“My eye’s gone red and agony, I’m seeing haloes round lights and now I feel sick”

ACUTE ANGLE-CLOSURE GLAUCOMA is a sight-threatening ophthalmic EMERGENCY recognised by a cluster: a severely PAINFUL RED eye with BLURRED vision and HALOES around lights, plus HEADACHE and NAUSEA/VOMITING, and on face-to-face examination (a video call cannot confirm them) a fixed MID-DILATED (often oval) pupil, a HAZY/cloudy cornea and a hard eye, from a sudden rise in intraocular pressure. The key pitfall is being misled by the headache and vomiting toward a MIGRAINE, viral illness or GI bug while the eye complaint is downplayed — the discriminator is the painful red eye with haloes and blurring, so always ask about and examine the eye in anyone with headache/vomiting and unilateral eye pain. Distinguish it from other red eyes: conjunctivitis (gritty, discharge, normal vision), anterior uveitis (pain, photophobia, small/irregular pupil), scleritis (severe boring pain, autoimmune association) and keratitis (contact-lens-related, fluorescein uptake). Risk factors include HYPERMETROPIA (long-sightedness), older age, female sex, East or South Asian family origin (College of Optometrists), family history and a shallow anterior chamber, with precipitants of dim light/pupil dilation and pupil-dilating DRUGS (anticholinergics, tricyclics, some antihistamines, sympathomimetics, mydriatics, and topiramate, which can cause secondary angle closure within the first month) — so take a drug history. The action is EMERGENCY same-day ophthalmology assessment immediately, because sight is threatened within hours and urgent IOP-lowering and definitive laser peripheral iridotomy are needed (College of Optometrists Clinical Management Guidelines; RCOphth 2022); in primary care, recognise rapidly, refer/transfer to eye casualty, and give analgesia/antiemetic while arranging it. Communicate calmly with a frightened, severely-painful patient, explain why it cannot wait, advise against self-driving, and reassure that prompt treatment protects sight.