Acute angle-closure glaucoma !
Acute angle-closure glaucoma is a sudden rise in eye pressure when fluid cannot drain, causing a painful red eye and blurred vision; it is an emergency.
Updated 2026-10-29
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Why it happens
What it is
Sudden rise in intraocular pressure because the iris blocks the drainage angle of the eye, so aqueous humour cannot leave. It is an ophthalmic emergency that can cause permanent vision loss within hours to days.
Who gets it
More common in older adults, women, people of East Asian descent and people with long-sightedness (hyperopia). Narrow angles become narrower with age as the lens thickens.
Causes
- Pupillary block: the iris presses on the lens, aqueous builds up behind the iris, which bows forward and closes the angle
- Plateau iris configuration
- Lens-induced: a swollen (intumescent) cataract or a dislocated lens
- Drugs that dilate the pupil: anticholinergics, adrenergic agonists, some antidepressants and topiramate (which closes the angle by another mechanism)
Risk factors
- Age over about 50
- Female sex
- East Asian or Inuit ancestry
- Hyperopia and a short eye with a shallow anterior chamber
- Family history of angle closure
- Dim light, stress or pupil-dilating drops or drugs
Pathophysiology
Aqueous made by the ciliary body normally passes through the pupil into the anterior chamber and drains through the trabecular meshwork in the angle. When the iris is pushed against the lens or the angle, outflow stops and pressure climbs quickly. High pressure makes the cornea swell and cloudy, and squeezes the optic nerve head, which can lose fibres permanently.
Classification
- Primary angle closure (anatomical) or secondary (lens, inflammation, neovascularisation, drugs)
- Acute, intermittent or chronic
- Primary angle-closure suspect, primary angle closure, and primary angle-closure glaucoma once the optic nerve is damaged
Symptoms and signs
- Sudden severe eye pain and redness, usually in one eye
- Blurred vision and haloes around lights
- Frontal headache, nausea and vomiting
- Cloudy (oedematous) cornea
- Fixed, mid-dilated, oval pupil
- Eye that feels hard to the touch; shallow anterior chamber
Diagnosis
- Clinical
- Recognised by the combination of a red painful eye, cloudy cornea, fixed mid-dilated pupil and shallow chamber. Gonioscopy confirms a closed angle once the cornea clears; the other eye is examined, as it usually has a narrow angle too.
- Tests
- Tonometry shows markedly raised intraocular pressure. Visual acuity and slit-lamp examination. Blood tests are not needed for diagnosis.
- Imaging
- Anterior segment optical coherence tomography or ultrasound biomicroscopy can show the closed angle and its mechanism. Optic disc imaging after the attack documents damage.
Differential diagnosis
- Acute anterior uveitis
- Conjunctivitis
- Keratitis or corneal ulcer
- Scleritis
- Neovascular or inflammatory secondary glaucoma
- Migraine or cluster headache
Goal of treatment
Lower the pressure quickly to protect the optic nerve, reopen the angle by relieving the pupillary block, and protect the other eye.
Treatment
- Acute
- Pressure-lowering drops given together: beta-blockers, alpha-2 agonists and topical carbonic anhydrase inhibitors, plus topical corticosteroids for inflammation.
- Medical
- Systemic carbonic anhydrase inhibitors and, if needed, hyperosmotic agents. Miotics are added once pressure has fallen, except in lens-induced closure.
- Procedure
- Laser peripheral iridotomy: a small opening in the iris lets aqueous bypass the pupil. It treats the affected eye and is done prophylactically in the other eye.
- Surgical
- Lens extraction (cataract surgery) or a filtering operation when the angle stays closed or iridotomy is not possible.
- Follow-up
- Lifelong follow-up of pressure, angle and optic nerve, since chronic angle-closure glaucoma can follow.
Drugs for this condition
Complications
- Permanent optic nerve damage and visual field loss
- Central retinal vein occlusion
- Corneal decompensation
- Iris atrophy and lens opacities (glaukomflecken)
- Attack in the other eye
- Chronic angle-closure glaucoma
Prognosis
With prompt treatment, many eyes keep useful vision. Delay of more than a few hours raises the risk of permanent loss. Without prophylactic iridotomy, the other eye has a high chance of an attack.
Prevention
- Gonioscopy in people with risk factors, especially hyperopic older adults
- Prophylactic laser iridotomy for narrow angles judged at high risk
- Caution with pupil-dilating drugs in people known to have narrow angles
Test yourself
Think of the answer, then tap the question to see it.
What is the classic pupil finding in acute angle-closure glaucoma?
A fixed, mid-dilated, often oval pupil, with a cloudy cornea and a red eye.
What is the commonest mechanism of primary acute angle closure?
Pupillary block: the iris contacts the lens, aqueous builds behind it and pushes the peripheral iris forward over the angle.
Which laser procedure treats the attack and protects the other eye?
Laser peripheral iridotomy, which makes a bypass opening in the peripheral iris.
Which refractive error is a risk factor for angle closure?
Hyperopia (long-sightedness), because the eye is short and the anterior chamber shallow.
Why can acute angle closure be missed in the emergency room?
Headache, nausea and vomiting may dominate, so it is mistaken for migraine or a gastrointestinal illness.
Related conditions
Educational information, not medical advice. For any symptom, see a health professional.
Sources: Acute Angle-Closure Glaucoma (StatPearls (NCBI Bookshelf), 2026).
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