic Fresnel prism known as the wafer prism was molded of an acrylic resin making it much lighter and thinner than the corresponding powers of conventional prisms thus extending the useful range of prism powers

In 1970 the Press-OnTM prism a Fresnel-principle prism molded in flexible plastic was introduced to ophthalmologists This thin light membrane prism had the advantage of conforming and adhering to a smooth surface and thus could be affixed directly to a plano or basecurved correcting spectacle lens

Ophthalmic Prism

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Search for hurt behind nose or pinch the nose or uncomfortable frame

Atropinization of both eyes for 3 to 4 days in case with unable to relax accomodation

Explain indication in the presence of normal vision(refractive accomodative ET)

Consider full corection from infancy through pre school age

spectacle

Consider prescibe BCVA in old children

Hypermetropic correction greater than +2 in esotropic patient

spectacle

case1

5 years old girl referred to clinic for strabismusVision BCVA OD2020OS2030RefractionOD+1 sphos+2 sphEOM10ET with glass(far)30ET with glass(near)Fundus normal

What is your plan

Glass BifocalValuable in high ACA ratio accomodative ETRestricted in whom that were orthotropic or

small angle ET in far by FCR but residual ET at near that convert to orthotropia or esophoria by additional plus lens

Contraindication is amblyopia and not complete elimination of ET in near

Start with +1 sph and increase power in step of +05 up to +3 sph

Minimal power that convert ET to E prescribed(prevent excessive relaxation of accommodation)

Success depend on proper bifocal segmentPrefer straight top segment which bisect pupil

or touch lower border in straight head position

Glass Bifocal

Progressive as a substitute Fusional amplitude increase so reduce power

stepwise until discontinueIf still depend to maintain fusion during teenage

year consider surgeryFCR must be done semiannually and correction

readjustedGoal is maximal hyperopic correction but

reduce bifocal power by same amount if additional plus is necessary

Glass Bifocal

High ACA Ratio

Any uncorrected hyperopic refractive error will trigger convergenece therefore 050 D should be full corrected

It may be possible to avoid bifocal by simply slightly overplussing the patient with a single vision correction ( +050 +075D )

Bifocal strength +2 +35 D Bifocal are often eliminated in the teenage

years

6years old boy referred to strabismus clinic due to deviationparents notice occasional outward deviation of eyes especially after awakening

Vision1010 (ou) Refraction-100 (ou) EOM15 prism diopter X(near)25 prism diopter XT(far) Fundusnormal What is your plan

case2

Refractive Errors

bull Unequal clarity in vision represents an obstacle to fusion and can facilitate suppression contributing to progressive loss of control in X(T)

bull Significant RE especially astigmatism and anisometropia need to be corrected

bull All patients in minus lenses should be seen within 3 to 4 weeks after starting the therapy

bull Minus lenses should be discontinued if esotropia develops

bull There are studies that suggest that this treatment may induce myopia

bull As the child grows older asthenopic symptoms with over-minus lenses become prominent as the amount of near work increases

bull Part time patching of the non-deviating eye for four to six hours daily may convert an intermittent exotropia to a phoria

bull Although the benefit is usually temporary occlusion can be used to postpone surgical intervention in responsive patients

bull Alternate occlusion may be used in patients with equal fixation preferences

bull Initially the results are evaluated after 4 months of occlusionbull If the angle of deviation is decreased the occlusion should be

continued and assessment made every 4 months until no further change occurs

bull In case there is no improvement for 4 months it is discontinued

Occlusion

Various Non-Surgical Therapies for Intermittent Exotropia

Indications for Surgery

The AAO PPP pediatric glass prescribing guideline

bull When hyperopia and esotropia coexist initial management includes full correction of the cycloplegic refractive error

bull Later reductions in the amount of correction may be appropriate based on the amount of esotropia and level of stereopsis at near and at distance with the full cycloplegic correction in place

Hyperopia associated with partly

of full accommodative esotropia

When hyperopia is associated with overt esotropia or ever large esophoria a full cycloplegic correction should be prescribed

The principle is to prescribed the maximum plus the patient will accept without degrading the visual acuity

Generally this equals the full cyclopentolate or atropine refration upto the age 2 years because the patients enviroment is close at hand and subjective tests are not possible

In older children 050 ndash 100 D should be subtracted In some cases of acc ET an extra + 050 D could

make some difference to the strabismus

Undercorrection amp Undercorrection amp overcorrectionovercorrection

Undercorrect myopia in accommodative ET rarely tolerated

Slight overcorrection of myopia in IXTOptical overcorrection or under

correction in treatment of amblyopia(penalization)

تاری ساله اي با شكايت 60خانم دید و دو بینی در نگاه نزدیک علیرغم

استفاده از عینک نزدیک مراجعه کرده است قدرت و ساخت عینک نزدیک

ایرادی ندارد در روبرو و دور ارتو است

ر اه حل پیشنهادی شما چیست

ساله ای با انحراف چشم و دو بینی از 33بیمار هفته قبل مراجعه کرده است 2

Ophthalmic Prism

Ali Akbar SabermoghaddamAssociated professor of OphthalmologyEye research center amp Khatam eye hospital MUMS

Prisms bend rays toward the base

PRISMS

P

cm displacement

1 m=

Prismatic Power (P)

apex

base

100 cm

X cm

Ophthalmic PrismPrismatic power

Ophthalmic Prism

bull Prisms function by bending rays of light towards the base of the prism bull The degree of bending of light depends upon the angle of incidence of light and the prismatic power

Ophthalmic prisms have been used in the treatment of binocular problems for more than 100 years

Ophthalmic Prism

Corrective Prism1 Ground ndash In Prism2 Fresnel ndash On Prism (Press-on Prisms)

Ophthalmic PrismPRESCRIBING INDUCED PRISM BY INTENTIONALLY

DISPLACING THE OPTICAL CENTERS Light traveling through the optical center of a lens encounters

no prismatic power and passes through undeviated However as the distance from the optical center increases

increasing prismatic power is encountered Prentices rule This is defined algebraically using the formula Δ = hD where Δ = prism diopters h = distance from the

optical center in centimeters and D= power of the lens in diopters

Of note the direction of displacement of light depends on whether the lens is of minus or plus power

- Minus lenses function as prisms held apex to apex that is as if the apex

of the prism were at the optical center of the lens - In other words a ray of light traveling above the optical

center encounters base-up prism power and a ray traveling below

the optical center encounters base-down prism

In the mid 1960s the 150-year-old Fresnel principle was applied to ophthalmic prisms for the first time The first ophthalmic Fresnel prism known as the wafer prism was molded of an acrylic resin making it much lighter and thinner than the corresponding powers of conventional prisms thus extending the useful range of prism powers

In 1970 the Press-OnTM prism a Fresnel-principle prism molded in flexible plastic was introduced to ophthalmologists This thin light membrane prism had the advantage of conforming and adhering to a smooth surface and thus could be affixed directly to a plano or basecurved correcting spectacle lens

Ophthalmic Prism

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Consider prescibe BCVA in old children

Hypermetropic correction greater than +2 in esotropic patient

spectacle

case1

5 years old girl referred to clinic for strabismusVision BCVA OD2020OS2030RefractionOD+1 sphos+2 sphEOM10ET with glass(far)30ET with glass(near)Fundus normal

What is your plan

Glass BifocalValuable in high ACA ratio accomodative ETRestricted in whom that were orthotropic or

small angle ET in far by FCR but residual ET at near that convert to orthotropia or esophoria by additional plus lens

Contraindication is amblyopia and not complete elimination of ET in near

Start with +1 sph and increase power in step of +05 up to +3 sph

Minimal power that convert ET to E prescribed(prevent excessive relaxation of accommodation)

Success depend on proper bifocal segmentPrefer straight top segment which bisect pupil

or touch lower border in straight head position

Glass Bifocal

Progressive as a substitute Fusional amplitude increase so reduce power

stepwise until discontinueIf still depend to maintain fusion during teenage

year consider surgeryFCR must be done semiannually and correction

readjustedGoal is maximal hyperopic correction but

reduce bifocal power by same amount if additional plus is necessary

Glass Bifocal

High ACA Ratio

Any uncorrected hyperopic refractive error will trigger convergenece therefore 050 D should be full corrected

It may be possible to avoid bifocal by simply slightly overplussing the patient with a single vision correction ( +050 +075D )

Bifocal strength +2 +35 D Bifocal are often eliminated in the teenage

years

6years old boy referred to strabismus clinic due to deviationparents notice occasional outward deviation of eyes especially after awakening

Vision1010 (ou) Refraction-100 (ou) EOM15 prism diopter X(near)25 prism diopter XT(far) Fundusnormal What is your plan

case2

Refractive Errors

bull Unequal clarity in vision represents an obstacle to fusion and can facilitate suppression contributing to progressive loss of control in X(T)

bull Significant RE especially astigmatism and anisometropia need to be corrected

bull All patients in minus lenses should be seen within 3 to 4 weeks after starting the therapy

bull Minus lenses should be discontinued if esotropia develops

bull There are studies that suggest that this treatment may induce myopia

bull As the child grows older asthenopic symptoms with over-minus lenses become prominent as the amount of near work increases

bull Part time patching of the non-deviating eye for four to six hours daily may convert an intermittent exotropia to a phoria

bull Although the benefit is usually temporary occlusion can be used to postpone surgical intervention in responsive patients

bull Alternate occlusion may be used in patients with equal fixation preferences

bull Initially the results are evaluated after 4 months of occlusionbull If the angle of deviation is decreased the occlusion should be

continued and assessment made every 4 months until no further change occurs

bull In case there is no improvement for 4 months it is discontinued

Occlusion

Various Non-Surgical Therapies for Intermittent Exotropia

Indications for Surgery

The AAO PPP pediatric glass prescribing guideline

bull When hyperopia and esotropia coexist initial management includes full correction of the cycloplegic refractive error

bull Later reductions in the amount of correction may be appropriate based on the amount of esotropia and level of stereopsis at near and at distance with the full cycloplegic correction in place

Hyperopia associated with partly

of full accommodative esotropia

When hyperopia is associated with overt esotropia or ever large esophoria a full cycloplegic correction should be prescribed

The principle is to prescribed the maximum plus the patient will accept without degrading the visual acuity

Generally this equals the full cyclopentolate or atropine refration upto the age 2 years because the patients enviroment is close at hand and subjective tests are not possible

In older children 050 ndash 100 D should be subtracted In some cases of acc ET an extra + 050 D could

make some difference to the strabismus

Undercorrection amp Undercorrection amp overcorrectionovercorrection

Undercorrect myopia in accommodative ET rarely tolerated

Slight overcorrection of myopia in IXTOptical overcorrection or under

correction in treatment of amblyopia(penalization)

تاری ساله اي با شكايت 60خانم دید و دو بینی در نگاه نزدیک علیرغم

استفاده از عینک نزدیک مراجعه کرده است قدرت و ساخت عینک نزدیک

ایرادی ندارد در روبرو و دور ارتو است

ر اه حل پیشنهادی شما چیست

ساله ای با انحراف چشم و دو بینی از 33بیمار هفته قبل مراجعه کرده است 2

Ophthalmic Prism

Ali Akbar SabermoghaddamAssociated professor of OphthalmologyEye research center amp Khatam eye hospital MUMS

Prisms bend rays toward the base

PRISMS

P

cm displacement

1 m=

Prismatic Power (P)

apex

base

100 cm

X cm

Ophthalmic PrismPrismatic power

Ophthalmic Prism

bull Prisms function by bending rays of light towards the base of the prism bull The degree of bending of light depends upon the angle of incidence of light and the prismatic power

Ophthalmic prisms have been used in the treatment of binocular problems for more than 100 years

Ophthalmic Prism

Corrective Prism1 Ground ndash In Prism2 Fresnel ndash On Prism (Press-on Prisms)

Ophthalmic PrismPRESCRIBING INDUCED PRISM BY INTENTIONALLY

DISPLACING THE OPTICAL CENTERS Light traveling through the optical center of a lens encounters

no prismatic power and passes through undeviated However as the distance from the optical center increases

increasing prismatic power is encountered Prentices rule This is defined algebraically using the formula Δ = hD where Δ = prism diopters h = distance from the

optical center in centimeters and D= power of the lens in diopters

Of note the direction of displacement of light depends on whether the lens is of minus or plus power

- Minus lenses function as prisms held apex to apex that is as if the apex

of the prism were at the optical center of the lens - In other words a ray of light traveling above the optical

center encounters base-up prism power and a ray traveling below

the optical center encounters base-down prism

In the mid 1960s the 150-year-old Fresnel principle was applied to ophthalmic prisms for the first time The first ophthalmic Fresnel prism known as the wafer prism was molded of an acrylic resin making it much lighter and thinner than the corresponding powers of conventional prisms thus extending the useful range of prism powers

In 1970 the Press-OnTM prism a Fresnel-principle prism molded in flexible plastic was introduced to ophthalmologists This thin light membrane prism had the advantage of conforming and adhering to a smooth surface and thus could be affixed directly to a plano or basecurved correcting spectacle lens

Ophthalmic Prism

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

case1

5 years old girl referred to clinic for strabismusVision BCVA OD2020OS2030RefractionOD+1 sphos+2 sphEOM10ET with glass(far)30ET with glass(near)Fundus normal

What is your plan

Glass BifocalValuable in high ACA ratio accomodative ETRestricted in whom that were orthotropic or

small angle ET in far by FCR but residual ET at near that convert to orthotropia or esophoria by additional plus lens

Contraindication is amblyopia and not complete elimination of ET in near

Start with +1 sph and increase power in step of +05 up to +3 sph

Minimal power that convert ET to E prescribed(prevent excessive relaxation of accommodation)

Success depend on proper bifocal segmentPrefer straight top segment which bisect pupil

or touch lower border in straight head position

Glass Bifocal

Progressive as a substitute Fusional amplitude increase so reduce power

stepwise until discontinueIf still depend to maintain fusion during teenage

year consider surgeryFCR must be done semiannually and correction

readjustedGoal is maximal hyperopic correction but

reduce bifocal power by same amount if additional plus is necessary

Glass Bifocal

High ACA Ratio

Any uncorrected hyperopic refractive error will trigger convergenece therefore 050 D should be full corrected

It may be possible to avoid bifocal by simply slightly overplussing the patient with a single vision correction ( +050 +075D )

Bifocal strength +2 +35 D Bifocal are often eliminated in the teenage

years

6years old boy referred to strabismus clinic due to deviationparents notice occasional outward deviation of eyes especially after awakening

Vision1010 (ou) Refraction-100 (ou) EOM15 prism diopter X(near)25 prism diopter XT(far) Fundusnormal What is your plan

case2

Refractive Errors

bull Unequal clarity in vision represents an obstacle to fusion and can facilitate suppression contributing to progressive loss of control in X(T)

bull Significant RE especially astigmatism and anisometropia need to be corrected

bull All patients in minus lenses should be seen within 3 to 4 weeks after starting the therapy

bull Minus lenses should be discontinued if esotropia develops

bull There are studies that suggest that this treatment may induce myopia

bull As the child grows older asthenopic symptoms with over-minus lenses become prominent as the amount of near work increases

bull Part time patching of the non-deviating eye for four to six hours daily may convert an intermittent exotropia to a phoria

bull Although the benefit is usually temporary occlusion can be used to postpone surgical intervention in responsive patients

bull Alternate occlusion may be used in patients with equal fixation preferences

bull Initially the results are evaluated after 4 months of occlusionbull If the angle of deviation is decreased the occlusion should be

continued and assessment made every 4 months until no further change occurs

bull In case there is no improvement for 4 months it is discontinued

Occlusion

Various Non-Surgical Therapies for Intermittent Exotropia

Indications for Surgery

The AAO PPP pediatric glass prescribing guideline

bull When hyperopia and esotropia coexist initial management includes full correction of the cycloplegic refractive error

bull Later reductions in the amount of correction may be appropriate based on the amount of esotropia and level of stereopsis at near and at distance with the full cycloplegic correction in place

Hyperopia associated with partly

of full accommodative esotropia

When hyperopia is associated with overt esotropia or ever large esophoria a full cycloplegic correction should be prescribed

The principle is to prescribed the maximum plus the patient will accept without degrading the visual acuity

Generally this equals the full cyclopentolate or atropine refration upto the age 2 years because the patients enviroment is close at hand and subjective tests are not possible

In older children 050 ndash 100 D should be subtracted In some cases of acc ET an extra + 050 D could

make some difference to the strabismus

Undercorrection amp Undercorrection amp overcorrectionovercorrection

Undercorrect myopia in accommodative ET rarely tolerated

Slight overcorrection of myopia in IXTOptical overcorrection or under

correction in treatment of amblyopia(penalization)

تاری ساله اي با شكايت 60خانم دید و دو بینی در نگاه نزدیک علیرغم

استفاده از عینک نزدیک مراجعه کرده است قدرت و ساخت عینک نزدیک

ایرادی ندارد در روبرو و دور ارتو است

ر اه حل پیشنهادی شما چیست

ساله ای با انحراف چشم و دو بینی از 33بیمار هفته قبل مراجعه کرده است 2

Ophthalmic Prism

Ali Akbar SabermoghaddamAssociated professor of OphthalmologyEye research center amp Khatam eye hospital MUMS

Prisms bend rays toward the base

PRISMS

P

cm displacement

1 m=

Prismatic Power (P)

apex

base

100 cm

X cm

Ophthalmic PrismPrismatic power

Ophthalmic Prism

bull Prisms function by bending rays of light towards the base of the prism bull The degree of bending of light depends upon the angle of incidence of light and the prismatic power

Ophthalmic prisms have been used in the treatment of binocular problems for more than 100 years

Ophthalmic Prism

Corrective Prism1 Ground ndash In Prism2 Fresnel ndash On Prism (Press-on Prisms)

Ophthalmic PrismPRESCRIBING INDUCED PRISM BY INTENTIONALLY

DISPLACING THE OPTICAL CENTERS Light traveling through the optical center of a lens encounters

no prismatic power and passes through undeviated However as the distance from the optical center increases

increasing prismatic power is encountered Prentices rule This is defined algebraically using the formula Δ = hD where Δ = prism diopters h = distance from the

optical center in centimeters and D= power of the lens in diopters

Of note the direction of displacement of light depends on whether the lens is of minus or plus power

- Minus lenses function as prisms held apex to apex that is as if the apex

of the prism were at the optical center of the lens - In other words a ray of light traveling above the optical

center encounters base-up prism power and a ray traveling below

the optical center encounters base-down prism

In the mid 1960s the 150-year-old Fresnel principle was applied to ophthalmic prisms for the first time The first ophthalmic Fresnel prism known as the wafer prism was molded of an acrylic resin making it much lighter and thinner than the corresponding powers of conventional prisms thus extending the useful range of prism powers

In 1970 the Press-OnTM prism a Fresnel-principle prism molded in flexible plastic was introduced to ophthalmologists This thin light membrane prism had the advantage of conforming and adhering to a smooth surface and thus could be affixed directly to a plano or basecurved correcting spectacle lens

Ophthalmic Prism

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Glass BifocalValuable in high ACA ratio accomodative ETRestricted in whom that were orthotropic or

small angle ET in far by FCR but residual ET at near that convert to orthotropia or esophoria by additional plus lens

Contraindication is amblyopia and not complete elimination of ET in near

Start with +1 sph and increase power in step of +05 up to +3 sph

Minimal power that convert ET to E prescribed(prevent excessive relaxation of accommodation)

Success depend on proper bifocal segmentPrefer straight top segment which bisect pupil

or touch lower border in straight head position

Glass Bifocal

Progressive as a substitute Fusional amplitude increase so reduce power

stepwise until discontinueIf still depend to maintain fusion during teenage

year consider surgeryFCR must be done semiannually and correction

readjustedGoal is maximal hyperopic correction but

reduce bifocal power by same amount if additional plus is necessary

Glass Bifocal

High ACA Ratio

Any uncorrected hyperopic refractive error will trigger convergenece therefore 050 D should be full corrected

It may be possible to avoid bifocal by simply slightly overplussing the patient with a single vision correction ( +050 +075D )

Bifocal strength +2 +35 D Bifocal are often eliminated in the teenage

years

6years old boy referred to strabismus clinic due to deviationparents notice occasional outward deviation of eyes especially after awakening

Vision1010 (ou) Refraction-100 (ou) EOM15 prism diopter X(near)25 prism diopter XT(far) Fundusnormal What is your plan

case2

Refractive Errors

bull Unequal clarity in vision represents an obstacle to fusion and can facilitate suppression contributing to progressive loss of control in X(T)

bull Significant RE especially astigmatism and anisometropia need to be corrected

bull All patients in minus lenses should be seen within 3 to 4 weeks after starting the therapy

bull Minus lenses should be discontinued if esotropia develops

bull There are studies that suggest that this treatment may induce myopia

bull As the child grows older asthenopic symptoms with over-minus lenses become prominent as the amount of near work increases

bull Part time patching of the non-deviating eye for four to six hours daily may convert an intermittent exotropia to a phoria

bull Although the benefit is usually temporary occlusion can be used to postpone surgical intervention in responsive patients

bull Alternate occlusion may be used in patients with equal fixation preferences

bull Initially the results are evaluated after 4 months of occlusionbull If the angle of deviation is decreased the occlusion should be

continued and assessment made every 4 months until no further change occurs

bull In case there is no improvement for 4 months it is discontinued

Occlusion

Various Non-Surgical Therapies for Intermittent Exotropia

Indications for Surgery

The AAO PPP pediatric glass prescribing guideline

bull When hyperopia and esotropia coexist initial management includes full correction of the cycloplegic refractive error

bull Later reductions in the amount of correction may be appropriate based on the amount of esotropia and level of stereopsis at near and at distance with the full cycloplegic correction in place

Hyperopia associated with partly

of full accommodative esotropia

When hyperopia is associated with overt esotropia or ever large esophoria a full cycloplegic correction should be prescribed

The principle is to prescribed the maximum plus the patient will accept without degrading the visual acuity

Generally this equals the full cyclopentolate or atropine refration upto the age 2 years because the patients enviroment is close at hand and subjective tests are not possible

In older children 050 ndash 100 D should be subtracted In some cases of acc ET an extra + 050 D could

make some difference to the strabismus

Undercorrection amp Undercorrection amp overcorrectionovercorrection

Undercorrect myopia in accommodative ET rarely tolerated

Slight overcorrection of myopia in IXTOptical overcorrection or under

correction in treatment of amblyopia(penalization)

تاری ساله اي با شكايت 60خانم دید و دو بینی در نگاه نزدیک علیرغم

استفاده از عینک نزدیک مراجعه کرده است قدرت و ساخت عینک نزدیک

ایرادی ندارد در روبرو و دور ارتو است

ر اه حل پیشنهادی شما چیست

ساله ای با انحراف چشم و دو بینی از 33بیمار هفته قبل مراجعه کرده است 2

Ophthalmic Prism

Ali Akbar SabermoghaddamAssociated professor of OphthalmologyEye research center amp Khatam eye hospital MUMS

Prisms bend rays toward the base

PRISMS

P

cm displacement

1 m=

Prismatic Power (P)

apex

base

100 cm

X cm

Ophthalmic PrismPrismatic power

Ophthalmic Prism

bull Prisms function by bending rays of light towards the base of the prism bull The degree of bending of light depends upon the angle of incidence of light and the prismatic power

Ophthalmic prisms have been used in the treatment of binocular problems for more than 100 years

Ophthalmic Prism

Corrective Prism1 Ground ndash In Prism2 Fresnel ndash On Prism (Press-on Prisms)

Ophthalmic PrismPRESCRIBING INDUCED PRISM BY INTENTIONALLY

DISPLACING THE OPTICAL CENTERS Light traveling through the optical center of a lens encounters

no prismatic power and passes through undeviated However as the distance from the optical center increases

increasing prismatic power is encountered Prentices rule This is defined algebraically using the formula Δ = hD where Δ = prism diopters h = distance from the

optical center in centimeters and D= power of the lens in diopters

Of note the direction of displacement of light depends on whether the lens is of minus or plus power

- Minus lenses function as prisms held apex to apex that is as if the apex

of the prism were at the optical center of the lens - In other words a ray of light traveling above the optical

center encounters base-up prism power and a ray traveling below

the optical center encounters base-down prism

In the mid 1960s the 150-year-old Fresnel principle was applied to ophthalmic prisms for the first time The first ophthalmic Fresnel prism known as the wafer prism was molded of an acrylic resin making it much lighter and thinner than the corresponding powers of conventional prisms thus extending the useful range of prism powers

In 1970 the Press-OnTM prism a Fresnel-principle prism molded in flexible plastic was introduced to ophthalmologists This thin light membrane prism had the advantage of conforming and adhering to a smooth surface and thus could be affixed directly to a plano or basecurved correcting spectacle lens

Ophthalmic Prism

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Start with +1 sph and increase power in step of +05 up to +3 sph

Minimal power that convert ET to E prescribed(prevent excessive relaxation of accommodation)

Success depend on proper bifocal segmentPrefer straight top segment which bisect pupil

or touch lower border in straight head position

Glass Bifocal

Progressive as a substitute Fusional amplitude increase so reduce power

stepwise until discontinueIf still depend to maintain fusion during teenage

year consider surgeryFCR must be done semiannually and correction

readjustedGoal is maximal hyperopic correction but

reduce bifocal power by same amount if additional plus is necessary

Glass Bifocal

High ACA Ratio

Any uncorrected hyperopic refractive error will trigger convergenece therefore 050 D should be full corrected

It may be possible to avoid bifocal by simply slightly overplussing the patient with a single vision correction ( +050 +075D )

Bifocal strength +2 +35 D Bifocal are often eliminated in the teenage

years

6years old boy referred to strabismus clinic due to deviationparents notice occasional outward deviation of eyes especially after awakening

Vision1010 (ou) Refraction-100 (ou) EOM15 prism diopter X(near)25 prism diopter XT(far) Fundusnormal What is your plan

case2

Refractive Errors

bull Unequal clarity in vision represents an obstacle to fusion and can facilitate suppression contributing to progressive loss of control in X(T)

bull Significant RE especially astigmatism and anisometropia need to be corrected

bull All patients in minus lenses should be seen within 3 to 4 weeks after starting the therapy

bull Minus lenses should be discontinued if esotropia develops

bull There are studies that suggest that this treatment may induce myopia

bull As the child grows older asthenopic symptoms with over-minus lenses become prominent as the amount of near work increases

bull Part time patching of the non-deviating eye for four to six hours daily may convert an intermittent exotropia to a phoria

bull Although the benefit is usually temporary occlusion can be used to postpone surgical intervention in responsive patients

bull Alternate occlusion may be used in patients with equal fixation preferences

bull Initially the results are evaluated after 4 months of occlusionbull If the angle of deviation is decreased the occlusion should be

continued and assessment made every 4 months until no further change occurs

bull In case there is no improvement for 4 months it is discontinued

Occlusion

Various Non-Surgical Therapies for Intermittent Exotropia

Indications for Surgery

The AAO PPP pediatric glass prescribing guideline

bull When hyperopia and esotropia coexist initial management includes full correction of the cycloplegic refractive error

bull Later reductions in the amount of correction may be appropriate based on the amount of esotropia and level of stereopsis at near and at distance with the full cycloplegic correction in place

Hyperopia associated with partly

of full accommodative esotropia

When hyperopia is associated with overt esotropia or ever large esophoria a full cycloplegic correction should be prescribed

The principle is to prescribed the maximum plus the patient will accept without degrading the visual acuity

Generally this equals the full cyclopentolate or atropine refration upto the age 2 years because the patients enviroment is close at hand and subjective tests are not possible

In older children 050 ndash 100 D should be subtracted In some cases of acc ET an extra + 050 D could

make some difference to the strabismus

Undercorrection amp Undercorrection amp overcorrectionovercorrection

Undercorrect myopia in accommodative ET rarely tolerated

Slight overcorrection of myopia in IXTOptical overcorrection or under

correction in treatment of amblyopia(penalization)

تاری ساله اي با شكايت 60خانم دید و دو بینی در نگاه نزدیک علیرغم

استفاده از عینک نزدیک مراجعه کرده است قدرت و ساخت عینک نزدیک

ایرادی ندارد در روبرو و دور ارتو است

ر اه حل پیشنهادی شما چیست

ساله ای با انحراف چشم و دو بینی از 33بیمار هفته قبل مراجعه کرده است 2

Ophthalmic Prism

Ali Akbar SabermoghaddamAssociated professor of OphthalmologyEye research center amp Khatam eye hospital MUMS

Prisms bend rays toward the base

PRISMS

P

cm displacement

1 m=

Prismatic Power (P)

apex

base

100 cm

X cm

Ophthalmic PrismPrismatic power

Ophthalmic Prism

bull Prisms function by bending rays of light towards the base of the prism bull The degree of bending of light depends upon the angle of incidence of light and the prismatic power

Ophthalmic prisms have been used in the treatment of binocular problems for more than 100 years

Ophthalmic Prism

Corrective Prism1 Ground ndash In Prism2 Fresnel ndash On Prism (Press-on Prisms)

Ophthalmic PrismPRESCRIBING INDUCED PRISM BY INTENTIONALLY

DISPLACING THE OPTICAL CENTERS Light traveling through the optical center of a lens encounters

no prismatic power and passes through undeviated However as the distance from the optical center increases

increasing prismatic power is encountered Prentices rule This is defined algebraically using the formula Δ = hD where Δ = prism diopters h = distance from the

optical center in centimeters and D= power of the lens in diopters

Of note the direction of displacement of light depends on whether the lens is of minus or plus power

- Minus lenses function as prisms held apex to apex that is as if the apex

of the prism were at the optical center of the lens - In other words a ray of light traveling above the optical

center encounters base-up prism power and a ray traveling below

the optical center encounters base-down prism

In the mid 1960s the 150-year-old Fresnel principle was applied to ophthalmic prisms for the first time The first ophthalmic Fresnel prism known as the wafer prism was molded of an acrylic resin making it much lighter and thinner than the corresponding powers of conventional prisms thus extending the useful range of prism powers

In 1970 the Press-OnTM prism a Fresnel-principle prism molded in flexible plastic was introduced to ophthalmologists This thin light membrane prism had the advantage of conforming and adhering to a smooth surface and thus could be affixed directly to a plano or basecurved correcting spectacle lens

Ophthalmic Prism

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Progressive as a substitute Fusional amplitude increase so reduce power

stepwise until discontinueIf still depend to maintain fusion during teenage

year consider surgeryFCR must be done semiannually and correction

readjustedGoal is maximal hyperopic correction but

reduce bifocal power by same amount if additional plus is necessary

Glass Bifocal

High ACA Ratio

Any uncorrected hyperopic refractive error will trigger convergenece therefore 050 D should be full corrected

It may be possible to avoid bifocal by simply slightly overplussing the patient with a single vision correction ( +050 +075D )

Bifocal strength +2 +35 D Bifocal are often eliminated in the teenage

years

6years old boy referred to strabismus clinic due to deviationparents notice occasional outward deviation of eyes especially after awakening

Vision1010 (ou) Refraction-100 (ou) EOM15 prism diopter X(near)25 prism diopter XT(far) Fundusnormal What is your plan

case2

Refractive Errors

bull Unequal clarity in vision represents an obstacle to fusion and can facilitate suppression contributing to progressive loss of control in X(T)

bull Significant RE especially astigmatism and anisometropia need to be corrected

bull All patients in minus lenses should be seen within 3 to 4 weeks after starting the therapy

bull Minus lenses should be discontinued if esotropia develops

bull There are studies that suggest that this treatment may induce myopia

bull As the child grows older asthenopic symptoms with over-minus lenses become prominent as the amount of near work increases

bull Part time patching of the non-deviating eye for four to six hours daily may convert an intermittent exotropia to a phoria

bull Although the benefit is usually temporary occlusion can be used to postpone surgical intervention in responsive patients

bull Alternate occlusion may be used in patients with equal fixation preferences

bull Initially the results are evaluated after 4 months of occlusionbull If the angle of deviation is decreased the occlusion should be

continued and assessment made every 4 months until no further change occurs

bull In case there is no improvement for 4 months it is discontinued

Occlusion

Various Non-Surgical Therapies for Intermittent Exotropia

Indications for Surgery

The AAO PPP pediatric glass prescribing guideline

bull When hyperopia and esotropia coexist initial management includes full correction of the cycloplegic refractive error

bull Later reductions in the amount of correction may be appropriate based on the amount of esotropia and level of stereopsis at near and at distance with the full cycloplegic correction in place

Hyperopia associated with partly

of full accommodative esotropia

When hyperopia is associated with overt esotropia or ever large esophoria a full cycloplegic correction should be prescribed

The principle is to prescribed the maximum plus the patient will accept without degrading the visual acuity

Generally this equals the full cyclopentolate or atropine refration upto the age 2 years because the patients enviroment is close at hand and subjective tests are not possible

In older children 050 ndash 100 D should be subtracted In some cases of acc ET an extra + 050 D could

make some difference to the strabismus

Undercorrection amp Undercorrection amp overcorrectionovercorrection

Undercorrect myopia in accommodative ET rarely tolerated

Slight overcorrection of myopia in IXTOptical overcorrection or under

correction in treatment of amblyopia(penalization)

تاری ساله اي با شكايت 60خانم دید و دو بینی در نگاه نزدیک علیرغم

استفاده از عینک نزدیک مراجعه کرده است قدرت و ساخت عینک نزدیک

ایرادی ندارد در روبرو و دور ارتو است

ر اه حل پیشنهادی شما چیست

ساله ای با انحراف چشم و دو بینی از 33بیمار هفته قبل مراجعه کرده است 2

Ophthalmic Prism

Ali Akbar SabermoghaddamAssociated professor of OphthalmologyEye research center amp Khatam eye hospital MUMS

Prisms bend rays toward the base

PRISMS

P

cm displacement

1 m=

Prismatic Power (P)

apex

base

100 cm

X cm

Ophthalmic PrismPrismatic power

Ophthalmic Prism

bull Prisms function by bending rays of light towards the base of the prism bull The degree of bending of light depends upon the angle of incidence of light and the prismatic power

Ophthalmic prisms have been used in the treatment of binocular problems for more than 100 years

Ophthalmic Prism

Corrective Prism1 Ground ndash In Prism2 Fresnel ndash On Prism (Press-on Prisms)

Ophthalmic PrismPRESCRIBING INDUCED PRISM BY INTENTIONALLY

DISPLACING THE OPTICAL CENTERS Light traveling through the optical center of a lens encounters

no prismatic power and passes through undeviated However as the distance from the optical center increases

increasing prismatic power is encountered Prentices rule This is defined algebraically using the formula Δ = hD where Δ = prism diopters h = distance from the

optical center in centimeters and D= power of the lens in diopters

Of note the direction of displacement of light depends on whether the lens is of minus or plus power

- Minus lenses function as prisms held apex to apex that is as if the apex

of the prism were at the optical center of the lens - In other words a ray of light traveling above the optical

center encounters base-up prism power and a ray traveling below

the optical center encounters base-down prism

In the mid 1960s the 150-year-old Fresnel principle was applied to ophthalmic prisms for the first time The first ophthalmic Fresnel prism known as the wafer prism was molded of an acrylic resin making it much lighter and thinner than the corresponding powers of conventional prisms thus extending the useful range of prism powers

In 1970 the Press-OnTM prism a Fresnel-principle prism molded in flexible plastic was introduced to ophthalmologists This thin light membrane prism had the advantage of conforming and adhering to a smooth surface and thus could be affixed directly to a plano or basecurved correcting spectacle lens

Ophthalmic Prism

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

High ACA Ratio

Any uncorrected hyperopic refractive error will trigger convergenece therefore 050 D should be full corrected

It may be possible to avoid bifocal by simply slightly overplussing the patient with a single vision correction ( +050 +075D )

Bifocal strength +2 +35 D Bifocal are often eliminated in the teenage

years

6years old boy referred to strabismus clinic due to deviationparents notice occasional outward deviation of eyes especially after awakening

Vision1010 (ou) Refraction-100 (ou) EOM15 prism diopter X(near)25 prism diopter XT(far) Fundusnormal What is your plan

case2

Refractive Errors

bull Unequal clarity in vision represents an obstacle to fusion and can facilitate suppression contributing to progressive loss of control in X(T)

bull Significant RE especially astigmatism and anisometropia need to be corrected

bull All patients in minus lenses should be seen within 3 to 4 weeks after starting the therapy

bull Minus lenses should be discontinued if esotropia develops

bull There are studies that suggest that this treatment may induce myopia

bull As the child grows older asthenopic symptoms with over-minus lenses become prominent as the amount of near work increases

bull Part time patching of the non-deviating eye for four to six hours daily may convert an intermittent exotropia to a phoria

bull Although the benefit is usually temporary occlusion can be used to postpone surgical intervention in responsive patients

bull Alternate occlusion may be used in patients with equal fixation preferences

bull Initially the results are evaluated after 4 months of occlusionbull If the angle of deviation is decreased the occlusion should be

continued and assessment made every 4 months until no further change occurs

bull In case there is no improvement for 4 months it is discontinued

Occlusion

Various Non-Surgical Therapies for Intermittent Exotropia

Indications for Surgery

The AAO PPP pediatric glass prescribing guideline

bull When hyperopia and esotropia coexist initial management includes full correction of the cycloplegic refractive error

bull Later reductions in the amount of correction may be appropriate based on the amount of esotropia and level of stereopsis at near and at distance with the full cycloplegic correction in place

Hyperopia associated with partly

of full accommodative esotropia

When hyperopia is associated with overt esotropia or ever large esophoria a full cycloplegic correction should be prescribed

The principle is to prescribed the maximum plus the patient will accept without degrading the visual acuity

Generally this equals the full cyclopentolate or atropine refration upto the age 2 years because the patients enviroment is close at hand and subjective tests are not possible

In older children 050 ndash 100 D should be subtracted In some cases of acc ET an extra + 050 D could

make some difference to the strabismus

Undercorrection amp Undercorrection amp overcorrectionovercorrection

Undercorrect myopia in accommodative ET rarely tolerated

Slight overcorrection of myopia in IXTOptical overcorrection or under

correction in treatment of amblyopia(penalization)

تاری ساله اي با شكايت 60خانم دید و دو بینی در نگاه نزدیک علیرغم

استفاده از عینک نزدیک مراجعه کرده است قدرت و ساخت عینک نزدیک

ایرادی ندارد در روبرو و دور ارتو است

ر اه حل پیشنهادی شما چیست

ساله ای با انحراف چشم و دو بینی از 33بیمار هفته قبل مراجعه کرده است 2

Ophthalmic Prism

Ali Akbar SabermoghaddamAssociated professor of OphthalmologyEye research center amp Khatam eye hospital MUMS

Prisms bend rays toward the base

PRISMS

P

cm displacement

1 m=

Prismatic Power (P)

apex

base

100 cm

X cm

Ophthalmic PrismPrismatic power

Ophthalmic Prism

bull Prisms function by bending rays of light towards the base of the prism bull The degree of bending of light depends upon the angle of incidence of light and the prismatic power

Ophthalmic prisms have been used in the treatment of binocular problems for more than 100 years

Ophthalmic Prism

Corrective Prism1 Ground ndash In Prism2 Fresnel ndash On Prism (Press-on Prisms)

Ophthalmic PrismPRESCRIBING INDUCED PRISM BY INTENTIONALLY

DISPLACING THE OPTICAL CENTERS Light traveling through the optical center of a lens encounters

no prismatic power and passes through undeviated However as the distance from the optical center increases

increasing prismatic power is encountered Prentices rule This is defined algebraically using the formula Δ = hD where Δ = prism diopters h = distance from the

optical center in centimeters and D= power of the lens in diopters

Of note the direction of displacement of light depends on whether the lens is of minus or plus power

- Minus lenses function as prisms held apex to apex that is as if the apex

of the prism were at the optical center of the lens - In other words a ray of light traveling above the optical

center encounters base-up prism power and a ray traveling below

the optical center encounters base-down prism

In the mid 1960s the 150-year-old Fresnel principle was applied to ophthalmic prisms for the first time The first ophthalmic Fresnel prism known as the wafer prism was molded of an acrylic resin making it much lighter and thinner than the corresponding powers of conventional prisms thus extending the useful range of prism powers

In 1970 the Press-OnTM prism a Fresnel-principle prism molded in flexible plastic was introduced to ophthalmologists This thin light membrane prism had the advantage of conforming and adhering to a smooth surface and thus could be affixed directly to a plano or basecurved correcting spectacle lens

Ophthalmic Prism

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

6years old boy referred to strabismus clinic due to deviationparents notice occasional outward deviation of eyes especially after awakening

Vision1010 (ou) Refraction-100 (ou) EOM15 prism diopter X(near)25 prism diopter XT(far) Fundusnormal What is your plan

case2

Refractive Errors

bull Unequal clarity in vision represents an obstacle to fusion and can facilitate suppression contributing to progressive loss of control in X(T)

bull Significant RE especially astigmatism and anisometropia need to be corrected

bull All patients in minus lenses should be seen within 3 to 4 weeks after starting the therapy

bull Minus lenses should be discontinued if esotropia develops

bull There are studies that suggest that this treatment may induce myopia

bull As the child grows older asthenopic symptoms with over-minus lenses become prominent as the amount of near work increases

bull Part time patching of the non-deviating eye for four to six hours daily may convert an intermittent exotropia to a phoria

bull Although the benefit is usually temporary occlusion can be used to postpone surgical intervention in responsive patients

bull Alternate occlusion may be used in patients with equal fixation preferences

bull Initially the results are evaluated after 4 months of occlusionbull If the angle of deviation is decreased the occlusion should be

continued and assessment made every 4 months until no further change occurs

bull In case there is no improvement for 4 months it is discontinued

Occlusion

Various Non-Surgical Therapies for Intermittent Exotropia

Indications for Surgery

The AAO PPP pediatric glass prescribing guideline

bull When hyperopia and esotropia coexist initial management includes full correction of the cycloplegic refractive error

bull Later reductions in the amount of correction may be appropriate based on the amount of esotropia and level of stereopsis at near and at distance with the full cycloplegic correction in place

Hyperopia associated with partly

of full accommodative esotropia

When hyperopia is associated with overt esotropia or ever large esophoria a full cycloplegic correction should be prescribed

The principle is to prescribed the maximum plus the patient will accept without degrading the visual acuity

Generally this equals the full cyclopentolate or atropine refration upto the age 2 years because the patients enviroment is close at hand and subjective tests are not possible

In older children 050 ndash 100 D should be subtracted In some cases of acc ET an extra + 050 D could

make some difference to the strabismus

Undercorrection amp Undercorrection amp overcorrectionovercorrection

Undercorrect myopia in accommodative ET rarely tolerated

Slight overcorrection of myopia in IXTOptical overcorrection or under

correction in treatment of amblyopia(penalization)

تاری ساله اي با شكايت 60خانم دید و دو بینی در نگاه نزدیک علیرغم

استفاده از عینک نزدیک مراجعه کرده است قدرت و ساخت عینک نزدیک

ایرادی ندارد در روبرو و دور ارتو است

ر اه حل پیشنهادی شما چیست

ساله ای با انحراف چشم و دو بینی از 33بیمار هفته قبل مراجعه کرده است 2

Ophthalmic Prism

Ali Akbar SabermoghaddamAssociated professor of OphthalmologyEye research center amp Khatam eye hospital MUMS

Prisms bend rays toward the base

PRISMS

P

cm displacement

1 m=

Prismatic Power (P)

apex

base

100 cm

X cm

Ophthalmic PrismPrismatic power

Ophthalmic Prism

bull Prisms function by bending rays of light towards the base of the prism bull The degree of bending of light depends upon the angle of incidence of light and the prismatic power

Ophthalmic prisms have been used in the treatment of binocular problems for more than 100 years

Ophthalmic Prism

Corrective Prism1 Ground ndash In Prism2 Fresnel ndash On Prism (Press-on Prisms)

Ophthalmic PrismPRESCRIBING INDUCED PRISM BY INTENTIONALLY

DISPLACING THE OPTICAL CENTERS Light traveling through the optical center of a lens encounters

no prismatic power and passes through undeviated However as the distance from the optical center increases

increasing prismatic power is encountered Prentices rule This is defined algebraically using the formula Δ = hD where Δ = prism diopters h = distance from the

optical center in centimeters and D= power of the lens in diopters

Of note the direction of displacement of light depends on whether the lens is of minus or plus power

- Minus lenses function as prisms held apex to apex that is as if the apex

of the prism were at the optical center of the lens - In other words a ray of light traveling above the optical

center encounters base-up prism power and a ray traveling below

the optical center encounters base-down prism

In the mid 1960s the 150-year-old Fresnel principle was applied to ophthalmic prisms for the first time The first ophthalmic Fresnel prism known as the wafer prism was molded of an acrylic resin making it much lighter and thinner than the corresponding powers of conventional prisms thus extending the useful range of prism powers

In 1970 the Press-OnTM prism a Fresnel-principle prism molded in flexible plastic was introduced to ophthalmologists This thin light membrane prism had the advantage of conforming and adhering to a smooth surface and thus could be affixed directly to a plano or basecurved correcting spectacle lens

Ophthalmic Prism

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Refractive Errors

bull Unequal clarity in vision represents an obstacle to fusion and can facilitate suppression contributing to progressive loss of control in X(T)

bull Significant RE especially astigmatism and anisometropia need to be corrected

bull All patients in minus lenses should be seen within 3 to 4 weeks after starting the therapy

bull Minus lenses should be discontinued if esotropia develops

bull There are studies that suggest that this treatment may induce myopia

bull As the child grows older asthenopic symptoms with over-minus lenses become prominent as the amount of near work increases

bull Part time patching of the non-deviating eye for four to six hours daily may convert an intermittent exotropia to a phoria

bull Although the benefit is usually temporary occlusion can be used to postpone surgical intervention in responsive patients

bull Alternate occlusion may be used in patients with equal fixation preferences

bull Initially the results are evaluated after 4 months of occlusionbull If the angle of deviation is decreased the occlusion should be

continued and assessment made every 4 months until no further change occurs

bull In case there is no improvement for 4 months it is discontinued

Occlusion

Various Non-Surgical Therapies for Intermittent Exotropia

Indications for Surgery

The AAO PPP pediatric glass prescribing guideline

bull When hyperopia and esotropia coexist initial management includes full correction of the cycloplegic refractive error

bull Later reductions in the amount of correction may be appropriate based on the amount of esotropia and level of stereopsis at near and at distance with the full cycloplegic correction in place

Hyperopia associated with partly

of full accommodative esotropia

When hyperopia is associated with overt esotropia or ever large esophoria a full cycloplegic correction should be prescribed

The principle is to prescribed the maximum plus the patient will accept without degrading the visual acuity

Generally this equals the full cyclopentolate or atropine refration upto the age 2 years because the patients enviroment is close at hand and subjective tests are not possible

In older children 050 ndash 100 D should be subtracted In some cases of acc ET an extra + 050 D could

make some difference to the strabismus

Undercorrection amp Undercorrection amp overcorrectionovercorrection

Undercorrect myopia in accommodative ET rarely tolerated

Slight overcorrection of myopia in IXTOptical overcorrection or under

correction in treatment of amblyopia(penalization)

تاری ساله اي با شكايت 60خانم دید و دو بینی در نگاه نزدیک علیرغم

استفاده از عینک نزدیک مراجعه کرده است قدرت و ساخت عینک نزدیک

ایرادی ندارد در روبرو و دور ارتو است

ر اه حل پیشنهادی شما چیست

ساله ای با انحراف چشم و دو بینی از 33بیمار هفته قبل مراجعه کرده است 2

Ophthalmic Prism

Ali Akbar SabermoghaddamAssociated professor of OphthalmologyEye research center amp Khatam eye hospital MUMS

Prisms bend rays toward the base

PRISMS

P

cm displacement

1 m=

Prismatic Power (P)

apex

base

100 cm

X cm

Ophthalmic PrismPrismatic power

Ophthalmic Prism

bull Prisms function by bending rays of light towards the base of the prism bull The degree of bending of light depends upon the angle of incidence of light and the prismatic power

Ophthalmic prisms have been used in the treatment of binocular problems for more than 100 years

Ophthalmic Prism

Corrective Prism1 Ground ndash In Prism2 Fresnel ndash On Prism (Press-on Prisms)

Ophthalmic PrismPRESCRIBING INDUCED PRISM BY INTENTIONALLY

DISPLACING THE OPTICAL CENTERS Light traveling through the optical center of a lens encounters

no prismatic power and passes through undeviated However as the distance from the optical center increases

increasing prismatic power is encountered Prentices rule This is defined algebraically using the formula Δ = hD where Δ = prism diopters h = distance from the

optical center in centimeters and D= power of the lens in diopters

Of note the direction of displacement of light depends on whether the lens is of minus or plus power

- Minus lenses function as prisms held apex to apex that is as if the apex

of the prism were at the optical center of the lens - In other words a ray of light traveling above the optical

center encounters base-up prism power and a ray traveling below

the optical center encounters base-down prism

In the mid 1960s the 150-year-old Fresnel principle was applied to ophthalmic prisms for the first time The first ophthalmic Fresnel prism known as the wafer prism was molded of an acrylic resin making it much lighter and thinner than the corresponding powers of conventional prisms thus extending the useful range of prism powers

In 1970 the Press-OnTM prism a Fresnel-principle prism molded in flexible plastic was introduced to ophthalmologists This thin light membrane prism had the advantage of conforming and adhering to a smooth surface and thus could be affixed directly to a plano or basecurved correcting spectacle lens

Ophthalmic Prism

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

bull All patients in minus lenses should be seen within 3 to 4 weeks after starting the therapy

bull Minus lenses should be discontinued if esotropia develops

bull There are studies that suggest that this treatment may induce myopia

bull As the child grows older asthenopic symptoms with over-minus lenses become prominent as the amount of near work increases

bull Part time patching of the non-deviating eye for four to six hours daily may convert an intermittent exotropia to a phoria

bull Although the benefit is usually temporary occlusion can be used to postpone surgical intervention in responsive patients

bull Alternate occlusion may be used in patients with equal fixation preferences

bull Initially the results are evaluated after 4 months of occlusionbull If the angle of deviation is decreased the occlusion should be

continued and assessment made every 4 months until no further change occurs

bull In case there is no improvement for 4 months it is discontinued

Occlusion

Various Non-Surgical Therapies for Intermittent Exotropia

Indications for Surgery

The AAO PPP pediatric glass prescribing guideline

bull When hyperopia and esotropia coexist initial management includes full correction of the cycloplegic refractive error

bull Later reductions in the amount of correction may be appropriate based on the amount of esotropia and level of stereopsis at near and at distance with the full cycloplegic correction in place

Hyperopia associated with partly

of full accommodative esotropia

When hyperopia is associated with overt esotropia or ever large esophoria a full cycloplegic correction should be prescribed

The principle is to prescribed the maximum plus the patient will accept without degrading the visual acuity

Generally this equals the full cyclopentolate or atropine refration upto the age 2 years because the patients enviroment is close at hand and subjective tests are not possible

In older children 050 ndash 100 D should be subtracted In some cases of acc ET an extra + 050 D could

make some difference to the strabismus

Undercorrection amp Undercorrection amp overcorrectionovercorrection

Undercorrect myopia in accommodative ET rarely tolerated

Slight overcorrection of myopia in IXTOptical overcorrection or under

correction in treatment of amblyopia(penalization)

تاری ساله اي با شكايت 60خانم دید و دو بینی در نگاه نزدیک علیرغم

استفاده از عینک نزدیک مراجعه کرده است قدرت و ساخت عینک نزدیک

ایرادی ندارد در روبرو و دور ارتو است

ر اه حل پیشنهادی شما چیست

ساله ای با انحراف چشم و دو بینی از 33بیمار هفته قبل مراجعه کرده است 2

Ophthalmic Prism

Ali Akbar SabermoghaddamAssociated professor of OphthalmologyEye research center amp Khatam eye hospital MUMS

Prisms bend rays toward the base

PRISMS

P

cm displacement

1 m=

Prismatic Power (P)

apex

base

100 cm

X cm

Ophthalmic PrismPrismatic power

Ophthalmic Prism

bull Prisms function by bending rays of light towards the base of the prism bull The degree of bending of light depends upon the angle of incidence of light and the prismatic power

Ophthalmic prisms have been used in the treatment of binocular problems for more than 100 years

Ophthalmic Prism

Corrective Prism1 Ground ndash In Prism2 Fresnel ndash On Prism (Press-on Prisms)

Ophthalmic PrismPRESCRIBING INDUCED PRISM BY INTENTIONALLY

DISPLACING THE OPTICAL CENTERS Light traveling through the optical center of a lens encounters

no prismatic power and passes through undeviated However as the distance from the optical center increases

increasing prismatic power is encountered Prentices rule This is defined algebraically using the formula Δ = hD where Δ = prism diopters h = distance from the

optical center in centimeters and D= power of the lens in diopters

Of note the direction of displacement of light depends on whether the lens is of minus or plus power

- Minus lenses function as prisms held apex to apex that is as if the apex

of the prism were at the optical center of the lens - In other words a ray of light traveling above the optical

center encounters base-up prism power and a ray traveling below

the optical center encounters base-down prism

In the mid 1960s the 150-year-old Fresnel principle was applied to ophthalmic prisms for the first time The first ophthalmic Fresnel prism known as the wafer prism was molded of an acrylic resin making it much lighter and thinner than the corresponding powers of conventional prisms thus extending the useful range of prism powers

In 1970 the Press-OnTM prism a Fresnel-principle prism molded in flexible plastic was introduced to ophthalmologists This thin light membrane prism had the advantage of conforming and adhering to a smooth surface and thus could be affixed directly to a plano or basecurved correcting spectacle lens

Ophthalmic Prism

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

bull Part time patching of the non-deviating eye for four to six hours daily may convert an intermittent exotropia to a phoria

bull Although the benefit is usually temporary occlusion can be used to postpone surgical intervention in responsive patients

bull Alternate occlusion may be used in patients with equal fixation preferences

bull Initially the results are evaluated after 4 months of occlusionbull If the angle of deviation is decreased the occlusion should be

continued and assessment made every 4 months until no further change occurs

bull In case there is no improvement for 4 months it is discontinued

Occlusion

Various Non-Surgical Therapies for Intermittent Exotropia

Indications for Surgery

The AAO PPP pediatric glass prescribing guideline

bull When hyperopia and esotropia coexist initial management includes full correction of the cycloplegic refractive error

bull Later reductions in the amount of correction may be appropriate based on the amount of esotropia and level of stereopsis at near and at distance with the full cycloplegic correction in place

Hyperopia associated with partly

of full accommodative esotropia

When hyperopia is associated with overt esotropia or ever large esophoria a full cycloplegic correction should be prescribed

The principle is to prescribed the maximum plus the patient will accept without degrading the visual acuity

Generally this equals the full cyclopentolate or atropine refration upto the age 2 years because the patients enviroment is close at hand and subjective tests are not possible

In older children 050 ndash 100 D should be subtracted In some cases of acc ET an extra + 050 D could

make some difference to the strabismus

Undercorrection amp Undercorrection amp overcorrectionovercorrection

Undercorrect myopia in accommodative ET rarely tolerated

Slight overcorrection of myopia in IXTOptical overcorrection or under

correction in treatment of amblyopia(penalization)

تاری ساله اي با شكايت 60خانم دید و دو بینی در نگاه نزدیک علیرغم

استفاده از عینک نزدیک مراجعه کرده است قدرت و ساخت عینک نزدیک

ایرادی ندارد در روبرو و دور ارتو است

ر اه حل پیشنهادی شما چیست

ساله ای با انحراف چشم و دو بینی از 33بیمار هفته قبل مراجعه کرده است 2

Ophthalmic Prism

Ali Akbar SabermoghaddamAssociated professor of OphthalmologyEye research center amp Khatam eye hospital MUMS

Prisms bend rays toward the base

PRISMS

P

cm displacement

1 m=

Prismatic Power (P)

apex

base

100 cm

X cm

Ophthalmic PrismPrismatic power

Ophthalmic Prism

bull Prisms function by bending rays of light towards the base of the prism bull The degree of bending of light depends upon the angle of incidence of light and the prismatic power

Ophthalmic prisms have been used in the treatment of binocular problems for more than 100 years

Ophthalmic Prism

Corrective Prism1 Ground ndash In Prism2 Fresnel ndash On Prism (Press-on Prisms)

Ophthalmic PrismPRESCRIBING INDUCED PRISM BY INTENTIONALLY

DISPLACING THE OPTICAL CENTERS Light traveling through the optical center of a lens encounters

no prismatic power and passes through undeviated However as the distance from the optical center increases

increasing prismatic power is encountered Prentices rule This is defined algebraically using the formula Δ = hD where Δ = prism diopters h = distance from the

optical center in centimeters and D= power of the lens in diopters

Of note the direction of displacement of light depends on whether the lens is of minus or plus power

- Minus lenses function as prisms held apex to apex that is as if the apex

of the prism were at the optical center of the lens - In other words a ray of light traveling above the optical

center encounters base-up prism power and a ray traveling below

the optical center encounters base-down prism

In the mid 1960s the 150-year-old Fresnel principle was applied to ophthalmic prisms for the first time The first ophthalmic Fresnel prism known as the wafer prism was molded of an acrylic resin making it much lighter and thinner than the corresponding powers of conventional prisms thus extending the useful range of prism powers

In 1970 the Press-OnTM prism a Fresnel-principle prism molded in flexible plastic was introduced to ophthalmologists This thin light membrane prism had the advantage of conforming and adhering to a smooth surface and thus could be affixed directly to a plano or basecurved correcting spectacle lens

Ophthalmic Prism

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Various Non-Surgical Therapies for Intermittent Exotropia

Indications for Surgery

The AAO PPP pediatric glass prescribing guideline

bull When hyperopia and esotropia coexist initial management includes full correction of the cycloplegic refractive error

bull Later reductions in the amount of correction may be appropriate based on the amount of esotropia and level of stereopsis at near and at distance with the full cycloplegic correction in place

Hyperopia associated with partly

of full accommodative esotropia

When hyperopia is associated with overt esotropia or ever large esophoria a full cycloplegic correction should be prescribed

The principle is to prescribed the maximum plus the patient will accept without degrading the visual acuity

Generally this equals the full cyclopentolate or atropine refration upto the age 2 years because the patients enviroment is close at hand and subjective tests are not possible

In older children 050 ndash 100 D should be subtracted In some cases of acc ET an extra + 050 D could

make some difference to the strabismus

Undercorrection amp Undercorrection amp overcorrectionovercorrection

Undercorrect myopia in accommodative ET rarely tolerated

Slight overcorrection of myopia in IXTOptical overcorrection or under

correction in treatment of amblyopia(penalization)

تاری ساله اي با شكايت 60خانم دید و دو بینی در نگاه نزدیک علیرغم

استفاده از عینک نزدیک مراجعه کرده است قدرت و ساخت عینک نزدیک

ایرادی ندارد در روبرو و دور ارتو است

ر اه حل پیشنهادی شما چیست

ساله ای با انحراف چشم و دو بینی از 33بیمار هفته قبل مراجعه کرده است 2

Ophthalmic Prism

Ali Akbar SabermoghaddamAssociated professor of OphthalmologyEye research center amp Khatam eye hospital MUMS

Prisms bend rays toward the base

PRISMS

P

cm displacement

1 m=

Prismatic Power (P)

apex

base

100 cm

X cm

Ophthalmic PrismPrismatic power

Ophthalmic Prism

bull Prisms function by bending rays of light towards the base of the prism bull The degree of bending of light depends upon the angle of incidence of light and the prismatic power

Ophthalmic prisms have been used in the treatment of binocular problems for more than 100 years

Ophthalmic Prism

Corrective Prism1 Ground ndash In Prism2 Fresnel ndash On Prism (Press-on Prisms)

Ophthalmic PrismPRESCRIBING INDUCED PRISM BY INTENTIONALLY

DISPLACING THE OPTICAL CENTERS Light traveling through the optical center of a lens encounters

no prismatic power and passes through undeviated However as the distance from the optical center increases

increasing prismatic power is encountered Prentices rule This is defined algebraically using the formula Δ = hD where Δ = prism diopters h = distance from the

optical center in centimeters and D= power of the lens in diopters

Of note the direction of displacement of light depends on whether the lens is of minus or plus power

- Minus lenses function as prisms held apex to apex that is as if the apex

of the prism were at the optical center of the lens - In other words a ray of light traveling above the optical

center encounters base-up prism power and a ray traveling below

the optical center encounters base-down prism

In the mid 1960s the 150-year-old Fresnel principle was applied to ophthalmic prisms for the first time The first ophthalmic Fresnel prism known as the wafer prism was molded of an acrylic resin making it much lighter and thinner than the corresponding powers of conventional prisms thus extending the useful range of prism powers

In 1970 the Press-OnTM prism a Fresnel-principle prism molded in flexible plastic was introduced to ophthalmologists This thin light membrane prism had the advantage of conforming and adhering to a smooth surface and thus could be affixed directly to a plano or basecurved correcting spectacle lens

Ophthalmic Prism

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Indications for Surgery

The AAO PPP pediatric glass prescribing guideline

bull When hyperopia and esotropia coexist initial management includes full correction of the cycloplegic refractive error

bull Later reductions in the amount of correction may be appropriate based on the amount of esotropia and level of stereopsis at near and at distance with the full cycloplegic correction in place

Hyperopia associated with partly

of full accommodative esotropia

When hyperopia is associated with overt esotropia or ever large esophoria a full cycloplegic correction should be prescribed

The principle is to prescribed the maximum plus the patient will accept without degrading the visual acuity

Generally this equals the full cyclopentolate or atropine refration upto the age 2 years because the patients enviroment is close at hand and subjective tests are not possible

In older children 050 ndash 100 D should be subtracted In some cases of acc ET an extra + 050 D could

make some difference to the strabismus

Undercorrection amp Undercorrection amp overcorrectionovercorrection

Undercorrect myopia in accommodative ET rarely tolerated

Slight overcorrection of myopia in IXTOptical overcorrection or under

correction in treatment of amblyopia(penalization)

تاری ساله اي با شكايت 60خانم دید و دو بینی در نگاه نزدیک علیرغم

استفاده از عینک نزدیک مراجعه کرده است قدرت و ساخت عینک نزدیک

ایرادی ندارد در روبرو و دور ارتو است

ر اه حل پیشنهادی شما چیست

ساله ای با انحراف چشم و دو بینی از 33بیمار هفته قبل مراجعه کرده است 2

Ophthalmic Prism

Ali Akbar SabermoghaddamAssociated professor of OphthalmologyEye research center amp Khatam eye hospital MUMS

Prisms bend rays toward the base

PRISMS

P

cm displacement

1 m=

Prismatic Power (P)

apex

base

100 cm

X cm

Ophthalmic PrismPrismatic power

Ophthalmic Prism

bull Prisms function by bending rays of light towards the base of the prism bull The degree of bending of light depends upon the angle of incidence of light and the prismatic power

Ophthalmic prisms have been used in the treatment of binocular problems for more than 100 years

Ophthalmic Prism

Corrective Prism1 Ground ndash In Prism2 Fresnel ndash On Prism (Press-on Prisms)

Ophthalmic PrismPRESCRIBING INDUCED PRISM BY INTENTIONALLY

DISPLACING THE OPTICAL CENTERS Light traveling through the optical center of a lens encounters

no prismatic power and passes through undeviated However as the distance from the optical center increases

increasing prismatic power is encountered Prentices rule This is defined algebraically using the formula Δ = hD where Δ = prism diopters h = distance from the

optical center in centimeters and D= power of the lens in diopters

Of note the direction of displacement of light depends on whether the lens is of minus or plus power

- Minus lenses function as prisms held apex to apex that is as if the apex

of the prism were at the optical center of the lens - In other words a ray of light traveling above the optical

center encounters base-up prism power and a ray traveling below

the optical center encounters base-down prism

In the mid 1960s the 150-year-old Fresnel principle was applied to ophthalmic prisms for the first time The first ophthalmic Fresnel prism known as the wafer prism was molded of an acrylic resin making it much lighter and thinner than the corresponding powers of conventional prisms thus extending the useful range of prism powers

In 1970 the Press-OnTM prism a Fresnel-principle prism molded in flexible plastic was introduced to ophthalmologists This thin light membrane prism had the advantage of conforming and adhering to a smooth surface and thus could be affixed directly to a plano or basecurved correcting spectacle lens

Ophthalmic Prism

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

The AAO PPP pediatric glass prescribing guideline

bull When hyperopia and esotropia coexist initial management includes full correction of the cycloplegic refractive error

bull Later reductions in the amount of correction may be appropriate based on the amount of esotropia and level of stereopsis at near and at distance with the full cycloplegic correction in place

Hyperopia associated with partly

of full accommodative esotropia

When hyperopia is associated with overt esotropia or ever large esophoria a full cycloplegic correction should be prescribed

The principle is to prescribed the maximum plus the patient will accept without degrading the visual acuity

Generally this equals the full cyclopentolate or atropine refration upto the age 2 years because the patients enviroment is close at hand and subjective tests are not possible

In older children 050 ndash 100 D should be subtracted In some cases of acc ET an extra + 050 D could

make some difference to the strabismus

Undercorrection amp Undercorrection amp overcorrectionovercorrection

Undercorrect myopia in accommodative ET rarely tolerated

Slight overcorrection of myopia in IXTOptical overcorrection or under

correction in treatment of amblyopia(penalization)

تاری ساله اي با شكايت 60خانم دید و دو بینی در نگاه نزدیک علیرغم

استفاده از عینک نزدیک مراجعه کرده است قدرت و ساخت عینک نزدیک

ایرادی ندارد در روبرو و دور ارتو است

ر اه حل پیشنهادی شما چیست

ساله ای با انحراف چشم و دو بینی از 33بیمار هفته قبل مراجعه کرده است 2

Ophthalmic Prism

Ali Akbar SabermoghaddamAssociated professor of OphthalmologyEye research center amp Khatam eye hospital MUMS

Prisms bend rays toward the base

PRISMS

P

cm displacement

1 m=

Prismatic Power (P)

apex

base

100 cm

X cm

Ophthalmic PrismPrismatic power

Ophthalmic Prism

bull Prisms function by bending rays of light towards the base of the prism bull The degree of bending of light depends upon the angle of incidence of light and the prismatic power

Ophthalmic prisms have been used in the treatment of binocular problems for more than 100 years

Ophthalmic Prism

Corrective Prism1 Ground ndash In Prism2 Fresnel ndash On Prism (Press-on Prisms)

Ophthalmic PrismPRESCRIBING INDUCED PRISM BY INTENTIONALLY

DISPLACING THE OPTICAL CENTERS Light traveling through the optical center of a lens encounters

no prismatic power and passes through undeviated However as the distance from the optical center increases

increasing prismatic power is encountered Prentices rule This is defined algebraically using the formula Δ = hD where Δ = prism diopters h = distance from the

optical center in centimeters and D= power of the lens in diopters

Of note the direction of displacement of light depends on whether the lens is of minus or plus power

- Minus lenses function as prisms held apex to apex that is as if the apex

of the prism were at the optical center of the lens - In other words a ray of light traveling above the optical

center encounters base-up prism power and a ray traveling below

the optical center encounters base-down prism

In the mid 1960s the 150-year-old Fresnel principle was applied to ophthalmic prisms for the first time The first ophthalmic Fresnel prism known as the wafer prism was molded of an acrylic resin making it much lighter and thinner than the corresponding powers of conventional prisms thus extending the useful range of prism powers

In 1970 the Press-OnTM prism a Fresnel-principle prism molded in flexible plastic was introduced to ophthalmologists This thin light membrane prism had the advantage of conforming and adhering to a smooth surface and thus could be affixed directly to a plano or basecurved correcting spectacle lens

Ophthalmic Prism

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

bull When hyperopia and esotropia coexist initial management includes full correction of the cycloplegic refractive error

bull Later reductions in the amount of correction may be appropriate based on the amount of esotropia and level of stereopsis at near and at distance with the full cycloplegic correction in place

Hyperopia associated with partly

of full accommodative esotropia

When hyperopia is associated with overt esotropia or ever large esophoria a full cycloplegic correction should be prescribed

The principle is to prescribed the maximum plus the patient will accept without degrading the visual acuity

Generally this equals the full cyclopentolate or atropine refration upto the age 2 years because the patients enviroment is close at hand and subjective tests are not possible

In older children 050 ndash 100 D should be subtracted In some cases of acc ET an extra + 050 D could

make some difference to the strabismus

Undercorrection amp Undercorrection amp overcorrectionovercorrection

Undercorrect myopia in accommodative ET rarely tolerated

Slight overcorrection of myopia in IXTOptical overcorrection or under

correction in treatment of amblyopia(penalization)

تاری ساله اي با شكايت 60خانم دید و دو بینی در نگاه نزدیک علیرغم

استفاده از عینک نزدیک مراجعه کرده است قدرت و ساخت عینک نزدیک

ایرادی ندارد در روبرو و دور ارتو است

ر اه حل پیشنهادی شما چیست

ساله ای با انحراف چشم و دو بینی از 33بیمار هفته قبل مراجعه کرده است 2

Ophthalmic Prism

Ali Akbar SabermoghaddamAssociated professor of OphthalmologyEye research center amp Khatam eye hospital MUMS

Prisms bend rays toward the base

PRISMS

P

cm displacement

1 m=

Prismatic Power (P)

apex

base

100 cm

X cm

Ophthalmic PrismPrismatic power

Ophthalmic Prism

bull Prisms function by bending rays of light towards the base of the prism bull The degree of bending of light depends upon the angle of incidence of light and the prismatic power

Ophthalmic prisms have been used in the treatment of binocular problems for more than 100 years

Ophthalmic Prism

Corrective Prism1 Ground ndash In Prism2 Fresnel ndash On Prism (Press-on Prisms)

Ophthalmic PrismPRESCRIBING INDUCED PRISM BY INTENTIONALLY

DISPLACING THE OPTICAL CENTERS Light traveling through the optical center of a lens encounters

no prismatic power and passes through undeviated However as the distance from the optical center increases

increasing prismatic power is encountered Prentices rule This is defined algebraically using the formula Δ = hD where Δ = prism diopters h = distance from the

optical center in centimeters and D= power of the lens in diopters

Of note the direction of displacement of light depends on whether the lens is of minus or plus power

- Minus lenses function as prisms held apex to apex that is as if the apex

of the prism were at the optical center of the lens - In other words a ray of light traveling above the optical

center encounters base-up prism power and a ray traveling below

the optical center encounters base-down prism

In the mid 1960s the 150-year-old Fresnel principle was applied to ophthalmic prisms for the first time The first ophthalmic Fresnel prism known as the wafer prism was molded of an acrylic resin making it much lighter and thinner than the corresponding powers of conventional prisms thus extending the useful range of prism powers

In 1970 the Press-OnTM prism a Fresnel-principle prism molded in flexible plastic was introduced to ophthalmologists This thin light membrane prism had the advantage of conforming and adhering to a smooth surface and thus could be affixed directly to a plano or basecurved correcting spectacle lens

Ophthalmic Prism

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Hyperopia associated with partly

of full accommodative esotropia

When hyperopia is associated with overt esotropia or ever large esophoria a full cycloplegic correction should be prescribed

The principle is to prescribed the maximum plus the patient will accept without degrading the visual acuity

Generally this equals the full cyclopentolate or atropine refration upto the age 2 years because the patients enviroment is close at hand and subjective tests are not possible

In older children 050 ndash 100 D should be subtracted In some cases of acc ET an extra + 050 D could

make some difference to the strabismus

Undercorrection amp Undercorrection amp overcorrectionovercorrection

Undercorrect myopia in accommodative ET rarely tolerated

Slight overcorrection of myopia in IXTOptical overcorrection or under

correction in treatment of amblyopia(penalization)

تاری ساله اي با شكايت 60خانم دید و دو بینی در نگاه نزدیک علیرغم

استفاده از عینک نزدیک مراجعه کرده است قدرت و ساخت عینک نزدیک

ایرادی ندارد در روبرو و دور ارتو است

ر اه حل پیشنهادی شما چیست

ساله ای با انحراف چشم و دو بینی از 33بیمار هفته قبل مراجعه کرده است 2

Ophthalmic Prism

Ali Akbar SabermoghaddamAssociated professor of OphthalmologyEye research center amp Khatam eye hospital MUMS

Prisms bend rays toward the base

PRISMS

P

cm displacement

1 m=

Prismatic Power (P)

apex

base

100 cm

X cm

Ophthalmic PrismPrismatic power

Ophthalmic Prism

bull Prisms function by bending rays of light towards the base of the prism bull The degree of bending of light depends upon the angle of incidence of light and the prismatic power

Ophthalmic prisms have been used in the treatment of binocular problems for more than 100 years

Ophthalmic Prism

Corrective Prism1 Ground ndash In Prism2 Fresnel ndash On Prism (Press-on Prisms)

Ophthalmic PrismPRESCRIBING INDUCED PRISM BY INTENTIONALLY

DISPLACING THE OPTICAL CENTERS Light traveling through the optical center of a lens encounters

no prismatic power and passes through undeviated However as the distance from the optical center increases

increasing prismatic power is encountered Prentices rule This is defined algebraically using the formula Δ = hD where Δ = prism diopters h = distance from the

optical center in centimeters and D= power of the lens in diopters

Of note the direction of displacement of light depends on whether the lens is of minus or plus power

- Minus lenses function as prisms held apex to apex that is as if the apex

of the prism were at the optical center of the lens - In other words a ray of light traveling above the optical

center encounters base-up prism power and a ray traveling below

the optical center encounters base-down prism

In the mid 1960s the 150-year-old Fresnel principle was applied to ophthalmic prisms for the first time The first ophthalmic Fresnel prism known as the wafer prism was molded of an acrylic resin making it much lighter and thinner than the corresponding powers of conventional prisms thus extending the useful range of prism powers

In 1970 the Press-OnTM prism a Fresnel-principle prism molded in flexible plastic was introduced to ophthalmologists This thin light membrane prism had the advantage of conforming and adhering to a smooth surface and thus could be affixed directly to a plano or basecurved correcting spectacle lens

Ophthalmic Prism

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Undercorrection amp Undercorrection amp overcorrectionovercorrection

Undercorrect myopia in accommodative ET rarely tolerated

Slight overcorrection of myopia in IXTOptical overcorrection or under

correction in treatment of amblyopia(penalization)

تاری ساله اي با شكايت 60خانم دید و دو بینی در نگاه نزدیک علیرغم

استفاده از عینک نزدیک مراجعه کرده است قدرت و ساخت عینک نزدیک

ایرادی ندارد در روبرو و دور ارتو است

ر اه حل پیشنهادی شما چیست

ساله ای با انحراف چشم و دو بینی از 33بیمار هفته قبل مراجعه کرده است 2

Ophthalmic Prism

Ali Akbar SabermoghaddamAssociated professor of OphthalmologyEye research center amp Khatam eye hospital MUMS

Prisms bend rays toward the base

PRISMS

P

cm displacement

1 m=

Prismatic Power (P)

apex

base

100 cm

X cm

Ophthalmic PrismPrismatic power

Ophthalmic Prism

bull Prisms function by bending rays of light towards the base of the prism bull The degree of bending of light depends upon the angle of incidence of light and the prismatic power

Ophthalmic prisms have been used in the treatment of binocular problems for more than 100 years

Ophthalmic Prism

Corrective Prism1 Ground ndash In Prism2 Fresnel ndash On Prism (Press-on Prisms)

Ophthalmic PrismPRESCRIBING INDUCED PRISM BY INTENTIONALLY

DISPLACING THE OPTICAL CENTERS Light traveling through the optical center of a lens encounters

no prismatic power and passes through undeviated However as the distance from the optical center increases

increasing prismatic power is encountered Prentices rule This is defined algebraically using the formula Δ = hD where Δ = prism diopters h = distance from the

optical center in centimeters and D= power of the lens in diopters

Of note the direction of displacement of light depends on whether the lens is of minus or plus power

- Minus lenses function as prisms held apex to apex that is as if the apex

of the prism were at the optical center of the lens - In other words a ray of light traveling above the optical

center encounters base-up prism power and a ray traveling below

the optical center encounters base-down prism

In the mid 1960s the 150-year-old Fresnel principle was applied to ophthalmic prisms for the first time The first ophthalmic Fresnel prism known as the wafer prism was molded of an acrylic resin making it much lighter and thinner than the corresponding powers of conventional prisms thus extending the useful range of prism powers

In 1970 the Press-OnTM prism a Fresnel-principle prism molded in flexible plastic was introduced to ophthalmologists This thin light membrane prism had the advantage of conforming and adhering to a smooth surface and thus could be affixed directly to a plano or basecurved correcting spectacle lens

Ophthalmic Prism

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

تاری ساله اي با شكايت 60خانم دید و دو بینی در نگاه نزدیک علیرغم

استفاده از عینک نزدیک مراجعه کرده است قدرت و ساخت عینک نزدیک

ایرادی ندارد در روبرو و دور ارتو است

ر اه حل پیشنهادی شما چیست

ساله ای با انحراف چشم و دو بینی از 33بیمار هفته قبل مراجعه کرده است 2

Ophthalmic Prism

Ali Akbar SabermoghaddamAssociated professor of OphthalmologyEye research center amp Khatam eye hospital MUMS

Prisms bend rays toward the base

PRISMS

P

cm displacement

1 m=

Prismatic Power (P)

apex

base

100 cm

X cm

Ophthalmic PrismPrismatic power

Ophthalmic Prism

bull Prisms function by bending rays of light towards the base of the prism bull The degree of bending of light depends upon the angle of incidence of light and the prismatic power

Ophthalmic prisms have been used in the treatment of binocular problems for more than 100 years

Ophthalmic Prism

Corrective Prism1 Ground ndash In Prism2 Fresnel ndash On Prism (Press-on Prisms)

Ophthalmic PrismPRESCRIBING INDUCED PRISM BY INTENTIONALLY

DISPLACING THE OPTICAL CENTERS Light traveling through the optical center of a lens encounters

no prismatic power and passes through undeviated However as the distance from the optical center increases

increasing prismatic power is encountered Prentices rule This is defined algebraically using the formula Δ = hD where Δ = prism diopters h = distance from the

optical center in centimeters and D= power of the lens in diopters

Of note the direction of displacement of light depends on whether the lens is of minus or plus power

- Minus lenses function as prisms held apex to apex that is as if the apex

of the prism were at the optical center of the lens - In other words a ray of light traveling above the optical

center encounters base-up prism power and a ray traveling below

the optical center encounters base-down prism

In the mid 1960s the 150-year-old Fresnel principle was applied to ophthalmic prisms for the first time The first ophthalmic Fresnel prism known as the wafer prism was molded of an acrylic resin making it much lighter and thinner than the corresponding powers of conventional prisms thus extending the useful range of prism powers

In 1970 the Press-OnTM prism a Fresnel-principle prism molded in flexible plastic was introduced to ophthalmologists This thin light membrane prism had the advantage of conforming and adhering to a smooth surface and thus could be affixed directly to a plano or basecurved correcting spectacle lens

Ophthalmic Prism

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

ساله ای با انحراف چشم و دو بینی از 33بیمار هفته قبل مراجعه کرده است 2

Ophthalmic Prism

Ali Akbar SabermoghaddamAssociated professor of OphthalmologyEye research center amp Khatam eye hospital MUMS

Prisms bend rays toward the base

PRISMS

P

cm displacement

1 m=

Prismatic Power (P)

apex

base

100 cm

X cm

Ophthalmic PrismPrismatic power

Ophthalmic Prism

bull Prisms function by bending rays of light towards the base of the prism bull The degree of bending of light depends upon the angle of incidence of light and the prismatic power

Ophthalmic prisms have been used in the treatment of binocular problems for more than 100 years

Ophthalmic Prism

Corrective Prism1 Ground ndash In Prism2 Fresnel ndash On Prism (Press-on Prisms)

Ophthalmic PrismPRESCRIBING INDUCED PRISM BY INTENTIONALLY

DISPLACING THE OPTICAL CENTERS Light traveling through the optical center of a lens encounters

no prismatic power and passes through undeviated However as the distance from the optical center increases

increasing prismatic power is encountered Prentices rule This is defined algebraically using the formula Δ = hD where Δ = prism diopters h = distance from the

optical center in centimeters and D= power of the lens in diopters

Of note the direction of displacement of light depends on whether the lens is of minus or plus power

- Minus lenses function as prisms held apex to apex that is as if the apex

of the prism were at the optical center of the lens - In other words a ray of light traveling above the optical

center encounters base-up prism power and a ray traveling below

the optical center encounters base-down prism

In the mid 1960s the 150-year-old Fresnel principle was applied to ophthalmic prisms for the first time The first ophthalmic Fresnel prism known as the wafer prism was molded of an acrylic resin making it much lighter and thinner than the corresponding powers of conventional prisms thus extending the useful range of prism powers

In 1970 the Press-OnTM prism a Fresnel-principle prism molded in flexible plastic was introduced to ophthalmologists This thin light membrane prism had the advantage of conforming and adhering to a smooth surface and thus could be affixed directly to a plano or basecurved correcting spectacle lens

Ophthalmic Prism

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Ophthalmic Prism

Ali Akbar SabermoghaddamAssociated professor of OphthalmologyEye research center amp Khatam eye hospital MUMS

Prisms bend rays toward the base

PRISMS

P

cm displacement

1 m=

Prismatic Power (P)

apex

base

100 cm

X cm

Ophthalmic PrismPrismatic power

Ophthalmic Prism

bull Prisms function by bending rays of light towards the base of the prism bull The degree of bending of light depends upon the angle of incidence of light and the prismatic power

Ophthalmic prisms have been used in the treatment of binocular problems for more than 100 years

Ophthalmic Prism

Corrective Prism1 Ground ndash In Prism2 Fresnel ndash On Prism (Press-on Prisms)

Ophthalmic PrismPRESCRIBING INDUCED PRISM BY INTENTIONALLY

DISPLACING THE OPTICAL CENTERS Light traveling through the optical center of a lens encounters

no prismatic power and passes through undeviated However as the distance from the optical center increases

increasing prismatic power is encountered Prentices rule This is defined algebraically using the formula Δ = hD where Δ = prism diopters h = distance from the

optical center in centimeters and D= power of the lens in diopters

Of note the direction of displacement of light depends on whether the lens is of minus or plus power

- Minus lenses function as prisms held apex to apex that is as if the apex

of the prism were at the optical center of the lens - In other words a ray of light traveling above the optical

center encounters base-up prism power and a ray traveling below

the optical center encounters base-down prism

In the mid 1960s the 150-year-old Fresnel principle was applied to ophthalmic prisms for the first time The first ophthalmic Fresnel prism known as the wafer prism was molded of an acrylic resin making it much lighter and thinner than the corresponding powers of conventional prisms thus extending the useful range of prism powers

In 1970 the Press-OnTM prism a Fresnel-principle prism molded in flexible plastic was introduced to ophthalmologists This thin light membrane prism had the advantage of conforming and adhering to a smooth surface and thus could be affixed directly to a plano or basecurved correcting spectacle lens

Ophthalmic Prism

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Prisms bend rays toward the base

PRISMS

P

cm displacement

1 m=

Prismatic Power (P)

apex

base

100 cm

X cm

Ophthalmic PrismPrismatic power

Ophthalmic Prism

bull Prisms function by bending rays of light towards the base of the prism bull The degree of bending of light depends upon the angle of incidence of light and the prismatic power

Ophthalmic prisms have been used in the treatment of binocular problems for more than 100 years

Ophthalmic Prism

Corrective Prism1 Ground ndash In Prism2 Fresnel ndash On Prism (Press-on Prisms)

Ophthalmic PrismPRESCRIBING INDUCED PRISM BY INTENTIONALLY

DISPLACING THE OPTICAL CENTERS Light traveling through the optical center of a lens encounters

no prismatic power and passes through undeviated However as the distance from the optical center increases

increasing prismatic power is encountered Prentices rule This is defined algebraically using the formula Δ = hD where Δ = prism diopters h = distance from the

optical center in centimeters and D= power of the lens in diopters

Of note the direction of displacement of light depends on whether the lens is of minus or plus power

- Minus lenses function as prisms held apex to apex that is as if the apex

of the prism were at the optical center of the lens - In other words a ray of light traveling above the optical

center encounters base-up prism power and a ray traveling below

the optical center encounters base-down prism

In the mid 1960s the 150-year-old Fresnel principle was applied to ophthalmic prisms for the first time The first ophthalmic Fresnel prism known as the wafer prism was molded of an acrylic resin making it much lighter and thinner than the corresponding powers of conventional prisms thus extending the useful range of prism powers

In 1970 the Press-OnTM prism a Fresnel-principle prism molded in flexible plastic was introduced to ophthalmologists This thin light membrane prism had the advantage of conforming and adhering to a smooth surface and thus could be affixed directly to a plano or basecurved correcting spectacle lens

Ophthalmic Prism

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Ophthalmic PrismPrismatic power

Ophthalmic Prism

bull Prisms function by bending rays of light towards the base of the prism bull The degree of bending of light depends upon the angle of incidence of light and the prismatic power

Ophthalmic prisms have been used in the treatment of binocular problems for more than 100 years

Ophthalmic Prism

Corrective Prism1 Ground ndash In Prism2 Fresnel ndash On Prism (Press-on Prisms)

Ophthalmic PrismPRESCRIBING INDUCED PRISM BY INTENTIONALLY

DISPLACING THE OPTICAL CENTERS Light traveling through the optical center of a lens encounters

no prismatic power and passes through undeviated However as the distance from the optical center increases

increasing prismatic power is encountered Prentices rule This is defined algebraically using the formula Δ = hD where Δ = prism diopters h = distance from the

optical center in centimeters and D= power of the lens in diopters

Of note the direction of displacement of light depends on whether the lens is of minus or plus power

- Minus lenses function as prisms held apex to apex that is as if the apex

of the prism were at the optical center of the lens - In other words a ray of light traveling above the optical

center encounters base-up prism power and a ray traveling below

the optical center encounters base-down prism

In the mid 1960s the 150-year-old Fresnel principle was applied to ophthalmic prisms for the first time The first ophthalmic Fresnel prism known as the wafer prism was molded of an acrylic resin making it much lighter and thinner than the corresponding powers of conventional prisms thus extending the useful range of prism powers

In 1970 the Press-OnTM prism a Fresnel-principle prism molded in flexible plastic was introduced to ophthalmologists This thin light membrane prism had the advantage of conforming and adhering to a smooth surface and thus could be affixed directly to a plano or basecurved correcting spectacle lens

Ophthalmic Prism

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Ophthalmic Prism

bull Prisms function by bending rays of light towards the base of the prism bull The degree of bending of light depends upon the angle of incidence of light and the prismatic power

Ophthalmic prisms have been used in the treatment of binocular problems for more than 100 years

Ophthalmic Prism

Corrective Prism1 Ground ndash In Prism2 Fresnel ndash On Prism (Press-on Prisms)

Ophthalmic PrismPRESCRIBING INDUCED PRISM BY INTENTIONALLY

DISPLACING THE OPTICAL CENTERS Light traveling through the optical center of a lens encounters

no prismatic power and passes through undeviated However as the distance from the optical center increases

increasing prismatic power is encountered Prentices rule This is defined algebraically using the formula Δ = hD where Δ = prism diopters h = distance from the

optical center in centimeters and D= power of the lens in diopters

Of note the direction of displacement of light depends on whether the lens is of minus or plus power

- Minus lenses function as prisms held apex to apex that is as if the apex

of the prism were at the optical center of the lens - In other words a ray of light traveling above the optical

center encounters base-up prism power and a ray traveling below

the optical center encounters base-down prism

In the mid 1960s the 150-year-old Fresnel principle was applied to ophthalmic prisms for the first time The first ophthalmic Fresnel prism known as the wafer prism was molded of an acrylic resin making it much lighter and thinner than the corresponding powers of conventional prisms thus extending the useful range of prism powers

In 1970 the Press-OnTM prism a Fresnel-principle prism molded in flexible plastic was introduced to ophthalmologists This thin light membrane prism had the advantage of conforming and adhering to a smooth surface and thus could be affixed directly to a plano or basecurved correcting spectacle lens

Ophthalmic Prism

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Ophthalmic prisms have been used in the treatment of binocular problems for more than 100 years

Ophthalmic Prism

Corrective Prism1 Ground ndash In Prism2 Fresnel ndash On Prism (Press-on Prisms)

Ophthalmic PrismPRESCRIBING INDUCED PRISM BY INTENTIONALLY

DISPLACING THE OPTICAL CENTERS Light traveling through the optical center of a lens encounters

no prismatic power and passes through undeviated However as the distance from the optical center increases

increasing prismatic power is encountered Prentices rule This is defined algebraically using the formula Δ = hD where Δ = prism diopters h = distance from the

optical center in centimeters and D= power of the lens in diopters

Of note the direction of displacement of light depends on whether the lens is of minus or plus power

- Minus lenses function as prisms held apex to apex that is as if the apex

of the prism were at the optical center of the lens - In other words a ray of light traveling above the optical

center encounters base-up prism power and a ray traveling below

the optical center encounters base-down prism

In the mid 1960s the 150-year-old Fresnel principle was applied to ophthalmic prisms for the first time The first ophthalmic Fresnel prism known as the wafer prism was molded of an acrylic resin making it much lighter and thinner than the corresponding powers of conventional prisms thus extending the useful range of prism powers

In 1970 the Press-OnTM prism a Fresnel-principle prism molded in flexible plastic was introduced to ophthalmologists This thin light membrane prism had the advantage of conforming and adhering to a smooth surface and thus could be affixed directly to a plano or basecurved correcting spectacle lens

Ophthalmic Prism

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Ophthalmic Prism

Corrective Prism1 Ground ndash In Prism2 Fresnel ndash On Prism (Press-on Prisms)

Ophthalmic PrismPRESCRIBING INDUCED PRISM BY INTENTIONALLY

DISPLACING THE OPTICAL CENTERS Light traveling through the optical center of a lens encounters

no prismatic power and passes through undeviated However as the distance from the optical center increases

increasing prismatic power is encountered Prentices rule This is defined algebraically using the formula Δ = hD where Δ = prism diopters h = distance from the

optical center in centimeters and D= power of the lens in diopters

Of note the direction of displacement of light depends on whether the lens is of minus or plus power

- Minus lenses function as prisms held apex to apex that is as if the apex

of the prism were at the optical center of the lens - In other words a ray of light traveling above the optical

center encounters base-up prism power and a ray traveling below

the optical center encounters base-down prism

In the mid 1960s the 150-year-old Fresnel principle was applied to ophthalmic prisms for the first time The first ophthalmic Fresnel prism known as the wafer prism was molded of an acrylic resin making it much lighter and thinner than the corresponding powers of conventional prisms thus extending the useful range of prism powers

In 1970 the Press-OnTM prism a Fresnel-principle prism molded in flexible plastic was introduced to ophthalmologists This thin light membrane prism had the advantage of conforming and adhering to a smooth surface and thus could be affixed directly to a plano or basecurved correcting spectacle lens

Ophthalmic Prism

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Ophthalmic PrismPRESCRIBING INDUCED PRISM BY INTENTIONALLY

DISPLACING THE OPTICAL CENTERS Light traveling through the optical center of a lens encounters

no prismatic power and passes through undeviated However as the distance from the optical center increases

increasing prismatic power is encountered Prentices rule This is defined algebraically using the formula Δ = hD where Δ = prism diopters h = distance from the

optical center in centimeters and D= power of the lens in diopters

Of note the direction of displacement of light depends on whether the lens is of minus or plus power

- Minus lenses function as prisms held apex to apex that is as if the apex

of the prism were at the optical center of the lens - In other words a ray of light traveling above the optical

center encounters base-up prism power and a ray traveling below

the optical center encounters base-down prism

In the mid 1960s the 150-year-old Fresnel principle was applied to ophthalmic prisms for the first time The first ophthalmic Fresnel prism known as the wafer prism was molded of an acrylic resin making it much lighter and thinner than the corresponding powers of conventional prisms thus extending the useful range of prism powers

In 1970 the Press-OnTM prism a Fresnel-principle prism molded in flexible plastic was introduced to ophthalmologists This thin light membrane prism had the advantage of conforming and adhering to a smooth surface and thus could be affixed directly to a plano or basecurved correcting spectacle lens

Ophthalmic Prism

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

In the mid 1960s the 150-year-old Fresnel principle was applied to ophthalmic prisms for the first time The first ophthalmic Fresnel prism known as the wafer prism was molded of an acrylic resin making it much lighter and thinner than the corresponding powers of conventional prisms thus extending the useful range of prism powers

In 1970 the Press-OnTM prism a Fresnel-principle prism molded in flexible plastic was introduced to ophthalmologists This thin light membrane prism had the advantage of conforming and adhering to a smooth surface and thus could be affixed directly to a plano or basecurved correcting spectacle lens

Ophthalmic Prism

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Ophthalmic Prism

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Fresnel ndash On Prism

bull Fresnel prisms are constructed as a series of very narrow adjacent prisms on a thin sheet of plastic bull The prism is flexible enabling it to conform to the base curve of the spectacle lens bull The commercially available powers of Fresnel prisms (in increments of 1 from 1 to 10 a power of 12 and in increments of 5 from 15 to 40)

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Internal ReflectionColor SeparationMagnificationVisual acuityFusion and stereopsis

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Ophthalmic Prism

FRESNEL PRISMS The prism is applied by pressing the smooth

surface of the prism against the back surface of the spectacle lens while the lens is submerged in water

Disadvantage of Fresnel prisms is that higher-power

- Introduce glare and chromatic aberration - Significant decline in vision - Minimal decline in visual acuity when using

Fresnel prisms of 12 prism diopters or less

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Ophthalmic PrismTerminologya Relieving Prism bull Action ndash Reduces the demand for controlling

fusional vergenceb Inverse Prism bull Action ndash Increases the demand for controlling

fusional vergencec Yoked Prism bull Action ndash Directs the eyes into a specific gaze

directiond Sector Regional Prism bull Action ndash Reduces the demand for controlling

vergence in more than 1 gaze

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Ophthalmic PrismIndication 1- Strabismus - Comitant - Non - Comitant (Diplopia) 2 - Symptomatic heterophorias Convergence

training for exodeviation 3 ndash presbyopia with symptomatic CI 4 - Nystagmus 5- Amblyopia 6- Cosmetic

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Ophthalmic PrismPrism For Deviations

1 Exo Base-In (BI) over either eye2 Eso Base-Out (BO) over either eye3 RHT

- Base-Down (BD) over right eye - Base-Up (BU) over left eye

4 LHT - BD over left eye - BU over right eye

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Ophthalmic Prism Prism For Head postures

1 Left face turn Yoked prism base left

2 Right face turn Yoked prism base right

3 Chin elevation Yoked prism (BU)

4 Chin depression Yoked prism(BD)

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Chin Depression

Yoked prism(BD)

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Ophthalmic Prism

Adverse ( Reverse) Prism Indications

1To ignore the diplopic image2During convergence training for

exodeviation (BO Prism) 3Cosmetics for patients who has very

poor acuity in one eye or are poor surgical candidates (approximately 15 prescribed

4Strengthening of the weak muscle

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

1- Strengthening of the weak muscle

2- Prevent Contractures of antagonist

Adverse Prism

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Inoperable strabismus

Adverse Prism

Cosmetic

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Relieving Prism In order to move the image to where the eye is

looking thus restoring fixation and binocular vision For diplopia Base of the prism is placed over the weak (or

paralyzed muscles)

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Relieving Prism

Surgical over and under-correction

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Relieving Prism

Mild Amblyopia

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Relieving Prism

Nystagmus

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Relieving Prism

DIPLOPIA Nerve palsies

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

DIPLOPIA

Myasthenia Gravis Multiple Sclerosis Graves Disease

OBLIQUE PRISMS

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

DIPLOPIA

RHT

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Symptomatic Heterophoria

Prismatic correction of exophoria

Relieving Prism

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Prism for Symptomatic Heterophoria

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Prism for Symptomatic Heterophoria sheardrsquos criterion Formula prism needed=23 (phoria)

ndash 13 (compensating fusional vergence)

If a patient has 6 exophoria and base-out prism (BO) to blure is 623 X6 -13X6=2 you would prescribe 2 base-in for this patient

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Prism for Other Medical

- Bed-ridden patients

- Ankylosing spondylitis - Other postural deformities

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Ophthalmic PrismCLINICAL APPLICATIONS In patients with tropias (small comitant deviations) To ease asthenopia in patients with phorias Small-angle strabismus following intraocular surgery and Residual deviations following strabismus surgery In most cases of superior oblique palsy many patients will

respond well to a small amount of vertical prism with improvement in double vision and in head tilt as well

Intermittent exotropia (to partially correct the angle of misalignment and decrease the fusional convergence requirement)

convergence insufficiency (best used with separate reading glasses to avoid introducing esotropia at distance)

divergence insufficiency (best used at distance only) Anisometropia in the reading position (best treated with hellip

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Ophthalmic PrismOTHER CLINICAL USES OF PRISM Prisms have been incorporated into contact lenses as a means

of correcting vertical diplopia but this method is only rarely used

In some cases prisms may be prescribed as a form of eye lsquoexercisersquo For example in convergence insufficiency the patient might be prescribed base out prism over both eyes to increase the exotropia at near

This is typically provided as a removable Fresnel prism that is worn part of the day with the goal of making the patient more comfortable the rest of the day when the prism is not worn

Prisms may be used in the setting of nystagmus to improve head positions and to improve acuity[To correct head positions prisms are lsquoyokedrsquo to shift the image into the null zone area For example a patient who has a right head turn and a null point in left gaze would be treated with base-out prism in front of the right eye and base-in prism in front of

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure Estimating prism power A good way to arrive at a starting

prism power is to take the higher power prism measurement and add one-half of the lower power measurement

For example take a hypothetical patient with 20 prism diopters of esotropia and 10 PD of left hypertropia The higher power measurement (20) is added to half the lower power measurement (10 divide 2 = 5) Therefore a 25-PD handheld prism is selected

Testing the prism This prism is then placed before the nondominant eye Assuming the left eye is nondominant the 25-PD handheld prism would be placed with the base out and slightly down in front of the left eye to correct the combined esotropia and left hypertropia

This prism is rotated slowly clockwise or counter-clockwise until the patient notes that the two images are fused

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMS

The Procedure If the patient is unable to fuse another prism is selected

(start with a prism one increment higher or lowermdashin this case either a 30-PD or 20-PD and the process is repeated until fusion occurs

Prescribing the prism A wax pencil is then used to draw a line directly on the outside of the spectacles using the base of the handheld prism as a guide The clinician writes a prescription that includes the prism power and a statement regarding the orientation of the prism For the above example the prescription would read ldquo25-PD Fresnel prism base out and down as marked

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Ophthalmic PrismOBLIQUE PRISMS Oblique prisms are required when trying to prescribe a single

Fresnel prism for a combined vertical and horizontal deviation Vector addition is used to combine horizontal and vertical prism For example combining 5 Δ base up with 5 Δ base out may be solved using the Pythagorean theorem (for a right triangle with sides a b andc with c the hypotenuse a2 + b2 = c2) In this case 52 + 52 = c2 = 50 so c = radic50 Thus 71 Δ of Fresnel prism may be prescribed base up and out in the 45deg meridian More complex combinations of vertical and horizontal prisms may be determined by applying basic trigonometric relationships of right triangles or more practically by measuring the combination of vertical and horizontal prism in the lensmeter When prescribing a combination of vertical and horizontal prism for ground-in prism these calculations are not necessary as most opticians prefer to be given the horizontal and vertical components separately

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

OBLIQUE PRISMS

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

How to Prescribe a Prism for Combined Vertical and Horizontal StrabismusOBLIQUE PRISMSCASE ONE A 75-year-old woman with Graves disease

complained of diplopia Motility testing showed 25 PD of left hypertropia and 10 PD

of esotropia A 30-PD handheld prism was chosen (25 + half of 10) Held base down and out in front of the nondominant left eye The prism was rotated slightly clockwise and counter-

clockwise until fusion occurred The outside of the glasses were marked with a wax pencil

along the base of the prism An optician applied a 30-PD Fresnel prism with the base

oriented as marked The prism relieved the diplopia in primary gaze

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

How to Prescribe a Prism for Combined Vertical

and Horizontal Strabismus (OBLIQUE PRISMS)

CASE TWO A 52-year-old woman developed incomitant strabismus with binocular oblique diplopia following an embolization procedure for a dural arteriovenous fistula

Motility testing showed 10 PD of exotropia and 8 PD of left hypotropia in primary gaze

A 15-PD handheld prism was chosen (10 + half of 8 rounded off to the closest available Fresnel prism power) held base in and up in front of the left eye

Then rotated in a manner similar to that described above until fusion occurred

The glasses were marked with a wax pencil The patient took the marked glasses to an optician for

application of a 15-PD Fresnel prism base in and up to the left spectacle lens

The prism corrected the diplopia in primary gaze

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Ophthalmic PrismSLAB-OFF PRISM Patients who have anisometropia may suffer from diplopia or

asthenopia when the line of sight does not pass through the optical centers of their spectacles

This occurs because the displacement induces a net prismatic effect In general most patients are able to use fusional abilities to adapt to

the induced horizontal prism However vertical gaze is often quite problematic For example a

patient who has a refractive error of ndash300 OD and +100 OS will have induced prism when looking away from the optical center If this patient looks 1 cm below the optical centers to read the induced prismatic power will be 3Δ (1 cm times3 D) of base-down prism on the right and 1Δ (1 cm times1 D) of base-up prism on the left giving a net prismatic effect of 4Δ base down on the right (base up on the left) Cover testing would reveal a 4Δ left hypertropia in the reading position

There are several options for treating the vertical prismatic effects of anisometropia Contact lenses may be hellip

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Ophthalmic PrismMEASURING PRISM IN SPECTACLES The effective prism power in spectacle lenses is the combination of

ground-in prism plus prism induced by displacement of the optical centers To measure the amount of effective prism in spectacles ask the patient to fixate on your own eye then mark the point where line of sight intersects the lens using a felt tip marker (The line of sight is the line connecting the object of regard with the center of the pupil) The prism power at this location is the effective prism power (This may or may not be the intended prism power depending on whether or not the optician correctly placed the optical center of the lens in front of the patients pupil) The glasses are then positioned on the lensmeter such that the mark on the lens is centered within the lensmeter port If no prism is present the mires representing the two cylindrical axes will intersect in the center of the lensmeter reticle If prism is present in the lens the mires will cross at a location

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Ophthalmic PrismWRITING A PRISM PRESCRIPTION When prescribing prisms it is important to specify the amount

and direction of the prism in addition to the lens or lenses into which the prism should be incorporated Fresnel prisms are useful as a trial before grinding the prism into the spectacle lens In our experience it is best if Fresnel prisms are placed in the office or by a trusted optician errors in positioning are frequent when the prisms are placed by inexperienced individuals

Prescriptions requiring prism must be written with special care to avoid errors It is advisable to communicate directly with the optician for particularly complex prescriptions For combined vertical and horizontal deviations requiring oblique Fresnel prisms the axis of the base must be specified using degrees as for astigmatic lenses However the astigmatic axis allows for two positions of the base that is lsquo10Δ base 30degrsquo could be interpreted as lsquo10Δ base up-and-out in the 30deg meridianrsquo oras lsquo10Δ base down-and-in

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Indication - Comitant Strabismus - Non - Comitant Strabismus (Diplopia) - Eliminate abnormal head position - Provide single binocular vision - Symptomatic heterophorias - Abnormal head postures - Nystagmusbull In a patient with a long-standing paresis what are the

considerations when prescribing prismbull In a patient with a recent onset paresis what are the

considerations when prescribing prismbull How do you prescribe prism using Sheardrsquos criterionbull How do you prescribe prism using Calorosorsquos Residual

Vergence Demand Criterion

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Terminologya Corrective or Neutralizing Prism bull Goal ndash To stabilize normal sensory fusion bull Prism Action ndash Neutralizes the demand for controlling

fusional vergenceb Relieving Prism bull Goal ndash To stabilize sensorimotor fusion bull Action ndash Reduces the demand for controlling fusional

vergencec Overcorrective Prism bull Goal ndash To disrupt anomalous correspondence bull Action ndash Reverses the demand for controlling fusional

vergence

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Terminologyd Inverse Prism for Training or Disruptive Prism Therapy bull Goal ndash To increase fusional vergence ability bull Action ndash Increases the demand for controlling fusional

vergencee Inverse Prism for Cosmesis bull Goal ndash To enhance cosmesis of a strabismus when a patient

has poor treatment prognosis bull Action ndash Optically displaces the image of the eyes in a

direction opposite the strabismus when an observer views the patient

f Yoked Prism bull Goal ndash To stabilize bv in non-concomitancy or dampen

nystagmus bull Action ndash Directs the eyes into a specific gaze directiong Sector Regional Prism bull Goal ndash To stabilize binocular vision in one or more gaze

positions bull Action ndash Reduces the demand for controlling vergence in

more than 1 gaze

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

4 Constant Strabismus a Corrective Prisms for Resolvable Strabismus bull Avoid using prism when patient has Anomalous

Correspondence peripheral suppression amblyopia

bull Must have normal correspondence and normal peripheral sensory fusion

bull Monitor for prism adaptation Can use temporary Fresnel prisms

bull Once normal sensory fusion achieved for 3-6 months (can be less for infants)

- Titrate prism 2-4Δ at a time

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

3M Press-Ontrade Optics AVAILABLE PRISMS and ASPHERIC LENSES PRISMS

ASPERIC - PLUS ASPERIC - MINUS ASPERIC - D-SEGS

DiopterPower Power Power 10 1048661 + 5 -10 10 20 1048661 +10 -20 15 30 1048661 +15 -30 20 40 1048661 +20 -40 25 50 1048661 +25 -50 30 60 1048661 +30 -60 40 70 1048661 +35 -70 50 80 1048661 +40 -80 60 90 1048661 +50 -90 100 1048661 +60 -100 120 1048661 +70 -110 150 1048661 +80 -120 200 1048661 +100 -130 250 1048661 +120 -140 300 1048661 +140 350 1048661 +160 400 1048661

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Condition

Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Early onset strabisms

Surgical over and under-correction is a common problem

Preoperative prism adaptation enhances surgical outcome or establishes fusion nonsurgically

To obtain presurgical fusion without weight thickness and incoveniene of conventional prisms

To provide a fusion lock and stability for post-surgical residual deviations

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUS

Mild Amblyopia

Requires early intervention to avoid progression

Applied over the preferred eye as a weak patch

Small image degradation of prism serves as weak occluder

Prisms blurs visual acuity in dominant eye

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSNystagmus Can allow

patient to assume a more normal head position to find the null point of the nystagmus

Prisms with the base away from the direction gaze preference can allow the eyes to rotate into position without a large head turn

Redirects the visual gaze toward the fireld of minimal tremor

Requires placement of prisms over both lenses In absence of strabismus the power needs to be matched

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

STRABISMUSInoperable strabismus

Fragile health or patient concerns may delay or preclude surgery

Provides cosmetic improvement by shifting the apparent position of the eye in a desirable direction

For cosmetic improvement of certain tropias with an inverse prism applied before the deviating eye (egbase-in prism for esotropia)

For constant tropias where surgery is not contemplated and binocualr fusion is not possilbe

Cosmesis

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

3th 4th and 6th nerve palsies

May recover with time

Allows binocularity during recovery period May be changed as muscle function returnes

To eliminate diplopia resulting from recent-onnset strabismus (egstroke ocualr muscles paresis systemic disease)

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

DIPLOPIA Associated with several health issues Ie including mechanical restrictions neurologic disorders (nerve palsies) poststroke skew deviation postretinal detachmentscleral buckles thyroid ophthamology injuries such as blowout fractures and brain injuries

Incomitant strabismus

Deviation varies with gaze direction0

Applied over part of a lens at allow correction in specific gaze positions

For incomitant strabismus which demands different prism power in certain fields of gaze

Prisms can be easily cut and placed on spectacles for correction where needed

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Condition Relevant Issues

Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

PHORIASSymptomatic or Decompensated phorias

Fusion disruption causes eyes to deviate

Promotes fusion reduces deviation

For symptomatic phorias with different distance and near angles apply prism to upper andor lower portions of spectacle lenses

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Condition Relevant Issues Function of 3M Press-On prism

Suggested use of 3M Press-on Prisms

Other Medical Indications for Press-On prisms

Bed-ridden patients

Cannot elevate head to read or watch television

Based-down prisms on both lenses change imagersquos angle

Apply 30 prism base down to each spectacle lenses

Ankylosing spondylitis other postural deformities

Limited head movement

Prisms change imagersquos angle

Apply prism base up to spectacle lens

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

case1A 45 years- old man who had car accident

two week ago came with intractable diplopia Vision 2020(ou)Motility 40 prism diopter ET with limitation

of abduction(-4) in right eyeFundus normal

What is your management

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

case215 years old boy referred to strabismus clinic

for deviation He had occasional deviation especially after illness and complain of asthenopia

BCVAOU2020Refraction-05sph(OU)EOM10 prism diopterX(far)2o prism

diopterX (near) Fundus normal What is your planWhat is your

plan

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Other indicationFourth Nerve ParesisAccommodative EsotropiaAcquired EsotropiaIntermittent ExotropiaMultiply Operated StrabismusThyroid OphthalmopathyNystagmus

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Sixth Nerve ParalysisAcute cases of any age or origin are followed

without treatment for 3 to 4 weeksIf healing begins within a month it typically

will be progressive and completeAfter 1 month if disabling diplopia persists

and recovery is not progressing or if a child remains esotropic in all gaze positions so that binocularity is threatened then injecting the medial rectus (MR) on the affected side(s) is appropriate

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

for diabetic patients who have a generally good prognosis the value of botulinum toxin treatment lies in earlier rehabilitation

botulinum toxin to release MR contracture makes it appropriate to wait a full 6 months after the onset before transposition surgery

Injection several months after surgery has corrected several undercorrected transposition cases and may need to be repeated

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Infantile EsotropiaSimultaneous bimedial toxin injection is quite

successfulAll reports include 2 years or more of follow-

up and show high correction rates of 60 to 80 with multiple injections

Perform simultaneous bimedial injectionInject as early as age 3 monthsRepeats simultaneous bimedial injection with

recurrence of esotropia exceeding 15 PD

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Side effectPtosisInduced vertical deviationHemorrhagePupillary dilationGlobe perforation

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

orthopticsGoal is give comfortable binocular visionused to combat

suppressionamblyopiaARCenhance fusional amplitude and improve stereopsis

In successful case transform tropia to phoria but not eliminate it

Supervision and direction of treatment responsibility of ophthalmologist

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

ApplicationConvergence insufficiencyFusion trainingAntisuppression trainingARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Convergence insufficiencyMost effective treatmentConverge on an approaching object such as pencil or a

light while red filter is placed over one eyeAware of physiologic diplopia of a distant object while

fixing on a target at nearTraining fusional convergence with base out prism or

major amblyoscopeBase out prism used during reading and continue on

home with increasing power

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Fusion trainingTraining of fusion amplitude enable

symptomatic heterophoria patient more comfortable

Done by major amblyoscope or prism exercise

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

Antisuppression TrainingOrthoptic is aimed to awareness of physiologic

diplopia in heterophoria and diplopia in heterotropia

Once diplopia elicited vergence control activatedForcing suppressed area concurrently with

corresponding area of dominant eyeStimulation of retina of deviated eye by moving

visual target on major amblyoscope back and forth across suppression scotoma

Suppression cannot be effectively eliminated by orthoptic

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC

ARCTreatment is no longer practicedThe methods that were used are historical

and theoreticBased on principle that if the image of the

fixation point is moved with the amblyoscope over the retina of the deviated eye anomalous localization of the double image may suddenly be replaced by normal localization

ARC had benefit in preserving advantage of normal binocular vision so do not treat it

• Slide 1
• Non- Surgical Strabismus management
• Slide 3
• Slide 4
• Slide 5
• Slide 6
• Slide 7
• Slide 8
• What is the prescription aim
• Slide 10
• Prescribing for Children
• spectacle
• Slide 13
• Slide 14
• case1
• Glass Bifocal
• Slide 17
• Slide 18
• Slide 19
• Slide 20
• High ACA Ratio
• Slide 22
• Intermittent XT
• Slide 24
• Slide 25
• Refractive Errors
• Slide 27
• Occlusion
• Various Non-Surgical Therapies for Intermittent Exotropia
• Indications for Surgery
• The AAO PPP pediatric glass prescribing guideline
• Slide 32
• Hyperopia associated with partly of full accommodative esotropia
• Undercorrection amp overcorrection
• Slide 35
• Slide 36
• بیمار 33 ساله ای با انحراف چشم و دو بینی از 2 هفته قبل مراجعه کرده است
• Slide 38
• Slide 39
• Ophthalmic Prism
• Slide 41
• Slide 42
• Slide 43
• Slide 44
• Slide 45
• Slide 46
• Slide 47
• Slide 48
• Slide 49
• Slide 50
• Slide 51
• Slide 52
• Slide 53
• Slide 54
• Slide 55
• Slide 56
• Slide 57
• Slide 58
• Slide 59
• Slide 60
• Slide 61
• Slide 62
• Ophthalmic Prism
• Slide 64
• Ophthalmic Prism Prism For Head postures
• Chin Depression
• Slide 67
• Slide 68
• Slide 69
• Relieving Prism
• Slide 71
• Slide 72
• Slide 73
• Slide 74
• Slide 75
• Slide 76
• Symptomatic Heterophoria Prismatic correction of exophoria
• Prism for Symptomatic Heterophoria
• Slide 79
• Slide 80
• Slide 81
• Slide 82
• Slide 83
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus OBLIQUE PRISMS
• Slide 85
• Slide 86
• Slide 87
• Slide 88
• How to Prescribe a Prism for Combined Vertical and Horizontal Strabismus (OBLIQUE PRISMS)
• Slide 90
• Slide 91
• Slide 92
• Slide 93
• Slide 94
• Slide 95
• Slide 96
• Slide 97
• Slide 98
• Slide 99
• Slide 100
• Slide 101
• Slide 102
• Slide 103
• Slide 104
• Slide 105
• Slide 106
• Slide 107
• Slide 108
• Slide 109
• Slide 110
• Slide 111
• Slide 112
• case1
• case2
• Slide 115
• Slide 116
• Slide 117
• Slide 118
• Other indication
• Sixth Nerve Paralysis
• Slide 121
• Slide 122
• Infantile Esotropia
• Slide 124
• Slide 125
• Side effect
• Slide 127
• orthoptics
• Application
• Convergence insufficiency
• Fusion training
• Antisuppression Training
• ARC