School and family based myopia education associations with myopia prevalence in Hefei high school students in the post-COVID-19 period

To investigate associations between multiple factors—including gender, parental myopia, outdoor activities, near work, and school/family-based myopia education—and myopia prevalence among high school students in Hefei in the post-COVID-19 period. A cross-sectional survey was conducted among 6475 senior high school students (aged 17–19 years) from 15 schools in Hefei, China, between March and May 2023. Visual acuity was measured using a standard logarithmic eye chart, and refraction was assessed via non-cycloplegic autorefraction with tropicamide-induced mydriasis. Myopia was defined as spherical equivalent (SE) < − 0.5 D. Self-reported questionnaires captured data on parental myopia, outdoor time, near work, sleep, and myopia prevention strategies. Data were analyzed using chi-square tests, tQUER-tests, and multivariate logistic regression, with sensitivity analyses accounting for potential overestimation due to non-cycloplegic refraction. Of 6414 participants (after exclusions), myopia prevalence was 85.3% (adjusted to approximately 82.5% in sensitivity analysis assuming 0.5 D overestimation). Females showed higher prevalence than males (88.9% vs. 82.9%; χ 2 = 46.434, p < 0.01). Parental myopia was associated with higher risk (χ 2 = 84.69, p < 0.01; adjusted OR = 2.20, 95% CI 1.75–2.85). Outdoor activities > 1 h/day were associated with lower prevalence (χ 2 = 110.5, p < 0.01; adjusted OR = 0.40, 95% CI 0.28–0.58), while prolonged near work (> 6 h/day in 55% of students) correlated with higher rates. Parental and school education on myopia prevention (e.g., promoting outdoor time, regulating screen exposure) was linked to lower severity, though adoption was low (17.2% parental, 36.5% school). High myopia prevalence was observed, associated with female gender, parental myopia, reduced outdoor time, and increased near work—factors that were commonly observed in this post-pandemic cohort (with behaviors consistent with patterns reported during the pandemic period). School- and family-based education were associated with myopia severity, but the cross-sectional design precludes causal inference (reverse causality is possible). Non-cycloplegic measurements may inflate estimates. These findings may inform targeted prevention strategies.