Optic disc structure in anterior ischemic optic neuropathy.

The etiology of anterior ischemic optic neuropathy (AION), when not associated with giant cell arteritis, is usually unknown. Clinical, pathologic, and experimental studies have not determined a cause. The optic disc appearance in both the involved and normal fellow eye was studied in 51 patients with acute nonarteritic AION. The number of discs (both involved and fellow) without a physiologic cup was significantly greater than would be expected from normal population studies. The etiology of nonarteritic AION may be related to the anatomic configuration of the optic nerve.