INTRODUCTION: Simultaneous bilateral angle-closure glaucoma is a potentially blinding disease. From 2001 to 2007, over 100 cases of Topiramate-associated bilateral acute angle glaucoma (TA-ACG) were reported. We report the first known case in the Philippines.

CASE REPORT: A 42-year old Filipino woman diagnosed with migraine presented with the sudden blurring of vision, with generalized headache after her second dose of 25mg Topiramate. Visual acuity was decreased to 20/200 in each eye. Intraocular pressures  (IOP) were elevated to OD 50mmHg and OS 55mmHg with shallow anterior chambers and 360 degree angle closure on gonioscopy. Stat doses of mannitol, acetazolamide, brimonidine, and latanoprost were given. Topiramate was discontinued. Laser iridotomy was performed with note of an immediate drop in IOP to OD 24mmHg and OS 18 mmHg. On the day of discharge, the patient's third day of admission, IOP had returned to 12 mmHg OU and best-corrected vision had improved to 20/20 in both eyes. B-scan ultrasonography confirmed choroidal thickening in both eyes.

DISCUSSION: Topiramate associated acute angle closure glaucoma (TA-AACG) as an idiosyncratic adverse effect was first reported by Banta et al in July 20018 with shallow anterior chambers, relative lens thickening, and 360° ciliochoroidal detachments in both eyes on A- and B-scan ultrasonography. Angle-closure was believed to result from the anterior rotation of the ciliary process and not from pupillary block, rendering laser iridotomy ineffective. Signiñicant lens thickening has been shown in TA-AACG. It is thought to result in part from relaxation of the zonules due to anterior ciliary rotation and ciliary edema, and from a direct drug effect. Myopia resulting from this is characteristic of TA-AACG and may persist from days to weeks after discontinuation of topiramate. The management of TAAACG requires stopping the drug. As TA-AACG and transient myopia usually resolves within days to weeks after stopping Topiramate, medical treatment with topical cycloplegic agents, topical beta-blockers and oral pressure-lowering agents often suffice as an interim measure. However, more invasive options such as laser iridotomy should be considered when significant pupillary block angle closure is present.

SUMMARY: Topiramate may be associated with acute angle-closure glaucoma wherein, in the Filipino patient, pupillary block may be present and should be addressed by laser iridotomy when possible.