WHAT IS ANGLE-CLOSURE GLAUCOMA?

Angle-closure glaucoma, also known as closed-angle glaucoma, manifests as a forward bulge of the iris that narrows or obstructs the drainage angle between the cornea and iris. As a result, the eye's pressure rises and fluid cannot flow through it.

PATHOGENESIS: Angle-closure glaucoma develops when the iris moves forward, obstructing the aqueous humor's ability to exit the eye through the trabecular meshwork. The pressure inside the eye keeps rising which could lead to damage to the optic nerve. The damaged optic nerve can cause blindness if it is not treated.

PREDISPOSING FACTORS: African Americans, Asians, and women are at increased risk.

CLINICAL FEATURES: The presentation may be chronic or acute.

1. Symptoms

a) Chronic angle closure glaucoma: Patients may be asymptomatic, or they may report a dull ache and blurred vision.

b) Acute angle closure glaucoma: Patients report severe ocular pain, blurred vision, seeing halos around lights, lacrimation, nausea, vomiting, and headache.

2. Physical examination findings vary according to presentation.

a) Chronic angle closure glaucoma: The patient’s pupils are normal. The intraocular pressure is normal to elevated, and the cup: disc ratio is increased.

b) Acute angle closure glaucoma is characterized by lid edema, conjunctival hyperemia, and circumcorneal injection.

— The cornea appears cloudy as the result of microcystic edema.

— The anterior chamber is shallow and cell, and flare (i.e., hazy fluid), secondary to an inflammatory reaction, is noted on slit-lamp examination.

— The pupil is midsized, fixed, and often ovoid.

— The intraocular pressure is markedly elevated.

DIFFERENTIAL DIAGNOSES include anterior uveitis, miotic-induced glaucoma, neovascular glaucoma, and traumatic glaucoma.

EVALUATION: The diagnosis is usually based on the clinical scenario.

THERAPY

1. Chronic angle closure glaucoma is treated with topical medications, peripheral iridectomy, or laser iridotomy on an outpatient basis.

2. Acute angle closure glaucoma is an emergency. The main goal of treatment is to reduce the intraocular pressure (Given below).

Pharmacologic Management of Acute Angle Closure Glaucoma

1. Hyperosmotic agents are used to drawing fluid back into the blood by increasing the osmolarity of the blood. These agents must be used with caution in patients with congestive heart failure or renal failure.

a) Oral agents include 50% glycerin (0.1 to 0.15 g/kg) or isosorbide.

b) Intravenous agents include mannitol 20% (1 to 2 g/kg over 45 minutes).

2. Carbonic anhydrase inhibitors are used to reduce the production of aqueous humor by the ciliary body. Acetazolamide (500 mg) is administered intravenously, followed by 500 mg orally, and then 250 mg orally every 6 hours.

3. Beta Blockers increase aqueous outflow. Timolol 0.5% (one drop every 12 hours)

4. Miotics constrict the pupil and increase the flow of aqueous humor through the trabecular meshwork. Pilocarpine 2% to 4% solution (one drop) is the agent of choice, except in the setting of recent eye surgery.

5. Corticosteroids are used to reduce inflammation. Prednisolone acetate 1% (one drop every 4 to 6 hours) is the agent of choice.

6. Antiemetics should be used to control nausea and vomiting, as this can increase intraocular pressure.

DISPOSITION

1. Chronic angle closure glaucoma: Regular eye examinations by an ophthalmologist are needed for proper management and care.

2. Acute angle closure glaucoma: An Ophthalmologist should be consulted upon recognition of the condition for further management.