Angle Closure Glaucoma

Angle-Closure Glaucoma: The Ocular Emergency That Can Be Cured with Cataract Surgery

Angle-closure glaucoma (ACG) is an ophthalmic emergency in which aqueous humor drainage is suddenly blocked, elevating intraocular pressure (IOP) to dangerous levels (>40 mmHg). Unlike chronic (open-angle) glaucoma, ACG can cause irreversible vision loss within hours if left untreated.

Anatomical Key:

The iridocorneal angle (between the iris and the cornea) closes, preventing aqueous humor from escaping through the trabecular meshwork.

This occurs in eyes with predisposing anatomy:

Narrow anterior chamber.

Bulging iris (common in hyperopes and Asians).

Large lens (due to early cataract or nuclear sclerosis).

Relationship between Angle-Closure Glaucoma and Cataracts

The lens plays a key role in the development of GAC:

✔ Increase in size with age: The lens grows and pushes the iris forward, narrowing the angle.

✔ Advanced cataracts: These accelerate this process by increasing the volume of the lens.

Crucial fact:

50% of patients with acute GAC have significant cataracts.

Why is it Urgent to Detect GAC Early?

1. Symptoms of an Acute Attack (Medical Emergency)

Intense eye pain (like a nail in the eye).

Sudden blurred vision (halos around lights).

Red eye and fixed pupil in mydriasis.

Nausea and vomiting (due to vagal reflex).

2. Consequences if left untreated: Irreversible optic nerve damage within 24-48 hours.

Permanent blindness due to optic nerve atrophy.

3. Preventing Chronic GAC

Progressive angle closure (without acute symptoms) also causes silent damage.

Diagnosis: Key to Saving Vision

Gonioscopy: Examines the iridocorneal angle (narrow or closed).

Tonometry: Measures IOP (normal: 10-21 mmHg; in acute GAC: >30 mmHg).

Anterior segment OCT: Quantifies angle narrowing.

Pachymetry: Evaluates corneal thickness (thin corneas are more vulnerable).

At-risk population:

Women over 50 years of age (2-4 times more common than men).

Hyperopes (small eyes with narrow anterior chambers).

Asian and Native American individuals (predisposing ocular anatomy).

Treatments: From Immediate Control to Definitive Cure

A. Initial Treatment (Emergency)

✔ IOP-lowering medications:

Acetazolamide (IV or oral).

Mannitol (IV).

Hypotensive drops (timolol, brimonidine, pilocarpine).

✔ YAG laser iridotomy:

Creates a hole in the iris to allow aqueous humor flow.

Effective in 75% of cases.

B. Definitive Treatment: Cataract Surgery

Lens extraction (phacoemulsification) + IOL implantation:

Removes the enlarged lens that was blocking the angle.

Opens the iridocorneal angle in 90% of cases (Journal of Glaucoma).

Advantages:

Cures the anatomical mechanism that caused the GAC.

Improves vision by removing the cataract.

Evidence:

Cataract surgery reduces IOP by 30% in eyes with narrow angles (NEJM).

In patients with chronic GAC, phacoemulsification prevents future attacks.

Importance of Prevention

Routine gonioscopy in patients with:

Hyperopia.

Family history of GAC.

Early cataract.

Prophylactic laser iridotomy in eyes with asymptomatic narrow angles.

Patient education: Recognize symptoms of an acute attack.

Serious Consequences of Untreated Angle-Closure Glaucoma: Corneal Decompensation and Irreversible Blindness

If angle-closure glaucoma (ACG) is not treated promptly, complications rapidly progress to severe and irreversible eye damage, with two devastating consequences:

1. Corneal Decompensation (Acute Edema)

Why does it occur?

Extremely high intraocular pressure (IOP) (>40 mmHg) compensates for the cornea, preventing the endothelial cells (responsible for keeping it clear) from functioning.

Excess fluid invades the cornea, causing acute corneal edema.

Symptoms:

Excruciating pain (due to distension of corneal nerve endings).

Severe corneal opacity (the cornea turns white, like "ground glass").

Extreme photophobia and tearing.

Sequelae:

Chronic residual pain: Even if IOP is controlled, endothelial damage may persist.

Urgent corneal transplant: In severe cases with massive endothelial cell loss.

2. Blindness Due to Irreversible Optic Nerve Damage

Mechanism:

Elevated IOP disrupts blood flow to the optic nerve, causing axonal atrophy.

Nerve fibers die within hours if IOP exceeds 50 mmHg.

Clinical findings:

Cave-in of the optic disc (visible in the fundus).

Total loss of light perception (absolute blindness).

Why is it irreversible?

The optic nerve does not regenerate. Once damaged, vision loss is permanent.

Alarming Facts:

50% of untreated patients lose vision in the affected eye within 48 hours (Journal of Ophthalmology).

Chronic corneal edema post-GAC requires transplantation in 30% of cases (Cornea Journal).

Neuropathic pain from corneal damage can be untreatable even with medications.

Key Message: Prevention and Early Treatment Save Vision

✔ If you have symptoms of acute GAC (pain + blurred vision + nausea): It's an emergency! Go to an ophthalmology emergency room.

✔ If you have asymptomatic angle closure: A YAG laser iridotomy can prevent angle closure.

✔ If you already have a cataract and angle closure: Early cataract surgery is curative and prevents glaucoma.