Incidence of nonarteritic anterior ischemic optic neuropathy in adult Chinese: the Beijing Eye Study.

PURPOSE To determine the incidence of optic nerve damage due to nonarteritic anterior ischemic optic neuropathy (NAION) in the adult Chinese population. METHODS The Beijing Eye Study, a population-based, longitudinal study which included 4439 subjects (age 40+ years) in 2006, was repeated in 2006. In the follow-up examination, 3169 (71.4%) subjects participated. Optic disc photographs were assessed. Diagnostic criteria for incident NAION were a small optic disc, segmental pallor, and loss of retinal nerve fiber layer and visual field in the follow-up examination, with a normal optic nerve head appearance at baseline. RESULTS New NAION was found in one eye, with an incidence rate of 0.03+/-0.03% per 5 years (mean +/- standard error) (95% confidence interval: -0.03, 0.09), or about 1:16,000 subjects per year. CONCLUSIONS Within a 5-year period, new NAION may develop in 1 out of 3200 adult Chinese, or 1:16,000 adult Chinese per year.