Historical Case Record Survey of Visual Acuity Data From Patients With Leber's Hereditary Optic Neuropathy (LHON)

Inclusion Criteria: 1. age ≥ 12 years 2. the onset of symptoms is dated after 1999 and is well documented (at least month of onset of symptoms is known for each eye) 3. at least two VA assessments are available within 5 years of onset of symptoms and prior to idebenone use 4. have a genetic diagnosis for LHON for one of the following mitochondrial DNA (mtDNA) mutations: G11778A, G3460A, T14484C Exclusion Criteria: 1. any participation in an interventional clinical trial after the onset of symptoms 2. any other cause of visual impairment (e.g. glaucoma, diabetic retinopathy, AIDS related visual impairment, cataract, macular degeneration, etc.) or any active ocular disorder (uveitis, infections, inflammatory retinal disease, thyroid eye disease, etc.) during the data collection period