Distended optic nerve sheaths in Leber's hereditary optic neuropathy.

Distension of the optic nerve sheaths is a feature of Leber's hereditary optic neuropathy (LHON) that has attracted attention only recently. We followed a patient with LHON for 23 years and obtained his eyes for pathological examination after death. We report the first histologic description of distension of the optic nerve sheaths, together with typical histopathological findings of LHON. Distension of the optic nerve sheaths could not be accounted for by any etiology other than LHON, although the precise pathogenic mechanisms remain enigmatic.