PURPOSE: To determine whether the development of nonarteritic anterior ischemic optic neuropathy (NAION) is increased after receiving cataract surgery in a large general population. DESIGN: Nationwide, population-based, retrospective cohort study. METHODS: Setting: A 12-year nationwide, population-based, retrospective cohort study including 1,025,340 beneficiaries in the 2002-2013 Korean National Health Insurance Service database. Patients: We identified 40,356 patients who had undergone cataract surgery and matched non-cataract surgery controls (1:2) using estimated propensity scores in reference to age, sex, demographics, comorbidities, and co-medications. Observations: Kaplan-Meier curves and Cox proportional hazard models were generated to determine the risk of developing NAION in the cataract surgery group compared to the non-cataract surgery group. Main Outcome Measures: Effect (hazard ratio [HR]) of cataract surgery on NAION development. RESULTS: The 10-year incidence probability of NAION was 0.70% (95% confidence interval [CI], 0.55%-0.86%) in the cataract surgery group and 0.27% (95% CI, 0.25%-0.29%) in the non-cataract surgery group (P < .0001, log-rank test). The cataract surgery group had an increased risk of developing NAION compared to the non-cataract surgery group (HR = 1.80; 95% CIs, 1.46-2.21) even after adjusting for demographics, comorbidities, Charlson comorbidity index, and co-medications. CONCLUSION: Our results suggest that patients undergoing cataract surgery have an increased risk of NAION. (C) 2019 Elsevier Inc. All rights reserved.