Join UMDF as we mark Leber hereditary optic neuropathy day! 

Leber hereditary optic neuropathy (LHON) is a rare inherited mitochondrial disorder. Its primary symptom is sudden, painless loss of central vision. The typical onset pattern is for one eye to become affected, then the other eye to begin losing vision within a few weeks or months; though in rare cases, the interval between eyes can be years or decades. Onset begins with a small scotoma (blurry spot) in or around the center of vision that rapidly gets larger over about eight months, then stabilizes. The person affected experiences profound vision loss and legal blindness (visual acuity worse than 20/200). There is a wide range of outcomes in terms of how much peripheral vision remains, but most individuals affected by LHON retain some peripheral vision and never become totally blind.