Acute angle closure: what to do before the ophthalmologist
- Emergency
A painful red eye with halos, vomiting, a hazy cornea and a hard eye is acute angle closure. The pressure is lowered at once, and laser is done in both eyes.
See it in 3D: Iris · Cornea · Ciliary body
What it is
In acute angle closure the peripheral iris blocks the drainage angle and the eye pressure rises very fast, damaging the optic nerve within hours. It happens in eyes with a narrow angle: long-sighted, older, more often women and people of East Asian ancestry. It can be triggered by dim light, dilating drops or drugs with anticholinergic or adrenergic effects. Treatment lowers the pressure with drugs and then opens a hole in the iris with a laser.
How to recognise it
- Severe eye pain, headache, nausea and vomiting.
- Blurred vision with coloured halos around lights.
- Red eye, hazy cornea, shallow anterior chamber, fixed mid-dilated pupil.
- Stony-hard eye on gentle palpation; very high pressure on tonometry.
- Bilateral angle closure after starting topiramate or a sulfa drug: a different mechanism (ciliary body swelling).
What to do at once
- Lay the patient flat and give analgesia and an antiemetic.
- Start topical pressure-lowering drops: a beta-blocker (timolol) and an alpha agonist (apraclonidine or brimonidine), unless contraindicated.
- Give a systemic carbonic anhydrase inhibitor (acetazolamide) unless contraindicated (sulfa allergy, kidney failure, sickle cell disease).
- If the pressure stays very high, an intravenous osmotic agent (mannitol) is given in hospital.
- Pilocarpine is added once the pressure starts to fall, because the iris does not respond while it is ischaemic.
- Stop any drug that may have triggered it, and call ophthalmology to arrange laser the same day.
Mistakes that cost sight
- It is often mistaken for migraine, a stroke or an abdominal illness because of the headache and vomiting: look at the eye.
- Dilating the pupil for a fundus exam rarely triggers an attack; it is more often provoked by systemic drugs or dim light.
- Drug-induced bilateral angle closure (topiramate) is not treated with pilocarpine or laser: the drug is stopped and the swelling treated.
- The other eye has the same anatomy and a high risk of an attack.
Next step / Initial management
- Emergency referral the same day after starting treatment.
- Definitive treatment: laser peripheral iridotomy in the affected eye and, as prevention, in the other eye.
- Lens extraction (cataract surgery) is an alternative that also widens the angle.
- Follow-up of pressure, optic disc and fields, since some patients go on to chronic glaucoma.
Test yourself
Think of the answer, then tap the question to see it.
Why is pilocarpine not the first drug in acute angle closure?
At very high pressure the iris sphincter is ischaemic and does not respond; it works once the pressure has fallen.
What is the definitive treatment of acute angle closure?
Laser peripheral iridotomy, in the affected eye and preventively in the other eye.
How is bilateral angle closure caused by topiramate treated?
By stopping the drug and treating the pressure; pilocarpine and iridotomy do not help because the mechanism is ciliary body swelling.
Elsewhere in DurgiPedia
Connections
See it in 3D3
The structures of Durgical's 3D anatomy where it is found.
In Pharmacology6
Educational content; not a clinical guideline and no substitute for assessment by a health professional. For sudden visual loss, severe eye pain, a chemical burn or an eye injury, go to an emergency department at once.
Sources: Acute Angle-Closure Glaucoma (StatPearls Publishing (NCBI Bookshelf), 2026).
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Representative model, for educational purposes only.