Atypical Leber hereditary optic neuropathy with a 34-year interval between vision loss in both eyes

PURPOSE: Leber hereditary optic neuropathy (LHON) is an inherited mitochondrial disease characterized by painless vision loss affecting both eyes. The disease usually develops in both eyes within weeks to months of onset. We report a case of LHON who presented with unilateral vision loss in childhood with an interval of more than 30 years between vision loss in the two eyes. OBSERVATION: A 43-year-old man presented with a 1-month history of vision loss in his right eye. At 9 years of age, his visual acuity in the left eye declined, and he had been treated with glaucoma eyedrops bilaterally at his eye clinic. At his first visit to our hospital, his BCVA was 0.15 in the right eye and 0.1 in the left eye, and critical flicker frequency was 16 Hz in the right eye and 15 Hz in the left eye, and he was negative for a relative afferent pupillary defect. The Goldman visual field showed central scotoma in both eyes. Fundus examination revealed slight redness of the right optic disc with meandering retinal small vessels, and the left optic disc had a slight pallor. Fluorescein angiography could not be performed because of liver dysfunction. OCT showed prominent bilateral thinning of the RNFL and retinal ganglion cell layer. Enhancement of the optic nerve was not apparent on orbital gadolinium-enhanced magnetic resonance imaging. Hematologic analysis revealed macrocytic anemia and low levels of vitamin B12 and folate. His mother had a presumptive diagnosis of LHON but did not receive genetic testing. A male cousin also had severe vision loss. Based on the likely family history of LHON, we performed genetic testing, which revealed the 11778 mitochondrial point mutation associated with this condition. CONCLUSION AND IMPORTANCE: We report a case of LHON with 34 years interval in vision loss in the fellow eye. LHON may develop in the second eye decades after its onset in the first. Detailed medical interviews and scrutiny, such as examination of family history, are warranted in consideration of LHON.