CASE REPORTS: Presumed topiramate-induced retinopathy in a 58-year-old woman

Abstract

We present a case of presumed topiramate-induced retinopathy in a 58-year-old woman who presented with progressive, bilateral visual loss following a 3- to 4-year history of oral topiramate intake for migraine. She reported difficulty with light adaptation, hemeralopia, and color desaturation. Her best-corrected visual acuity was 1/60 (20/1200) in the right eye and 6/18 (20/60) in the left eye, and she performed poorly on Ishihara color plate testing. Anterior segment examination was normal; dilated funduscopy showed mild macular pigmentary changes. Optical coherence tomography revealed subtle thinning and reduced reflectivity of the subfoveal ellipsoid zone and interdigitation zone bilaterally, associated with increased foveal autofluorescence. Humphrey visual field 24-2 revealed central defects. Electrodiagnostic testing showed a reduced and delayed b-wave and a normal a-wave on photopic full-field electroretinogram (ERG), with normal scotopic responses; multifocal ERG revealed reduced responses in the inner 10° in both eyes. She underwent extensive investigations including whole-body computed tomography and positron emission tomography scan, magnetic resonance imaging of the brain, uveitis screening, retinal autoantibody testing, and genetic testing on the retinal dystrophy panel to rule-out other causes for her presentation, all of which were normal or negative.