Clinical reasoning: a 42-year-old man with sequential monocular visual loss.

S. Prasad, MD H.E. Moss, MD, PhD E.B. Lee, MD, PhD C.C. Glisson, DO S.L. Galetta, MD SECTION 1 In April 2005, a 42-year-old African American man developed insidious, painless visual loss in the left eye which quickly progressed over several weeks. There was no significant medical history. Family history revealed hypertension and diabetes, but no autoimmune disorders, brain tumors, or vision loss. He was a restaurant manager, smoked 1⁄2 pack of cigarettes daily, consumed alcohol rarely, and did not use illicit drugs. He presented to another institution, where he was found to have 20/100 acuity, dyschromatopsia, and a relative afferent pupillary defect in the left eye. The left optic nerve head was mildly swollen, without hemorrhage or exudate. Humphrey visual fields of the left eye revealed a dense superior altitudinal defect with a less prominent inferior arcuate defect. The right eye field was full. He was thought to have idiopathic optic neuritis. He was treated briefly with oral corticosteroids, but his vision in the left eye never improved.