A 45-year-old man presented with progressive bilateral painless centra
l visual loss. He had a history of alcohol abuse and no family history
of visual impairment. The patient was initially diagnosed as having n
utritional deficiency amblyopia (NDA), but visual deterioration contin
ued despite a balanced diet and high potency B vitamin supplementation
. Ultimately, mitochondrial DNA analysis was positive for the II778 mu
tation of Leber's hereditary optic neuropathy (LHON).