Walsh & Hoyt: Arteritic Anterior Ischemic Optic Neuropathy (AAION)

Although it often produces a severe and devastating optic neuropathy, GCA is the cause for AION in a relatively small minority (5.7%) of cases, with an estimated annual incidence in the United States of 0.57 per 100,000 over age 60. AION is, however, the most commoncause of visual loss in GCA, accounting for 7183% of cases, with retinal artery occlusion, choroidal ischemia, and PION less common. The mean age of onset for AAION is 70 years, with only rare occurrence under age 60. GCA occurs more frequently in women and with increasing age. It is most common in Caucasians and is unusual in African American and Hispanic patients. Liu et al. reviewed 121 consecutive temporal artery biopsies, assessing the rate of positive biopsies by ethnic background: 19/66 (29%) of Caucasianpatien ts had positive biopsies, compared with 0/40 Hispanic patients and 0/6 African-Americans.