orthokeratology power point presentation

WelcomeBuck & ToddOptometrists

Orthokeratology: Corneal Reshaping

Therapy Presentation

Orthokeratology• Orthokeratology is the

use of a corneal reshaping device, to mould the cornea to reduce or correct myopic (short-sighted) and mild astigmatic refractive errors of the eye.

• (Soon Hyperopia and astigmatism)

Corneal Reshaping Technology

• In some ways it is similar to the use of dental braces by an orthodontist to straighten crooked teeth.

• The main difference is that if a tooth position is corrected for some months it will usually stay in the new position.

Orthokeratology• The cornea is highly

elastic however, and always returns to its original shape. For this reason retainer lenses are worn several nights per week after the ideal corneal shape has been achieved.

Why Have Ortho-k ?

• The main purpose of Orthokeratology is to be free of both contact lenses and spectacles for all waking hours.

• Ideal for sportsmen and women, swimmers or those who work in dusty or dirty environments,

To have a lens free day.!!!

Why Have Ortho-K?

• People with allergies• Dusty Environments• Firemen• Farmers• Builders• Cold Room

Employees.

Why Have Ortho-K ?

• The freedom from any optical correction appeals to many other myopic spectacle and contact lens wearers.

• School age children benefit greatly:-No more lost contact lenses or broken frames.

Why Have Ortho-K Cont’d ?

• Contact lens wearers that have developed dry eyes, discomfort or sensitivity to their lenses.

• Surgery is not in your comfort zone.

Can Ortho-k Slow Myopia?

• In late 2004 a study published in an international journal found that Orthokeratology can slow myopia progression by an average of 50%

Myopia Control

“The etiology of myopia has excited an immense amount of speculation and controversy...and the theories which have been put forward to explain its development are as

ingenious, fanciful and contradictory as have accumulated around any subject in medicine.”

Sir Stewart Duke-Elder, 1970

Myopia Control

• Bifocal LensesRelaxing accommodation

• Rigid Contact Lenses ???• Contact Lens Corneal

Reshaping (CRT)Anterior aspheric optics

• Pharmacologic InterventionTarget specific anatomic structures of the eye

Bifocal Spectacle Studies

• Fulk et. al. IOVS

(2000)

0.25 D. Difference

• Edwards et. al. IOVS

(2002)

<0.25 D. Difference

COMET Trial Gwiazda et.al. 2003 Three Year Results

SV Spec -1.40 D. BF Spec -1.20 D. < Myopia = 0.20 D.

Do Bifocal Spectacle LensesDecrease Myopia in Children ???

More Consistent, Full Time, CorrectionAll previous studies plagued with

patient non-compliance

No.No.

Myopia has Historically Been Associated With Nearwork.

Does this premise hold true?

• STUDY:

• Journal of Paediatric Ophthalmology and Strabismus 1993.

The Influence of Study Habits on Myopia in Jewish Teenagers

Journal of Pediatric Ophthalmology and Strabismus

September / October Vol 30 . No. 5 1993

870 multicultural Jewish teenagers attending school in Jerusalem.

Females in General SchoolsFemales in Orthodox

SchoolsMales in General School

Males in Orthodox Schools

Orthodox Males• Sustained near vision

(16 hours a day)

• Frequent changes in

accommodation (due to habitual head rocking)

• Need for accurate

accommodation (when reading tiny print, 1.0 mm

height)

Myopia in Orthodox Males is worse than the general population.

Females in General SchoolsFemales in Orthodox SchoolsMales in General School

Orthodox Males

No Refractive Error

Percentage without Refractive Error.

Percentage with Gross Myopia.

Is there a link between Close Work and Myopia?

•Yes.

Does Under-correction Slow the Progression of Myopia?

• STUDY

• Chung, et al. Vision Research 2002

(2 year follow-up)

Undercorrection of Myopia Enhances , Rather than Inhibits Myopia Progression

• Chung, et al. Vision Research 2002

(2 year follow-up)• Under-corrected to 20/40 (~+0.75 D)• The undercorrected group showed INCREASED myopia and

axial length compared to the fully corrected group.

Do Rigid Contact Lens Assist in Myopia Control

Katz (2003) Am J Ophthalmology

Walline (2004)Arch of Ophthalmology

Alignment Fitting Lenses

Rigid Contact Lens and Myopia Control

Katz, Schein (2003) 2 Year Results

American Journal of OphthalmologySubjects wearing

CL Group:- 0.07 D. decrease in myopia progressionCL Group:- 0.05 mm increase in axial length

A Randomized Trial of the Effects of Rigid Contact Lenses on

Myopia Progression

The Study

Axial Growth Results

Change in Axial Length

RGP = 0.81 mm SCL = 0.76 mm Difference = 0.05 mm

Change in Axial Eye GrowthTwo Year Data

0.840.79

0.6 0.59

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Katz Study Walline Study

RGPGroup

Controls RGP Group

Controls

N = 97 N = 184 N = 59 N = 57

What Can Be Said ???Over a three year period:• The alignment fitting RGP lens group

increased in myopia -1.56 D. the SCL group -2.19 D.

• This difference in myopia was related to change in the corneal curvature induced by the two different modalities.

• There were no differences in the axial growth of the eyes between the two groups.

• GP lenses DO NOT control myopia progression.

The Longitudinal Orthokeratology Research In Children (LORIC) study in

Hong Kong

A pilot study on refractive changes and myopic control in 35 children 7-12

Pauline Cho, PhD, Associate ProfessorSin Wan Cheung, MPhil, Research Associate

Marion Edwards, PhD

Department of Optometry & Radiography

The Hong Kong Polytechnic University

Department of Optometry & Radiography

The Hong Kong Polytechnic University

Vitreous Chamber Elongation After 24 Months

0.03

0.21

0.12

0.31

0.11

0.42

0.23

0.48

0

0.1

0.2

0.3

0.4

0.5

6 Months 12 Months 18 Months 24 Months

Ortho-K Control

Change in Axial Eye GrowthTwo Year Data

0.6 0.590.54

0.29

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

Walline Study Cho Study

RGPGroup

SCLGroup

ControlGroup

CornealRe-

ShapingGroup

Jeffrey J. Walline, OD PhD AOCLE Conference Montreal Canada, June 2006

Crayon Study

Inclusion Criteria• Ages 9 to 12 years• Sphere -0.75 D to -4.00 D• Cylinder less than -1.00 D• 20/20 OU• No previous RGP wear

Contact Lenses• Orthokeratology / Paragon CRT• CIBA Vision Focus 2 Week (SCL)

Walline One Year ResultsVitreous Chamber Depth

0.27

0.14

0

0.05

0.1

0.15

0.2

0.25

0.3

SCL Control CRT

Conclusions• 3 out of 4 children can wear Paragon CRT lens

for corneal reshaping.

• Confirms study by Cho, et al. that: Corneal reshaping contact lenses

slow axial growth of the eye.

Myopia Control Trough Optical Intervention

Does the Fovea Control the Axial Growth of the Eye ???

Earl Smith et.al. University of Houston

What Does This Mean ???

These data demonstrate that the fovea DOES NOT play the dominate role in refractive development.

Instead peripheral retinal image plays the MAJOR role in determining overall eye growth.

-3.00 D. Change

Shape Factor +0.41

Shape Factor -0.43

The “Image Shell” Post OKNegative Curvature of Field

The post OK cornea generates a negative curvature of field. Central rays of light are focused on the fovea. Peripheral rays of light are focused more anteriorly (in front) of the retina.

Pharmacological Intervention Medications that target specific anatomic

structures of the eye.

1. Retinal neurotransmitters

linked to eye growth.

2. Scleral remodeling enzymes and growth factors.

3. Intraocular pressure

Atropine Therapy• Long history for myopia control dating back to

the late 1960’s.

• Is a non-selective anti-muscarinic drug.

• Underlying assumption;– Excessive accommodation implicated.

Chau ATOM Study ARVO 2003400 subjects 331 at 2 years

Ages 6 – 12 with Myopia -1.00 to -6.00 D. Atropine 1% once a day for two years

No Growth

Control

Side Effects of Atropine 1%Cycloplegia and photophobiaDecreased performance at nearUltraviolet absorptionPossible macular damagePapillary & Follicular conjunctivitis

Ocular and Systemic toxicityRespiratory infectionFever

Pirenzepine Ophthalmic 2% Gel

• Novartis Ophthalims, Basel Switzerland

• Valley Forge Pharmaceuticals, Irvine CA

• Currently the product has been discontinued from clinical trials.

Pirenzepine Gel

Siatkowski, et al. IOVS (2002)174 Subjects Ages 8 - 12

Pirenzepine 2% BIDPlacebo BID

Refractive Change PIR BID -0.26 D Placebo -0.53 D

Axial Length Change PIR BID 0.21 mm Placebo 0.33 mm

Change0.27 D 0.12 mm

Pirenzepine

Siatkowski, et al. IOVS (2002)– 0% of placebo subjects dropped due to adverse

events– 11% of PIR subjects dropped due to adverse

events• Gel residue on lids

• Blurred vision at near

• Asymptomatic conjunctival reactions

Pirenzepine Gel Tan et.al. ARVO 2003

353 Subjects Ages 6 - 12 Pirenzepine 2% BID

Placebo BID

Refractive Change PIR BID -0.47 D Placebo -0.84 D

Axial Length Change PIR BID 0.21 mm Placebo 0.33 mm

Change0.37 D 0.12 mm

Pirenzepine Complications Tan et.al. ARVO 2003

• Abnormalities of accommodation

• Papillae and follicles

• Systemic complications– Cough– Respiratory infection– Fever– Rhinitis– Abdominal pain

Myopia Control

Bifocal LensesRelaxing accommodation Rigid Contact Lenses? Improving retinal imageryMyopia under-correction-0.75 DOptical InterventionsCurvature of field modificationPharmacologic InterventionOral delivery, target specific anatomic structures i.e. sclera

Earl Smith 2005 Eye growth may possibly be retarded, or

halted through:

“A precise and pre-determined optical system at the corneal plane that will manipulate the peripheral optics of the eye.”

SummaryIdeally the Myopia Controlling device should maintain axial alignment “centered” with the eye regardless of the position of gaze i.e.

The ideal system would be one that that could be easily changed as the ocular power and peripheral aberration profiles change.

Contact lenses Orthokeratology Refractive surgery Intraocular lens Corneal implants

Night Therapy!!

• For most people it is possible to go straight to night therapy. This gives a fast and easy way of arriving at myopia correction.

Lenses are inserted before going to sleep and removed in the morning.

Therapy Progression

• As the therapy progresses and the cornea is moulded, the lenses give good unaided vision for longer periods of time. Gradually the lens wearing time may be decreased to a level, which gives the desired reduction in myopia.

Teenagers.

• Possibly the ideal situation for using Ortho-K is for the teenager just becoming Myopic.

• Not only does it have all the advantages already discussed, but the procedure appears to stabilise or retard the progression of the Myopia.

Every Night?

• Lenses will still need to be worn at night, but the frequency of wearing time varies between individuals.

Advantages Over Surgery.

• Ortho-K costs less and is a reversible procedure.

• It is also more appropriate for people whose eyes are still changing

IS EVERYONE SUITABLE FOR Ortho-K?

The procedure works best up to -4.00 dioptres of

Myopia and -1.0 dioptres of Astigmatism.

New designs are expected to come available for

prescriptions up to -6.00D and for hyperopes up to

+3.00D

IS EVERYONE SUITABLE FOR Ortho-K?

• The procedure also does not work as effectively on very steep or very flat corneas.

• In addition there are several unknown factors for each individual; The complexity of the corneal shape and the rigidity of the cornea itself.

Contra-indications:

• Extreme dry eye (unable to tolerate regular contact lenses)

• Patients that have had laser or LASIK surgery

• Any active or recurrent ocular surface disease

• Keratoconus

Lost Lenses: Ceasing Wear

• In the event of a lost lens the cornea will tend to return to its original shape.

• A spare pair of lenses is provided in the schedule, and a new lens takes 3 working days.

Lost City of Petra.

Aftercare.

• As with any contact lens wear it is vital to ensure the health and integrity of the cornea at all stages.

Over the first year many visits are involved.

Aftercare Continued.

• After the initial therapy an examination twice a year is considered essential to ensure ongoing safety of the eyes and good vision

History

• Orthokeratology, (also referred to as ortho-k) was first introduced to contact lens practitioners by the famous optometrist George Jessen in 1962.

History.

• The initial flurry into Orthokeratology was hindered by poor technology and understanding of the criteria needed to successfully and predictably correct myopia.

New Technology.

• Orthokeratology re-emerged as a viable alternative from 1989 due to the development of new technologies

Accelerated Optimal Ortho-K

• Accurate Corneal Topographers.

• Computerised image analysis.

• Subtractive image maps to evaluate changes.

A Current Affair.

OOK.

• High tech laboratory equipment.

• High oxygen transmissible materials.

Improved Reverse Geometry

• Changes to contact lens designs achieved with high tech precision laser guided lathes

WHAT ARE THE DISADVANTAGES OF

ORTHO-K?• You must be prepared to

allow for 4-10 visits over 3-6 months.

• Retainer lens wear is essential or the cornea will revert to its original shape.

• The degree of success is high but cannot always be guaranteed.

Disadvantages Cont’d..

• The rate of improvement varies from one person to the next.You must be prepared to follow instructions implicitly for the best results.

• Reaching the optimal vision result can take up to 3 months.

• Vision will fluctuate over the first 10 to 14 days.

Does ORTHO-K Have Any Advantages Over EXCIMER

Laser Surgery?• Yes!

• The procedure is REVERSIBLE (Excimer is not!).

• It does not involve post-operative pain.

• It does not leave the hazy vision often experienced by patients following laser surgery.

• There is no loss of Bowman's membrane (the tough protective layer just under the Corneal surface).

Does ORTHO-K Have Any Advantages Over EXCIMER

Laser Surgery?• Yes!!

• Changes in prescription over time can be dealt with (unlike Excimer).

• Ortho-K is significantly cheaper.

• No age limit. (not recommended under age 8 years.)

• Both eyes are done together (rather than several weeks or months apart).

Fees and Charges.• The technique involves the

provision of specialist Orthokeratology contact lenses and a number of visits to your practitioner.

• Each practitioner sets their own fees which may vary dependant on the Rx being treated..

Fees and Charges:-Rebates.

• Like laser surgery there is no rebate available from health funds on this technique, however, some funds do cover part of the cost of the contact lenses.

Cost.

• The procedure is time consuming and can involve several Lens changes.

• However, once complete, the on-going costs are no greater and often less than conventional Contact Lens wear.

http://www.optics-shop.com/

Cost Analysis.

• Ortho-K.• 2 weekly disposable

contact lenses.• 30 day continuous wear

contact lenses.• Monthly disposables.• Daily disposable lenses.

Year 1.

$0.00

$200.00$400.00$600.00$800.00

$1,000.00$1,200.00

$1,400.00

Ortho-K 2 WeeklyDisposable

30 day C/W MonthlyDisposable

DailyDisposable

Lens Type

Care ProductsLensesFees

Year 2.

$0.00

$200.00

$400.00

$600.00

$800.00

$1,000.00

$1,200.00



DailyDisposable

Lens Type

Fees Lenses Care Products

Year 3.

$0.00

$200.00

$400.00

$600.00

$800.00

$1,000.00

$1,200.00



DailyDisposable

Lens Type


Year 4.

$0.00

$200.00

$400.00

$600.00

$800.00

$1,000.00

$1,200.00



DailyDisposable

Lens Type


Year 5.

$0.00

$200.00

$400.00

$600.00

$800.00

$1,000.00

$1,200.00



DailyDisposable

Lens Type


Total 5 Year Cost Analysis.

$0.00

$1,000.00

$2,000.00

$3,000.00

$4,000.00

$5,000.00

$6,000.00



DailyDisposable

Lens Type


5 Year Cost with Glasses.

$0.00

$1,000.00

$2,000.00

$3,000.00

$4,000.00

$5,000.00

$6,000.00

$7,000.00



DailyDisposable

Fees Lenses

Care Products Glasses

Rx Sunglasses

Adapting to Refractive Change.

• Another benefit of OOK is that its effects can be adjusted or modified .

• As a patient’s myopia increases, we design a new lens to move more epithelial cells, creating more focusing power.

Presbyopia:-Aging Eye.

• When a patient reaches their 40’s, the ability to focus on near objects is reduced which is called presbyopia.

• OOK can be adjusted on one or both of the eyes to provide good distance vision but at the same time, improve a patients’ ability to focus on nearby objects as well (called monovision).

Orthokeratology Is a Safe and Effective Vision Correction

Procedure That Requires No Surgery.

If You Are Unsatisfied With the Results It Is a Completely

Reversible Procedure.

All You Have to Do Is Take Out the Retainer Lenses and No

Longer Wear Them.

Summary.

Be Free to See Exceptionally, Without Any Aid!!!

• Each night before going to bed, you will insert you OOK retainer.

• It has been designed so that you can see to read before sleeping or provide you with adequate vision should you wake up in the middle of the night for any reason.

•

.


–As soon as you wake in the morning, you will employ the proper removal, handling, and cleaning techniques and place your retainers in their case.

•And the best part....You see exceptionally, without any aid!!!

Totally Wild.


Accelerated Optimum Orthokeratology

orthokeratology power point presentation

Health & Medicine

lost contact lenses

contact lens wearers

corneal reshaping technology

corneal reshaping device

ideal corneal shape

etiology of myopia

reason retainer lenses

slow myopia progression