Acute Angle-Closure Glaucoma Emergency

Acute primary angle-closure glaucoma (APAC) results from pupillary block with iris-lens apposition trapping aqueous humor in the posterior chamber, bowing the iris forward and contacting the trabecular meshwork. Asian and Inuit populations and short hyperopic eyes with shallow anterior chambers are at highest risk. Triggers include dim light, anticholinergics, sympathomimetics, and topiramate.

Patients present with sudden severe unilateral ocular pain, frontal headache, blurred vision with halos around lights, nausea, and vomiting. Examination reveals red eye with circumcorneal injection, cloudy edematous cornea, mid-dilated non-reactive pupil, shallow anterior chamber, and tactile firm globe. Tonometry shows IOP 40-80 mmHg. Gonioscopy confirms closed angle, contralateral eye usually shows narrow occludable angle.

Initial medical management lowers IOP urgently with topical pilocarpine 1-2% (after corneal edema clears) and adjuncts including timolol 0.5%, brimonidine, dorzolamide drops, oral acetazolamide 500 mg, and IV mannitol 1-2 g/kg for refractory cases. Once IOP is reduced and corneal edema clears, definitive treatment is laser peripheral iridotomy (LPI) to create a hole in peripheral iris, equalizing pressure between chambers. Prophylactic LPI of fellow eye is mandatory. Persistent angle closure may require lens extraction or surgical iridectomy. Visual prognosis depends on duration of attack and IOP severity.