Real-world evidence on childhood refractive errors in a developed coastal region of China: a multi-center analysis of 4.47 million school-based screening encounters in Southern Fujian.

BACKGROUND: Despite rapid economic development in coastal China, the alignment between socioeconomic growth and pediatric eye health remains poorly understood. School-based screening may provide an opportunity to bridge this knowledge gap, yet large-scale, real-world evidence from diverse urban-rural gradients is scarce. METHODS: This cross-sectional study analyzed 4.47 million valid screening encounters from Xiamen, Quanzhou, and Zhangzhou (2021-2024). Visual acuity (VA) and spherical equivalent (SE) were assessed. Two-way ANOVA and multivariate logistic regression were employed to identify drivers of visual impairment and uncorrected refractive error, with screening year as a covariate. Generalized Estimating Equations (GEE) with student-level clustering were applied to account for repeated measures. Sensitivity analyses confirmed dataset robustness. RESULTS: Age was the predominant driver of VA variance (η2 = 0.1132), exceeding city-level effects fivefold. Xiamen exhibited the best refractive profile but the highest uncorrected rate (94.0% in primary school), illustrating the "Xiamen Paradox"-where affluence fosters a "visibility-over-correction" bias. Conversely, Quanzhou demonstrated a "pain-driven" model with high correction adherence despite a severe myopia burden (19.0% high myopia). Crucially, county-level SE disparities (up to 1.66 D) eclipsed inter-city gaps. The 5-7-year window marked a critical refractive shift, with myopia prevalence doubling. Among primary school records, only 22.6% of visually impaired children wore spectacles, and merely half achieved adequate correction. CONCLUSION: Economic prosperity does not automatically translate to optimal visual health. Significant "correction gaps" and intra-regional disparities necessitate a shift from uniform strategies to precision governance. Future interventions must prioritize the 5-7-year window, emphasize correction quality over mere screening volume, and tailor approaches to local socioeconomic contexts to transform economic capital into sustainable ocular health dividends effectively.