Aims To determine the age and sex-specific prevalence and incidence of non-arteritic anterior ischaemic optic neuropathy (NAION) in South Korea.

Methods This is a nationwide population-based study using data from the Korean national health claims database to identify patients with NAION using the registration programme database, which comprises ophthalmologist-confirmed NAION from 2011 through 2015. We evaluated prevalence and incidence rates using these data.

Results Among 25 816 797 of entire population 40 years of age or older, 26 167 patients had NAION (47.8% men) during the 5-year study period. The prevalence in the general population 40 years of age or older was 102.87 (95% CI 95.22 to 110.53) per 100 000 people. In men, it was 111.10 (95% CI 101.19 to 121.02), and in women, it was 94.64 (95% CI 89.25 to 100.03) per 100 000 people. The prevalence increased with advancing age and peaked at 70–74 years in men and 65–69 years in women. The incidence in the general population 40 years of age or older was 11.35 (95% CI 10.37 to 12.33) per 100 000 person-years. In men, it was 14.89 (95% CI 12.26 to 16.91), and in women, it was 9.92 (95% CI 8.85 to 10.99) per 100 000 person-years. The incidence increased with advancing age and peaked at 80–84 years in men and 70–74 years in women.

Conclusions The prevalence and incidence estimates of NAION are comparable with those of Caucasians. These detailed estimates could promote understanding of the disease’s pathophysiology and allow for appropriate planning within the healthcare system.