Late onset LHON: report of two cases with successful recovery of vision

Leber hereditary optic neuropathy (LHON) is a mitochondrial genetic disorder typically characterized by subacute vision loss in young males, whereas late-onset cases (> 40 years) are less common and are often triggered by toxic or nutritional factors. This case series reports two cases of late-onset LHON in patients who experienced significant visual recovery after idebenone treatment. The first case involved a 64-year-old female smoker with folic acid deficiency and the m.3460G > A variant, with progressive improvement in best-corrected visual acuity (BCVA) and visual field (VF) after starting idebenone (900 mg/day) and folic acid supplementation, with recovery persisting even after drug discontinuation. The second case describes a 71-year-old woman carrying the m.14484T>C variant and a heterozygous NQO1 polymorphism who showed gradual and continuous visual improvement starting 12 months after onset, despite genetic factors that might theoretically limit idebenone efficacy. These cases highlight the importance of considering LHON in the differential diagnosis of subacute visual loss, regardless of age. Furthermore, they suggested that idebenone could be effective across different genetic backgrounds and in the presence of various triggering factors. The observed outcomes emphasize the need for long-term clinical evaluation as therapeutic benefits may manifest gradually and persist over time, even after treatment cessation.