Optic neuritis is an acute inflammatory disorder of the optic nerve commonly associated with multiple sclerosis. It is manifest by acute, unilateral visual loss, eye pain, typically with eye movement, decreased color or decreased contrast, visual field defect, and a relative afferent pupillary defect. Our patient presented with optic disc edema (rather diffuse/severe without hemorrhages), a less common presentation for acute, isolated optic neuritis. Differential diagnosis includes neuroretinitis, sarcoidosis, anad Leber hereditary optic neuropathy (LHON).