Losing Weight, Losing Sight: Acute Bilateral Angle-Closure Glaucoma Triggered by Topiramate for Weight Loss

Abstract

Acute angle-closure glaucoma (AACG) is a sight-threatening emergency, with approximately one-third of cases triggered by medications. The most common mechanism of angle closure is pupillary block. Topiramate, commonly used for migraines and epilepsy, is a rare cause of AACG that occurs due to a different mechanism: choroidal effusion and anterior displacement of the lens-iris diaphragm. This report presents a 22-year-old woman who experienced sudden bilateral blurry vision without pain or redness one week after starting topiramate for weight loss. Her corrected visual acuity was 20/100 bilaterally (-9.00-3.00x180 /-10.50-4.00x180), with a myopic shift (previous refraction: +1.25 -2.25x180 /+2.00 -4.00x180) and intraocular pressure (IOP) of 40/44 mmHg. Gonioscopy revealed 360º iridotrabecular contact, and B-scan ultrasonography confirmed bilateral uveal effusion, leading to the diagnosis of topiramate-induced AACG. Immediate discontinuation of topiramate and treatment with cycloplegics for posterior displacement of the lens-iris diaphragm, aqueous suppressants, and topical steroids resulted in complete resolution, with her visual acuity returning to 20/20 and IOP normalizing to 10 mmHg in both eyes. This case underscores the importance of a thorough medication history in patients with AACG and of recognizing rare secondary causes when features are atypical – such as younger age, bilateral involvement, myopic shift, and absence of predisposing anatomy. Topiramate-induced angle closure, though uncommon, is increasingly reported with its wider use, including in weight-loss regimens. Importantly, it is a potentially reversible condition if promptly diagnosed and with drug discontinuation.