INCIDENCE OF NONARTERITIC ANTERIOR ISCHEMIC OPTIC NEUROPATHY

PURPOSE: Nonarteritic anterior ischemic optic neuropathy is the most c ommon acute optic nerve disease of adults over age 50 years. This stud y determined the incidence of acute nonarteritic anterior ischemic opt ic neuropathy in the circumscribed population of Olmsted County, Minne sota. METHODS: This was a retrospective study of the incidence of acut e nonarteritic anterior ischemic optic neuropathy between 1981 and 199 0. The Rochester Epidemiology Project medical records linkage system f acilitates identification of the medical records of virtually all Olms ted County residents with a given diagnosis. All cases of acute nonart eritic anterior ischemic optic neuropathy that fulfilled certain inclu sion and exclusion criteria were identified. RESULTS: Twenty-two cases in 21 patients (11 men and 10 women) were recorded. The crude annual incidence rate was 10.3 per 100,000 individuals (95% confidence interv al [CI] = 5.1 to 18.4). When adjusted to the age and sex distribution of the 1990 United States white population, the incidence rate was 10. 2 per 100,000 (95% CI = 6.5 to 15.6). At diagnosis, the median age was 72 years, mean visual acuity was 20/200 in the affected eye, and the most common visual field defect was an altitudinal deficit (10 cases). CONCLUSIONS: Although results of this small study should be interpret ed cautiously, extrapolation of our findings to the United States whit e population indicates that nearly 5,700 new cases of acute nonarterit ic anterior ischemic optic neuropathy may be expected to occur each ye ar in this group.