Leber's hereditary optic neuropathy and the pupil

Excerpt

Leber's hereditary optic neuropathy (LHON) is a rare but interesting and mysterious disease. Defects of the mitochondrial genome have been identified as the underlying causative lesion [7], and LHON has now become a popular target for clinical research. In 1995 Wakakura and Yokoe suggested that in LHON visual function was more severely damaged than pupillary function [6]. They compared pupillary light reflexes of 13 patients with LHON, 19 patients with optic neuritis, 18 patients with anterior ischemic optic neuropathy (AION) and 25 normal subjects. Optic neuritis and AION patients differed from normal controls significantly; LHON patients did not. They concluded that the retinal W-ganglion cells, those small cells that are thought to be responsible for pupillary light reaction, must be spared in LHON. It was not long before a clinician examining a patient with optic atrophy of unknown origin began to think: This person has such a good pupillary light response; it must be LHON. …