Optic nerve ultrastructure following amiodarone therapy.

Amiodarone has been implicated in the pathogenesis of optic neuropathy in several cases. However, that relationship is unclear, as subjects placed on amiodarone represent a high-risk group for various vasoocclusive accidents. In order to investigate the effect of amiodarone on the optic nerve, we examined histopathologically sections of the retrobulbar optic nerve obtained from an asymptomatic subject taking amiodarone. Lamellar inclusions were selectively found in the large axons. Amiodarone may have a chronic neurotoxic effect on the optic nerve via a drug-induced lipidosis. This neurotoxicity may be related to some of the acute forms of optic neuropathy described in the literature.