Bitemporal Hemianopia Secondary to Acute Zonal Occult Outer Retinopathy

A 58-year-old man noticed shadows in the temporal visual field of each eye and photopsias within these scotomas for the past year. Formal visual fields demonstrated bitemporal hemianopia. MRI of the sella was normal, but fundus autofluorescence (FAF) demonstrated an area of hyperautofluorescence in the nasal retina of each eye corresponding to the loss of retinal pigment epithelium and photoreceptors. A diagnosis of acute zonal occult outer retinopathy was made based on the presence of trizonal involvement on FAF. This case is a reminder that bitemporal hemianopia can be caused by a retinopathy involving nasal retina in each eye, and FAF is a very useful test when assessing patients with suspected outer retinal disorders.