AQP4 and Leber hereditary optic neuropathy: Oxygen therapy 1 g/ day, MTPN iv for 5 days, then oral PDN with tapering doses. After one month: BCVA RE = 20/ 40, BCVA LE = 20/ 400 with RAPD. Fundus LE: optic disc pallor; VF - centrocecal scotoma; OCT: RNFL thinning in the temporal sector and CGL decrease; MRI of the orbit: mild increased thickness and signal in the left optic nerve. Normal brain MRI, normal inflammatory tests, negative PCR. CSF exam: IgG oligoclonal bands present in CSF but not in serum, anti-AQP4 antibodies negative in CSF and serum. After one month: LE: without eye pain; optic atrophy despite the treatment.