Fine structure of experimental cyanide optic neuropathy.

Within 48 hours after an intraperitoneal injection of sodium cyanide, abnormalities are evident in the retrobulbar portion of rat optic nerves. Electron microscopy initially shows swelling of astrocytes but progressively increasing damage, primarily to axones, is evident later. Six weeks after intoxication the retrobulbar segment of the nerves are devastated but the retinas and prechiasmal portion of the nerves have minor, and presumably secondary, lesions.