Angle-Closure Glaucoma

👁️ Angle-Closure Glaucoma (ACG)

Also known as Closed-Angle Glaucoma or Narrow-Angle Glaucoma

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🔍 Definition

Angle-closure glaucoma is a type of glaucoma where the anterior chamber angle between the cornea and iris is narrow or closed, impeding the outflow of aqueous humor, resulting in a sudden or chronic rise in intraocular pressure (IOP) and optic nerve damage.

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🔬 Classification

1. Acute Angle-Closure Glaucoma (AACG)

• Ophthalmic emergency

• Sudden onset with severe symptoms

• Rapid IOP rise

2. Chronic Angle-Closure Glaucoma

• Gradual closure of the angle

• Often asymptomatic until vision is affected

3. Intermittent Angle Closure

• Transient symptoms

• Triggered by low light, emotional stress, or drugs that dilate the pupil

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⚙️ Pathophysiology

• Aqueous humor is produced by the ciliary body → flows from posterior chamber → through pupil → anterior chamber → drains via trabecular meshwork in the angle.

• In angle-closure, the iris bows forward and blocks the trabecular meshwork, stopping drainage.

• This can be due to:

  • Pupillary block (most common mechanism)

  • Plateau iris configuration

  • Lens-induced crowding (e.g., in hyperopes or with cataracts)

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👁️‍🗨️ Clinical Features

🚨 Acute Angle-Closure Glaucoma:

• Severe eye pain

• Sudden decrease in vision

• Halos around lights

• Headache, nausea, vomiting

• Red eye with mid-dilated, non-reactive pupil

• Corneal edema (cloudy cornea)

• Very high IOP (>40–60 mmHg)

🐢 Chronic Angle-Closure Glaucoma:

• Often asymptomatic

• Gradual peripheral vision loss

• Intermittent blurring or eye ache

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🩺 Diagnosis

Test	Findings
Tonometry	Elevated IOP
Gonioscopy	Closed anterior chamber angle
Slit-lamp exam	Shallow anterior chamber, corneal edema
Optic disc exam	Cupping of optic nerve head
Visual field testing	Peripheral vision loss

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💊 Management

🔴 Acute Attack – Emergency Treatment

Goal: Rapidly lower IOP and relieve angle closure

Step 1: Medical Therapy

• Topical β-blocker (Timolol) – ↓ aqueous production

• Topical α-agonist (Apraclonidine) – ↓ aqueous production

• Topical Pilocarpine – Induces miosis to pull iris away

• Oral/IV Acetazolamide – Systemic carbonic anhydrase inhibitor

• IV Mannitol – Osmotic agent if IOP is extremely high

⚠️ Avoid dilating agents (e.g., atropine, phenylephrine)

Step 2: Laser Peripheral Iridotomy (LPI)

• Definitive treatment

• Creates an alternate path for aqueous humor flow

• Performed once the cornea clears and IOP is reduced

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🧊 Chronic Angle-Closure Management

• Laser Iridotomy (prophylactic in fellow eye too)

• Cataract surgery (removes lens-induced crowding)

• Laser iridoplasty or trabeculectomy if angle remains closed

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⚠️ Complications

• Permanent optic nerve damage

• Vision loss/blindness

• Corneal decompensation

• Peripheral anterior synechiae (PAS) formation

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🧠 Risk Factors

• Age >50 years

• Female sex

• Asian or Inuit ethnicity

• Hyperopia (farsightedness)

• Family history

• Shallow anterior chamber

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📌 Quick Comparison: Open vs. Angle-Closure Glaucoma

Feature	Open-Angle	Angle-Closure
Onset	Gradual	Sudden (acute) or chronic
Symptoms	None early	Pain, redness, vision loss
IOP	Mild-moderate ↑	Marked ↑ (40–60 mmHg)
Angle	Open	Narrow or closed
Pupil	Normal	Mid-dilated, fixed
Urgency	Chronic	Ophthalmic emergency

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📝 Summary

• Angle-closure glaucoma is caused by mechanical obstruction of aqueous humor drainage.

• Can be acute (emergency) or chronic (silent threat).

• Requires rapid IOP reduction, followed by laser iridotomy.

• Early detection and prophylaxis in high-risk individuals can prevent vision loss.