Association between ambient air pollution and prevalence of myopia in Korean men

Ambient air pollution may contribute to the growing burden of myopia, but evidence from large population-based studies remains limited. We evaluated the association between long-term exposure to ambient air pollution and the prevalence and severity of myopia in young Korean men. We analyzed nationwide military conscription examination data from 2010 to 2020, including 1,671,826 nineteen-year-old men residing in seven metropolitan cities. Participants without educational attainment data or living outside major urban areas were excluded. We examined the association between district-level 3-year average concentrations of particulate matter (PM₂.₅ and PM₁₀) and nitrogen dioxide (NO₂) with the prevalence and severity of myopia using logistic regression models adjusted for individual and district-level covariates. Sensitivity analyses considered 1- and 6-year exposure averages. Higher NO₂ exposure was associated with increased odds of myopia (OR per IQR: 1.262; 95% CI: 1.254–1.270), with stronger associations for high myopia (OR per IQR: 1.354; 95% CI: 1.342–1.366), in models adjusted for individual-level covariates. A clear dose-response pattern was observed across NO₂ quartiles. PM₁₀ also showed positive but weaker and less consistent associations, with slightly stronger links to low myopia. In contrast, PM₂.₅ demonstrated consistent inverse associations, likely reflecting temporal confounding due to limited data availability. Sensitivity analyses yielded similar results. Long-term exposure to NO₂ and PM₁₀ may contribute to both the development and progression of myopia, with NO₂ showing particularly strong associations for high myopia. Further longitudinal studies are warranted to clarify these relationships and inform preventive strategies.