Introduction Refers to inflamation of the optic nerve outside the eye usually unilateral Seen in multiple sclerosis Intermitting episodes lasting 2-8 weeks each relapse damages nerve, eventually leading to blindness Presentation Symptoms unilateral loss of vision pain with eye movement Evaluation Fundoscopic exam unremarkable Neuroimaging MR with contrast is the most sensitive test If patient is older than 60, biopsy temporal artery to rule out temoral arteritis Differential Temporal arteritis Treatment Medical IV and oral corticosteroids