Right optic nerve (A) of a patient with acute LHON-related vision loss showing mild hyperemia, blurring of the disc margin, and elevation of the optic nerve head from swelling of the peripapillary retinal nerve fiber layer. LHON-related vision loss in the left eye had occurred 6 months prior leading to prominent temporal optic nerve pallor (B) from atrophy of the retinal nerve fiber layer. Leber hereditary optic neuropathy: current perspectives: Meyerson C, Van Stavern G, McClelland C - Clinical ophthalmology (Auckland, N.Z.) (2015). Not altered. CC.