Primary Angle Closure Glaucoma For Ugs

Primary Angle Closure Glaucoma

Introduction • ACG as a cause of world blindness is probably 3 times more likely than OAG especially in Asia.

Open angle

Closed angle

What is Primary closure glaucoma? • PRIMARY ANGLE CLOSURE GLAUCOMA(PACG) includes a spectrum of conditions in which the peripheral iris moves forwards to block the openings of trabecular meshwork at the angle causing a rise of intraocular pressure. • The condition may manifest as an ophthalmic emergency.

• Unlike POAG the diagnosis largely depends on examination of anterior segment and careful gonioscopy. • Management requires an understanding of underlying pathophysiological mechanisms.

Normal angle

Closed angle

What are the Risk Factors? a. Age: age of presentation is about 60yrs, prevalence increases thereafter. b. Race: more common in south-east asians, chinese, eskimos but uncommon in blacks. c. Sex: significant predominance of females by a ratio of 4:1.

d. Refractive Error: More common in hypermetropes because of shallower anterior chamber. •

e. Family History: generally believed to be inherited. •

f. Systemic disorders: type II Diabetes is associated with decreased anterior chamber depth. •

g. Seasonal incidence: more common in

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Anatomical predisposing factors 1. Relatively anterior location of iris lens diaphragm secondary to short axial length. 2. Shallow anterior chamber. 3. Narrow enterance to chamber angle.

Primary angle closure

Precipitating factors I . Factors that produce mydriasis : a. Dim illumination b. Emotional stress c. Drugs (Mydriatics – anticholinergics ). II . Factors that produce miosis : strong cholinesterase inhibitor miotics. III . Sulpha based compounds that produce transient myopia due to lens swelling and forward movement of lens iris diaphragm.

MECHANISM a. RELATIVE PUPIL BLOCK

b.

IRIS BOMBE

Types of Angle Closure Glaucoma (Based on symptoms and Clinical Findings) 1. Primary angle closure glaucoma suspect 2. Sub-acute angle closure glaucoma (also called intermittent/ prodromal or subclinical glaucoma). 3. Acute angle closure glaucoma 4. Chronic Angle Closure Glaucoma

Primary angle closure glaucoma suspect 1. Symptoms are absent. 2. Slit lamp Biomicroscopy: a.Shallow anterior chamber and iris-lens Diaphragm is convex. b. Close proximity of iris to the cornea.

3. Gonioscopy: shows an an Occludable

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Angle in which the pigmented trabecular meshwork is not visible without indenta•

tion in atleast

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3 out of 4 quadrants.

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The drainage angle in

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such eyes is generally

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Grade II or less i.e.

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less than 20 degrees.

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Clinical course IOP may remain

Chronic angle

normal

closure (may Acute or subacuteangle closure

develop without passing through acute or subacute stage)

Treatment

Intermittent angle closure • Shallow anterior chamber with an occludable angle with a narrow angle recess in which physiological mydriasis precipitates a pupillary block resulting in sharp rise in IOP for a short period of time followed by spontaneous resolution.

Diagnosis • Based on characteristic history of unilateral headache, browache, blurring of vision on same side & unbroken colored halos around lights during episode (d/t corneal edema). • Between these attacks, eye is free of symptoms & only shows signs of a narrow angle recess, clumping of pigment in the angle or occasional PAS.

Treatment Prophylactic peripheral laser iridotomy

LPI

Acute angle closure • Caused by sudden occlusion of the entire angle with a resultant rise of IOP to extremely high levels(5060mmHg). • C/O severe unilateral headache, nausea & diminision of vision in a RED EYE. • O/E ciliary & conjuctival congestion, corneal edema, a shallow anterior chamber, & iris bombe with a vertically oval, mid-dilated

After resolution of corneal edema, a gonioscopically closed angle can •

be seen,i.e.

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extensive

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Iridocorneal

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synechiae.

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The optic disc may be hyperaemic or normal.

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Visual fields shows non-specific constriction. It may be constriction of upper field or nerve fibre bundle defect. •

Treatment

1. Careful history of symptoms relating to intermittent angle closure attacks in the other eye, use of prescription or non-prescription drugs which may precipitate attacks, and type of activity preceding the attack. 2. Examination of the affect -ed eye and other eye with attention to central and peripheral anterior chamber depth as well as the shape of the peri-

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3.Administration of oral isosorbide and one or more topical aqueous suppressants. Intravenous acetazolamide can be given according to the surgeon’s preference. 4.The pt lies supine to permit the lens to fall posteriorly with vitreous dehydration. 5. The eye is reassesed after 1 hour. IOP is usually decreased, but the angle usually remains appositionally closed. One drop of 2% or 4% pilocarpine is given and the pt reexamined 30 min later.

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If IOP is reduced and angle open

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Low dose pilocarpine + aq. Suppressants

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+ steroids.

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Eye quiet

Do LPI

If IOP unchanged or  and angle remains closed Suspect lens related angle closure With hold pilocarpine Do ALPI If eye quiets – Do LPI

Chronic Angle Closure Glaucoma • Asymptomatic, diagnosis is reached if IOP is chronically raised in eyes having synechial closure over at least 180 degrees. Changes in optic n. head & visual field may or may not be present.

MECHANISM :

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• Peripheral Anterior Synechiae (PAS) may develop with prolonged or recurrent acute or subacute attack leading to chronic angle closure glaucoma. •

• PAS in acute angle closure are broad based and are seen in superior quadrant and correlate with duration of acute attack. •

• Synechial closure is referred to as shortening of the angle – creeping angle closure. This condition can be prevented by timely peripheral iridotomy. •

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Treatment • Laser iridotomy to eliminate pupil block. • Medical therapy to treat any residual elevation of IOP. • If this fails, trabeculectomy.

Combined Mechanism Glaucomas • Combined mechanism glaucomas refers to condition in which both, open angle and angle closure components are present. • After successful treatment of angle closure glaucoma with iridotomy , eliminating all appositional closure the IOP still remains elevated. PAS may or may not be present. • An eye with open angle glaucoma may develop angle closure due to natural development of pupillary block or result

PProvocative tests: ROVO 1. Mydriatic Provocative test: topical Tropicamide 1% rise of IOT-8 mmHg/more is considered positive test. 2. Dark Room Provocative test: Exposure to dark for 60 – 90 min – rise of 8 mm Hg/more is considered positive test. 3. Prone Provocative test : Prone position for 60 min , rise of 8 mmHg/more is considered positive test. 4. Pilocarpine/Phenylephrine ProvocativeTest: 2% Pilocarpine and 10% Phenylephrine are instilled simultaneously every minute for 3 applications to achieve mid dilated pupil – rise of 8 mmHg/more is considered positive test.If negative repeat the test .

Management Goals • Identification of patients at risk of developing primary angle closure (PAC) glaucoma or to identify patients with PAC •

• To manage an acute attack

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• To prevent permanent damage to angle of anterior chamber •

• To ensure that patient leads a symptom free life •

• To observe for chronic IOP elevation,

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MEDICAL THERAPY • Approaches e. To reduce IOP f. To relieve the angle closure

a. Reduction of IOP • • ORAL THERAPY 1. Acetazolamide 2. Glycerol 3. Isosorbid • • INTRAVENOUS THERAPY 1. Mannitol 2. Acetazolamide • TOPICAL THERAPY 1. Pilocarpine 2. Beta-adrenergic blockers 3. Alpha 2 Adrenergic Agonist 4. Topical carbonic anhydrase inhibitor

b. RELIEF OF ANGLE CLOSURE : b. Relief of Angle Closure • 1. Pilocarpine 1 or 2 %

• 2. Topical thymoxamine 0.5% (Eserine and Echothiopate Iodide are not indicated) • 3. LASER PI • 4. If not possible then surgical / incisional iridectomy • 5. Lensectomy

Filtration procedures

POST-TRAB BLEB

Plateau Iris

Plateau iris configuration Plateau iris configuration is characterized by a near-normal-depth central anterior chamber,a flat iris profile, and crowding of the anterior chamber angle by the iris base. The IOP may be normal or elevated. The condition appears to be related to a forward displacement of the ciliary processes that causes anterior displacement of the peripheral iris and angle closure. Such closure occurs without a significant pupillary block component.

Plateau iris syndrome Plateau iris syndrome is defined as having a plateau iris configuration with a closed anterior chamber angle and usually with elevated IOP, which persists despite the elimination of any pupillary block component by a patent iridotomy. Intraocular pressure elevation that was present before iridotomy may persist; the

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