The early phase in Leber hereditary optic atrophy. 
Clinical, ophthalmoscopic, perimetric, and color vision tests and visual evoked responses were recorded in symptomatic and asymptomatic eyes in five members of a family with Leber hereditary optic atrophy.  The presymptomatic eyes showed abnormalities in the retinal nerve fiber layer.  Optic nerve dysfunction was found before central vision failed.  The appearance of degenerating retinal nerve fibers, particularly in the papillomacular bundle, was documented photographically in the weeks after the onset of visual symptoms.  Treatment with prednisone and hydroxocobalamin did not reverse or halt serious impairment of vision.