FFinalistSouthampton · 2027
Ophthalmology
AKT · Ophthalmology/Glaucoma

Acute angle-closure glaucoma

Pupillary-block closure of the drainage angle → acute IOP rise (emergency)

Overview

A sudden rise in intraocular pressure when the iris blocks the trabecular drainage angle (pupillary block). An ophthalmic emergency presenting with a painful red eye, haloes, a hazy cornea and a fixed mid-dilated oval pupil, often with nausea and vomiting. Risk factors: hypermetropia, age, female sex, dilation (dark rooms, mydriatics, anticholinergics).

Recognise

  • Acute severe eye pain and headache, blurred vision with HALOES around lights, nausea/vomiting
  • Red eye with a hazy/cloudy cornea, a fixed mid-dilated oval pupil, and a hard ('stony') globe
  • Precipitants: dim light, pupil-dilating drugs (mydriatics, anticholinergics, sympathomimetics, TCAs), hypermetropic (long-sighted) shallow-anterior-chamber eyes

Red flags

  • Painful red eye + haloes + nausea + fixed mid-dilated pupil = AACG — sight-threatening, refer immediately
  • Bilateral risk: treat the fellow eye prophylactically (laser iridotomy)

Differentials & how to tell them apart

Anterior uveitissmall (not dilated) pupil, AC cells, normal/variable IOP
Acute conjunctivitisdischarge, normal pupil/cornea/IOP, no haloes or nausea
Migraine/cluster headacheheadache without a hard red eye or mid-dilated pupil
Scleritisboring pain, deep redness, normal pupil and IOP
Acute angle-closure glaucoma — red eye, hazy cornea, mid-dilated pupil

Acute angle-closure glaucoma — red eye, hazy cornea, mid-dilated pupil

James Heilman, MD / CC BY-SA 3.0 — Wikimedia Commons

Investigations

Tonometry (IOP often 40–80 mmHg), gonioscopy (closed angle), slit-lamp (shallow AC, corneal oedema). Diagnosis is clinical/urgent.

Management

Emergency referral + IOP-lowering (pilocarpine + acetazolamide); definitive = laser iridotomy

  1. 1Admit/refer immediately for same-day ophthalmology. If admission is delayed, start emergency treatment: lie the patient flat (face up, no pillow), pilocarpine drops (2% blue/4% brown eyes), acetazolamide 500 mg, analgesia and an antiemetic.Gate: Pilocarpine works only once the iris sphincter is not ischaemic — at very high IOP the pupil may not respond until pressure is first lowered (acetazolamide/topical agents); avoid drugs that dilate the pupil
  2. 2Secondary care: IV acetazolamide + topical agents (beta-blocker, pilocarpine, steroid) to break the attack, then DEFINITIVE peripheral laser iridotomy to both eyes (the fellow eye is at risk); lens extraction/iridoplasty in some.
Pilocarpine 2% (blue eyes)/4% (brown) drops — constricts the pupil to pull the iris out of the angle
Acetazolamide 500 mg (oral or IV) — carbonic anhydrase inhibitor — reduces aqueous production
Topical beta-blocker, alpha-agonist, steroid — lower IOP and reduce inflammation in secondary care
Analgesia + antiemetic — symptomatic; lie the patient flat, face up

Key points

Painful red eye + haloes + vomiting + fixed mid-dilated pupil in a long-sighted older person = AACG. Treat both eyes — the fellow eye is anatomically primed to close.

Monitor & prognosis

IOP response; lifelong glaucoma surveillance after iridotomy.

Good if treated within hours; delay causes permanent optic-nerve damage.

Source: NICE CKS Glaucoma (RCOphth 2022; NICE NG81)