Chiasmopathy?

A 57-year-old man presented with progressive visual loss in both eyes, bitemporal field defect, and a history of poor nutrition, alcohol abuse, and excessive cigar smoking. Magnetic resonance imaging was normal. The visual acuity and field defect improved with supplementation with vitamins and reduction of alcohol and tobacco consumption. A diagnosis of toxic optic neuropathy was made. The authors discuss the differential diagnosis of bitemporal/pseudobitemporal field defects and the diagnosis and treatment of toxic optic neuropathy.