Volume 4, Issue 3

Introduction. Topiramate, a sulfamate-substituted anticonvulsant widely used for epilepsy and migraine prophylaxis, can cause bilateral secondary angle closure through ciliochoroidal effusion. Because the mechanism differs from pupillary block, the condition may be misdiagnosed and treated inappropriately. Case presentation. A 27-year-old woman presented with sudden bilateral blurred vision, ocular pain and headache 9 days after starting topiramate for migraine prophylaxis. Uncorrected visual acuity was 6/60 in the right eye and 6/36 in the left, with an acquired myopic shift of −3.50 D and −3.00 D. Intraocular pressure was 46 and 44 mmHg, and both anterior chambers were uniformly shallow with 360° angle closure on gonioscopy. Ultrasound biomicroscopy showed supraciliary effusion with anterior rotation of the ciliary body in both eyes. Topiramate was stopped, and she was treated with intravenous mannitol, topical aqueous suppressants, atropine and corticosteroids; pilocarpine and laser iridotomy were avoided. Intraocular pressure fell to 18 and 17 mmHg within 48 hours. By 2 weeks the myopic shift and effusions had resolved, the angles were open without synechiae, and uncorrected visual acuity was 6/6 in both eyes. Conclusion. Bilateral angle closure with an acute myopic shift in a patient recently started on topiramate should prompt immediate withdrawal of the drug and treatment directed at ciliochoroidal effusion rather than pupillary block.