6 Oct 2026
Patient history
A 66-year-old woman presents with four hours of severe right-sided headache, nausea and repeated vomiting. She was referred as a possible abdominal emergency. Pressed further, she says her right eye aches and she sees coloured rings around lights.
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Acute angle-closure glaucoma
IV acetazolamide with topical agents, then laser peripheral iridotomy
Headache with nausea and vomiting frequently sends these patients down an abdominal or neurological pathway, and the diagnosis is missed until someone asks about the eye. The distinguishing features are all ocular: a red eye with circumcorneal injection, a hazy cornea from epithelial oedema, and a mid-dilated, oval, fixed pupil. That pupil is the crucial sign: a constricted pupil suggests anterior uveitis and a normal one suggests conjunctivitis, whereas mid-dilation is what occurs when the iris bunches into the drainage angle and blocks aqueous outflow. Haloes around lights are produced by corneal oedema diffracting light. The predisposing anatomy is hypermetropia, which gives a shallow anterior chamber and a crowded angle, and the two precipitants are both present here: dim light causing physiological pupil dilatation, and an antihistamine with anticholinergic activity doing the same pharmacologically. An intraocular pressure of 54 mmHg against a normal of 10 to 21 confirms it. Optic nerve damage begins within hours, so the pressure comes down now: intravenous acetazolamide to cut aqueous production, topical pilocarpine to constrict the pupil and pull the iris back out of the angle, a topical beta blocker and alpha agonist alongside, and the patient laid flat so the lens falls away from the iris. All of that is holding action. The cure is laser peripheral iridotomy, which gives aqueous a channel past the pupillary block, and the narrow occludable angle in her asymptomatic left eye is why it is done on both: the fellow eye is anatomically identical and has simply not met its trigger yet.