Approach to a Patient with GlaucomaBy Dr Lakshmi K SModerator: Dr Rajani Kadri

Glaucoma is defined as a group of disorders characterized by a progressive optic neuropathy resulting in a characteristic appearance of the optic disc and a specific pattern of irreversible visual field defects that are associated frequently but not invariably with raised intraocular pressure (IOP).

Proforma for examination PRILIMNARY DATA• Name:• Age: • Sex:• Occupation:• Address: HISTORY TAKING• Chief complaints:• History of presenting

complaints:• Past history:• Personal history:• Family History:

EXAMINATION• General Physical

Examination:• Systemic Examination: OCULAR EXAMINTION• VISUAL ACUITY ANTERIOR SEGMENT

EXAMINATION:• EYE LIDS• CONJUNCTIVA• CORNEA• SCLERA• ANTERIOR CHAMBER

• IRIS• PUPIL• LENS• FUNDUS• IOP• ANGLE OF ANTERIOR

CHAMBER VISUAL FIELD TESTING NEWER

TECHNOLOGIES

PRILIMNARY DATA

Name: identification and familiarisation Age: POAG=40-60 yrs, NTG>60 yrs, ACG with

pupillary block- 60 yrs, ACG without pupillary block-40-50 yrs.

Sex: OHT- males, OHT→POAG- males, NTG- females, PACG- females

Occupation: Lower levels of occupation- increased visual morbidity

Address: POAG- European and African ethnicity, NTG- Japanese, PACG-Indians

Chief Complaints

Symptoms depend upon:1. Onset of disease—acute and chronic2. Age of patient- higher the age, greater is the risk of visual loss3. Rise of IOP• How fast- acute rise- acute symptoms, chronic raise- may be

asymptomatic• How much- PACG and Pseudoexfoliative Glaucoma- VF change

correlation with IOP high, POAG- VF change correlation is less• Duration of raised tension- longer the duration, more is the

glaucomatous damage and larger is the field defect4. Associated ocular diseases: cataract, uveitis, trauma, retinopathy

and vascularisation

1. No symptoms2. Visual(a) Diminished distant vision• Sudden—acute glaucoma, both primary orsecondary• Gradual—all chronic glaucomas with moderaterise of tension(b) Diminished near vision: Early onset of presbyopia and frequent

change of presbyopic glasses is seen in chronic simple glaucoma(c) Loss of field—Unless there is extensive loss of field, it may go

unnoticed; however patient with good central vision and constricted peripheral field may complain of tubular vision

(d)Photophobia is seen in congenital glaucoma due to rupture of Descemet’s membrane

(e)Colored haloes are seen in sudden, moderate to high, rise of IOP. Common causes are prodromal stage of primary angle closure glaucoma, acute secondary glaucoma and epidemic dropsy glaucoma

3 . Lacrimation is prominent feature of congenital glaucoma and acute glaucomas

4. Pain is seen in acute rise of tension, both primary and secondary. In acute congestive glaucoma, it is a very prominent feature, a throbbing ocular pain with peri orbital tenderness associated with nausea/vomiting. Unexplained pain in uveitis and corneal ulcer may raise the suspicion of glaucoma.

5. Redness of eye(a) Circumciliary congestion is seen in acute congestive glaucoma,

chronic congestive glaucoma and some secondary glaucomas(b) Episcleral congestion is seen in absolute glaucoma and raised

episcleral pressure

History of Presenting illness

Previous attack of acute glaucoma Treatment taken for any glaucoma Trauma, surgery, uveitis, retinopathy Diabetes, hypertension, dysthyroid

condition, epidemic dropsy Local or systematic use of steroid Coloured haloes

Past history: diabetes, hypertension, asthma, seizures

NTG associated systemic diseases-migraine headache, raynauds disease, MI, nocturnal hypotension, autoimmune diseases, shock syndromes, anaemias, DM, sleep aopnea syndrome

Family history: glaucoma, diabetes, Hypertension • Risk is increased by x2 if parent has POAG• Risk is increased x4 if sibling has POAG

Personal history: smoking, alcohol

General examination Systemic diseases associated with Glaucoma1. autoimmune diseases-JRA, Ankylosing spondylitis2. Infections- congenital Rubella, Leprosy, Syphillis3. Vascular and hematologic disorders(NVG)- sickle cell anemia,

vessel occlusions4. Neoplasias- metastatic CA of breast an d lung5. when the glaucoma and systemic disorder are parts of a

syndrome- Phakomatoses, Axenfeld Reiger Syndrome, Marfans dyndrome, Weil Marchesaani syndrome

6. when the glaucoma and systemic disease are frequently seen in the same patient but there is noestablished cause-and-effect relationship- systemic hypertension, hypothyroidism, migraine headaches, nocturnal hypotension, sleep apnea, and silent myocardial infarction

OCULAR EXAMINATION Visual acuity: (a) Without glasses—will give the extent of visual loss(b) With pinhole—will indicate the limit to which vision can be salvaged

with treatment(c) With spectacle—will show the type of error of refraction, the patient

is suffering from. Myopes are more often associated with POAG while PNAG is commonly seen in hypermetropia. Many a times, patient may not be aware of diminished vision especially if it is uniocular

In some patients, vision deteriorates with treatment of glaucoma: Miotics will(a) Reduce vision in cases associated with central nuclear cataract,central corneal opacity and macular lesion(b) Cause diminished night vision(c) Reduce field of vision(d) Produce difficulty in near vision Carbonic anhydrase inhibitors may produce transient myopia Anti-glaucoma surgery may produce:• Troublesome astigmatism• Persistent hypotony

Coloured haloes DDs: acute mucopurulent conjunctivitis, ACG, Incipient cataract Fincham’s test is done using the staenopic slit to differentiate the

colored haloes caused by cataract (lenticular) from that caused by glaucoma (corneal). Staenopic slit is moved across patient’s eye while the patient looks at a bright point source of light which gives rise to halo. The halo caused by cataract breaks into a fan the blades of which seem to move whereas the halo caused by glaucoma remains unchanged or just becomes a little faint. This is caused by peculiar disposition of the lens fibers which cause diffraction of light parallel to them.

Anterior Segment Examination Eye Lids: congested and edematous in

an acute attack of angle closure glaucoma

Conjunctiva(i) Circumciliary congestion is seen in

acutecongestive glaucoma, chronic congestiveglaucoma and absolute glaucoma(ii) Episcleral congestion is seen in raised

episcleral pressure. Typical corkscrewing of vessels seen. d/d CCF

Cornea (i) Rupture in Descemet’s membrane and Haab’s

striations are seen in congenital glaucoma(ii) Corneal oedema is seen in acute rise of tension(iii) Krukenberg spindle is sometimes seen in

Pigment dispersion glaucoma(iv) KP may be present following acute rise of

tension, or uveitis(v) Band keratopathy is seen in long-standing

glaucoma(vi) Diminished corneal sensation is seen with acute

rise of tension(vii) Bullous keratopathy is seen in absolute

glaucoma(viii) Vascularisation may be present in the absolute

stage

Sclera(i) Thinning and stretching of sclera is very common in congenital

glaucoma(ii) Scleral ectasia is seen in congenital glaucoma and sometimes in

absolute glaucomaAnterior chamber depth(i) Normal—in chronic simple glaucoma and some secondary

glaucomas(ii) Shallow—in NAG, lens-induced glaucoma and malignant glaucoma(iii) Deep—buphthalmos, aphakic glaucoma, trauma and pseudo-

phakic glaucoma

Measurement of anterior chamber depth(a) By oblique illumination(b) Comparing corneal thickness to anterior

chamber depth - Van Herick’s grading(c) Shadow of temporal iris(d) Pachymetry(e) A Scan(f) B Scan

ANGLE DEPTH

Grade 4 angle AC depth =corneal thickness

Grade 3 angle AC depth= ¼ to ½ corneal thickness

Grade 2 AC depth= ¼ corneal thickness

Grade 1 angle AC depth= less than ¼ corneal thickness

Slit angle AC depth=slit like (extremely shallow)

Closed angle Absent peripheral anterior chamber

UBM

Helps in differentiating open and closed angle glaucoma

Diagnosis of• Plateau iris syndrome• Angle recession glaucoma• Lens induced glaucoma• Cysts and tumors of angles causing

glaucoma

Iris(i) Loss of pattern is due to oedema or

iris; it is commonly seen in acute congestive attack of glaucoma, both primary and secondary

(ii) Atrophic patches are seen following iritis glaucomatosa, chronic congestive glaucoma and absolute glaucoma- segmental iris atrophy in ACG and herpes simplex uveitis and diffuse in OAG, Senility, Chronic uveitis.

(iii) Posterior synechiae—sudden high rise of intraocular tension, anterior uveitis, iritis and glaucomatosa result in posterior synechiae

(iv) Peripheral anterior synechiae are seen following unrelieved tension in acute congestive glaucoma, chronic uveitis and neo-vascular glaucoma

(v) Neovascularisation—thrombotic glaucoma

(vi) Coloboma—surgical, laser and trauma

(vii) Holes—(positive trans-illumination) are seen in essential iris atrophy, mesodermal dys-genesis of anterior chamber, glaucomatocyclitic uveitis, heterochromic uveitis, pigment dispersion syndrome and herpes zoster

(viii) Flakes are seen in pseudo-exfoliation syndrome

Pupil A large, sluggish pupil with fairly good vision, without a history of

use of mydriatic, in a person past 40 years should raise the possibility of increased intraocular tension unless proved otherwise

An afferent pupillary defect in glaucoma denotes unilateral advanced glaucomatous change in the optic disc

A Mid-dilated, sluggish, vertically oval pupil in a congested eye means acute narrow-angle glaucoma due to the nerve endings being concentrated on superior and inferior poles and vessel bundles being concentrated on the horizontal poles

A constricted pupil should invite enquiry about the instillation of a miotic, its strength and frequency. All small pupils should be examined to exclude iritis

Distorted pupil is seen in trauma, uveitis, chronic congestive glaucoma and absolute glaucoma

Lens Cataract: Mature / Hypermature

(Lens Induced Glaucoma) Pseudoexfoliation material Glaucomflecken (with patchy

iris atrophy and mid dilated non reacting pupil forms the vogt’s triad of ACG)

Pigments on lens Posterior synechae Complicated cataract- chronic

glaucoma

Fundus

Media

clear

Glaucoma

evaluation

Hazy

cataract

Fundus Changes in glaucoma Glaucomatous damage

results in characteristic signs involving

(a) the optic nerve head, (b) the peripapillary area (c) the retinal nerve fibre

layer

Optic Nerve Head Cup Disc Ratio: Normal is 0.3-0.5 The appearance and pattern of disc damage may

correlate with subtypes of glaucoma and provide clues as to the pathogenic mechanisms involved. Four ‘pure’ glaucomatous disc appearances have been described, although the majority of discs are unclassifiable

1. Focal ischaemic discs are characterized by focal superior and/or inferior polar notching

2. Myopic disc with glaucoma refers to a tilted (obliquely inserted), shallow disc with a temporal crescent of parapapillary atrophy, together with features glaucomatous damage

3. Senile sclerotic discs are characterized by a shallow, saucerized cup and a gently sloping NRR, variable peripapillary atrophy and peripheral visual field loss

4. Concentrically enlarging discs (verified by serial monitoring) are characterized by uniform NRR thinning

Non-specific signs of glaucomatous damage

Baring of circumlinear blood vessels is a sign of early thinning of the NRR. It is characterized by a space between a superficial blood vessel that runs from the superior or inferior aspects of the disc towards the macula, and the disc margin

‘Overpass cupping’, in which there is loss of NRR underlying vessels, leaving space between the bridging vessels and the remaining nerve tissue, is similar.

Bayoneting is characterized by double angulation of a blood vessel With NRR loss, a vessel entering the disk from the retina may angle sharply backwards into the disk and then turn towards its original direction to run across the lamina cribrosa.

Size of the disc: 1.5-1.7mm is normal size. Vertical diameter is measured on slit lamp biomicroscopy. Larger discs are more amenable to glaucoatous damage.

Collaterals between two veins at the disc Loss of nasal NRR is a sign of moderately advanced damage;

a space may develop between the NRR and the central retinal vasculature. Does not follow ISNT rule. Highly sensitive but not specific.

Lamina dot sign occurs in advancing glaucoma. The gray dot-like fenestrations in the lamina cribrosa become exposed as the NRR recedes

Disc haemorrhages (Drance Haemorrhagea) often extend from the NRR onto the retina, most commonly inferotemporally

‘Sharpened edge’ or ‘sharpened rim’ is a sign of advancing damage. As NRR is lost adjacent to the edge of the disc, the disc margin contour assumes a sharper angle backwards

(A) Inferior baring of circumlinear blood vessels; (B) inferior bayoneting; (C) collaterals; (D) loss of nasal neuroretinal rim; (E) lamellar dots; (F) disc haemorrhage

Disc Damage Likelyhood Scale

The disc damage likelihood scale (DDLS) was devised by Spaeth et al in 2002 to incorporate the effect of disc size and focal rim width into a clinical grading scale

 Disc size can be measured using a fundus lens at the slit-lamp

A 66D gives the exact measure from the graticule. Correction factors for the other lenses are Volk 60D-0.8878D-1.2 90D-1.33

DDLS advocates measurement of the width of the thinnest part of the rim.

This forces the examiner to evaluate the rim throughout its entire circumference in order to identify the area of greatest thinning. The measurement is expressed in rim:disc. Where there is no rim present at the thinnest point the value is 0. The circumferential extent of rim absence is then measured in degrees.

Peripapillary changes Peripapillary atrophy surrounding

the optic nerve head may be of significance in glaucoma and may be a sign of early damage in patients with ocular hypertension.

Alpha (outer) zone is characterized by superficial retinal pigment epithelial changes. It tends to be larger and possibly more common in glaucomatous eyes.

Beta (inner) zone is characterized by chorioretinal atrophy. It is larger and more common in glaucoma.

Retinal nerve fibre layer In glaucoma subtle retinal nerve

fibre layer (RNFL) defects precede the development of detectable optic disc and visual field changes; their onset often follows disk haemorrhages. Two patterns occur:

(a) localized wedge-shaped defects (b) diffuse defects that are larger

and have indistinct bordersRed-free (green) light increases the contrast between normal retina and defects on slit-lamp biomicroscopy and typically makes identification easier

Early signs of glaucomatous damage

Retinal nerve fibre layer Nerve fiber layer dropout Optic nerve head

1. Focal notching of neuroretinal rim - Thining of infero-temporal Rim (ISNT rule is not preserved)

2. Vertical elongation of cup3. Asymmetry of cupping between 2 eyes

Non specific signs of glaucomatous damage1. Baring of circumlinear blood vessels2. Splinter haemorrhages

Late signs of glaucomatous damage

Optic nerve head1. Generalized enlargement of cup2. Vertical elongation of cup3. Asymmetry of cupping between 2 eyes

Peripapillary changes Non specific signs of glaucomatous damage

1. Exposure of lamina cribrosa2. Bayoneting (double angulation of blood vessel)

Intra Ocular Pressure

IOP is the oncotic pressure exerted by the contents of the eyeball on the coats of the eyeball to maintain the integrity of the eye ball. The normal intraocular pressure is between 10 mm Hg and 21 mm Hg.

Goldman’s applanation tonometer is the gold standard instrument for IOP measurement

(a) More than 21 mm Established glaucoma Ocular hypertension(b) Less than 21 mm Normal Glaucoma suspect Glaucoma under treatment Normal tension glaucoma

Central Corneal Thickness The CCT is undoubtedly of value in management of both

glaucoma and glaucoma suspects, especially occur hypertension.

Thicker corneas produce falsely higher reading while thinner corneas produce falsely lower readings. However, corneal thickening due to edema causes a falsely lower reading.

A meta-analysis of many different populations deduced 2.5 mm Hg for every 50 µ increase in CCT

An average error is 0.5-0.7 mm Hg per 10 microns of deviation from the mean of 520 microns.

Patients with less than 555 U had 3 times greater risk of POAG

CCT importance to predict glaucoma risk (OHTS)

Conditions which influence IOPi. Diurnal variationii. Postural variationiii. Exertional influencesiv. Lid and eye movementv. Intraocular conditionsvi. Systemic conditionsvii. Environmental conditionsviii. General anesthesiaix. Food and drugs

In an eye suspected to have glaucoma, if any of the following is present then the eye should be subjected to fundus, field and gonioscopy examination.

1. If there is difference in IOP more than 7 mm between the two eyes

2. Diurnal variation—positive3. Provocative test—positive

There are four types of diurnal variation curves.They are:i. Falling type: maximal at 6–8 am followed by a continuous declineii. Rising type: maximal at 4–6 pmiii. Double variation type: with 2 peaks 9–11 am and 6 pmiv. Flat type of curve. The most common pattern is that the IOP is maximum in the

morning and decreases as day progresses and becomes minimum in the evening. It once again starts to rise as the night progresses. The variation is about 3 to 6 mm Hg in normal individuals. The variation is about 10 mm Hg or more in a glaucomatous eye.

It is due to cyclic fluctuation of blood levels of adrenocortical steroids. Maximum IOP is reached 3 to 4 hours after the peak of plasma cortisol. The night time elevated IOP is due to the supine position along with the fluctuating cortisol levels.

The various provocative tests include:i. Mydriatic testii. Dark room testiii. Prone testiv. Prone dark room testv. Phenylephrine-pilocarpine testvi. Triple test.

Examination of Angle ofAnterior ChamberAngle of anterior chamber is formed by the anterior and posterior

borders of anterior chamberThrough the angle, AC communicates with extracellular spaces of iris,

ciliary body and trabecular meshwork.Volume of AC= 220micro literAC depth= 3.15mm (2.6-4.4)AC diameter=11.3-12.4mm

GONIOSCOPYBiomicroscopic examination of the anterior

chamber

Works on the principle of prevention of total internal reflection of rays reflected from far peripheral iris, angle recess, and trabecular meshwork, by using a contact lens to eliminate the air cornea interface.

Total internal reflection occurs because angle of

incidence of rays of from the angle structures is

greater than the critical angle of cornea-air interface

(46 degrees)

Gonioscopic contact lenses have refractive index

similar to cornea, hence eliminate the optical effect

of the front corneal surface.

Ziess 4 mirror contact lens is most commonly used

goniolens for gonioscopy

A- structures normally seen on gonioscopy in an open angleB-CBB is light grey and TM is heavily pigmented. The thinner pigmented line above the meshwork is the Schwalbe's lineC-iris processesD- reflux of blood in schlemm’s canal is helpful in identifying the pigmented TM

SHAFFER GRADING

GRADE

ANGLE WIDTH

CONFIGURATION

CHANCE OF CLOSURE

STRUCTURES VISIBLE ON GONIOSCOPY

IV 30-40 WIDE OPEN NIL SCHWALBE’S LINE TO CILIARY BODY

III 20-30 OPEN NIL SCHWALBE’S LINE TO SCLERAL SPUR

II 20 MODERATELY NARROW

POSSIBLE

SCHWALBE’S LINE TO TRABECULAR MESHWORK

I 10 VERY NARROW

HIGH SCHWALBE’S LINE ONLY

0 0 CLOSED CLOSED

NONE

Tests for visual fields

Kinetic perimetry: manual confrontation method, goldmann’s perimeter, listers perimetry

Static perimetry: capimetry (tangent screen testing), Humphry’s perimeter

Confrontation method

First test the binocular visual field and then test each eye separately. A defect is detected by the absence of a patient response to the showing of a target, when the target is visible to you.

Testing to confrontation with both eyes open

Testing each eye to confrontation

Humphry’s Visual fields in glaucoma Glaucomatous visual field loss commonly occours in the

arcuate area in the sup and inf hemifields These areas arch around the fovea, starting from optic

disc and extending nasally to end at the horizontal raphe. A relative decrease in retinal sensitivity (relative

scotoma) in this rea is usually the first evidance of glaucoma. These scotomas tend to occur nasally and there is significant asymmetry bet sup and inf visual fields.

Localised field defects- hallmark of glaucoma but are frequently associated with overall reduction in sensitivity.

A pure generalised reduction in sensitivity- more likely to be due to media opacities.

Characteristics of glaucomatous defects Asymmetrical across the horizontal midline. Located in the mid-periphery (5-25 degrees from

fixation) Reproducible Not attributable to other pathology. Localised Correlating with the appearance of the optic disc

and the neighbouring areas.

Diagnosis of glaucoma Anderson’s criteria is commonly used to define abnormality

in visual fields. As per this criteria,presence of a cluster of three or more

nonedge points on the pattern deviation probability plot deviating at p<5% with

1. One of these points deviating at p< 1%;2. Pattern standard deviation(PSD) having a value (p<5%)3. Glaucoma hemifield test (GHT) outside normal limitsTwo out of these three should be present for diagnosis of

glaucoma.

Visual function in glaucoma Testing of visual field is the primary method of assessing

visual function in glaucoma patients and glaucoma suspects. Because central visual function is lost late in glaucoma,

central visual acuity is a poor test of visual function in glaucoma.

Visual field testing in used in 3 distinct ways in glaucoma evaluation and management:

1. Diagnosis 2. Assessment of severity3. Determination of progression.

Specific glaucomatous visual field defects a nasal step defect obeying the horizontal meridian a temporal wedge defect the classic arcuate defect, which is a comma-shaped extension of the blind

spot a paracentral defect 10–20° from the blind spot an arcuate defect with peripheral breakthrough generalised constriction (tunnel vision) temporal-sparing severe visual field loss total loss of field.

Progression of glaucoma

Compare to selected baseline Discard learning fields from baseline. Recognise false progression. Learning curve Long term fluctuations Artefacts Patient factors Pupil size

Glaucoma Progression Analysis

GPA™ is now in clinical use Change is based on the pattern deviation plot Compatible with both SITA and full threshold

New technologies and the future Other technologies are available and being developed in

the hope that formal visual field testing will become easier, more reliable, more affordable, and more widespread – using equipment that can detect glaucoma earlier than standard perimetry. These emerging technologies include:

short-wavelength (blue–yellow) automated perimetry (SWAP)

frequency doubling technology (FDT) perimetry motion displacement perimetry (MDP

Optic nerve imaging technologiesAlthough other technologies exist for the evaluation of the optic nerve and nerve fiber, the following are the major technologies with the greatest installed user base in 2015. Disc Photography- baseline for progression

assessment Confocal Scanning Laser Ophthalmoscopy Scanning Laser Polarimetry Optical Coherence Tomography

QUANTITATIVE IMAGING                                                         Principles                                          Clinical Parameters Measured

HRT                         Confocal Scanning Laser                      Optic Disc Tomography                                Ophthalmoscopy

GDx                         Scanning Laser                                    Retinal Nerve Fiber Layer Thickness                                Polarimetry/Birefringence

OCT                         Interferometry                                       Retinal Nerve Fiber Layer Thickness

IOP

High

Unilateral

Rule out secondary glaucomas

Uveitic

Steroid induced

Lens induced

Neovascular

Bilateral

Glaucoma suspect glaucoma

Normal

Disc changes resembling glaucoma

NTG

Old female>60 yrs, associated with risk factors like hypotension

and migraine, specific changes

in disc and visual fields.

Other causes-

congenital deep cup,

myopic disc-large disc with large cup, optic colobomas

VF changes resembling glaucomatous defects

NTG

Other causes of VF changes- tilted disc,

myelinated nerves, ONH, peripheral retinal

degenerations, extensive PRP

Glaucoma/glaucoma suspect

Accurate IOP measurement- tonometer used, central corneal

thickness, diurnal variation

Disc evauation

Early change

Difficulties like large disc and

small disc and NRR

evaluation.

Late changes

Fundus photography

No changes

Visual field evaluation

Glaucomatous Non glaucomatou

s

Undetected POAG- detected on SWAP, frequency doubling

perimetry, motion detection perimetry.

Angle assessment

Open

Closed

NTG suspicion Diagnosis of exclusion Specific characteristics- history, fundus, visual fields Investigations for systemic conditions associated with NTG• 24 hr BP monitoring• 24 hr ECG monitoring• Blood tests- CBC, Lipid profile, CRP, blood sugars,

autoimmune markers, thyroid status• Polysomnography and other sleep studies• Ocular blood flow and carotid doppler

Conclusion

Systematic approach helps in the accurate and timely diagnosis of glaucoma

References Clinical ophthalmology-Kanski Text book of OphthalmologyYanoff Clinical examination- mukherjee FAQs in Ophtahlmology- Aravind Textbook of glaucoma- Shields Optic Nerve and Retinal Nerve Fiber Imaging- Aaron M

Miller Visual field testing for glaucoma – a practical guide-

David C Broadway

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