While ethambutol optic neuropathy usually causes central or cecocentral scotomas, bitemporal visual field defects also have been reported. The pathogenesis of the bitemporal hemianopia has not been established. This article describes magnetic resonance imaging abnormalities involving the optic chiasm in a patient with bitemporal visual field loss. To our knowledge, these neuroimaging findings have not been previously described in association with ethambutol therapy.
Neuro-Ophthalmology Section, Division of Neurology, Departments of Medicine, Ophthalmology and Vision Sciences (VBO, JAS, SAA, ANES) and Medical Imaging (RIF), University Health Network, University of Toronto, Toronto, Ontario, Canada.
Address correspondence to Arun N.E. Sundaram, MD, MSc, FRCPC, Neuro-Ophthalmology Section, Division of Neurology, Department of Medicine, Ophthalmology and Vision Sciences, University Health Network, University of Toronto, 399 Bathurst Street, Toronto, Ontario, Canada M5T 2S8; E-mail: email@example.com
The authors report no conflicts of interest.