Recurrent ischemic optic neuropathy*

Abstract

Idiopathic ischemic optic neuropathy, presumed infarction in the retro-laminar segment of the optic nerve, is bilateral in as many as 50% of cases, but rarely occurs twice in the same optic nerve. We found only four anecdotal references to such recurrent involvement among 328 cases reported in the medical literature. Our patient, a 71-year-old man had two distinct episodes of infarction in the right optic nerve, each causing a distinct defect in the visual field as well as optic disc swelling. The rarity of recurrent symptoms affecting the same optic nerve may relate to mechanical factors. The initial infarct, by reducing the number of nerve fibers traversing the scleral canal, may decompress the remaining fibers and protect them from further irreversible damage. Thus, mechanical compression of optic nerve fibers within the scleral canal is implicated as a factor, in addition to vascular disease in the pathogenesis of ischemic optic neuropathy.