Stroke Rate, Subtype, and Cardiovascular Risk Factors in Nonarteritic Anterior Ischemic Optic Neuropathy: A Population-Based Study

BACKGROUND: Nonarteritic anterior ischemic optic neuropathy (NAION) is a common cause of acute optic neuropathy in adults and is associated with vascular risk factors. Owing to the overlapping risk factor profiles between NAION and cerebral stroke, previous studies have produced conflicting results with regard to NAION as an independent risk factor for stroke. METHODS: A retrospective chart review was conducted using the Rochester Epidemiology Project database to identify all cases of NAION occurring among Olmsted County, Minnesota residents from January 1, 1990, through December 31, 2016. Stroke events were characterized using clinical and radiologic data. Comparison was made to an age- and sex-matched control group with similar vascular risk factors. RESULTS: One-hundred four patients with NAION and 104 control subjects were analyzed. Median age at diagnosis was 65 years (range, 40-90 years). Thirteen patients (13%) with NAION and 10 controls (10%) had symptomatic strokes after the age of 40 years. Among patients with NAION, 6 (46%) suffered a stroke before the diagnosis of NAION, 5 (39%) at least 5 months after the NAION diagnosis, and 2 patients (15%) suffered strokes both before and after the NAION. The cumulative probability of symptomatic strokes for patients with NAION was not significantly different than for controls (hazard ratio = 1.50, 95% confidence interval: 0.66-3.42; P = 0.34). There were no cardioembolic strokes within 1 month of the NAION diagnosis. The mechanism of symptomatic strokes did not differ between the 2 groups. CONCLUSIONS: NAION does not confer an increased risk of symptomatic stroke beyond the risk posed by age and existing vascular risk factors.