[Leber's hereditary optic neuropathy with onset at the age of 54 years].

We report a 55-year-old Japanese man who had an onset of bilateral progressive blurring of vision at age 54 years. His younger sister had diminished visual acuity since 14 years of age. On neurologic examination, bilateral optic atrophy was present. He could only count the digit numbers at 40 cm-distance with his right eye, and the visual acuity of the left eye was 0.08. Otherwise, neurologic examination was unremarkable. The PCR analysis of mitochondrial DNA prepared from whole blood revealed a G to A mutation at the nucleotide 11,778; the so-called Wallace's mutation. He was diagnosed as Leber's hereditary optic neuropathy. It is rare to see a patient with LHON with the onset after 50 years of age.