Prevalence of myopia and high myopia, and the association with education: Shanghai Child and Adolescent Large-scale Eye Study (SCALE): a cross-sectional study
Xiangui He, Padmaja Sankaridurg, Shuyu Xiong, Wayne Li, Thomas Naduvilath, Senlin Lin, Rebecca Weng, Minzhi Lv, Yingyan Ma, Lina Lu, Jingjing Wang, Rong Zhao, Serge Resnikoff, Jianfeng Zhu, Haidong Zou, Xun Xu
Abstract
OBJECTIVES: To report on: (a) overall myopia and high myopia prevalence, and (b) the impact of education on the spherical equivalent refractive error in children across Shanghai. DESIGN: Cross-sectional study. SETTING: Across all 17 districts of Shanghai. PARTICIPANTS: 910 245 children aged 4-14 years from a school-based survey conducted between 2012 and 2013. MAIN OUTCOME MEASURES: Data of children with non-cycloplegic autorefraction, visual acuity assessment and questionnaire were analysed (67%, n=6 06 476). Prevalence of myopia (≤-1.0 D) and high myopia (≤-5.0 D) was determined. We used a regression discontinuity design to determine the impact of school entry cut-off date (1 September) by comparing refractive errors at each age, for children born pre-September to post-1 September, and performed a multivariate analysis to explore risk factors associated with myopia. Data analysis was performed in 2017-2018. RESULTS: Prevalence rates of myopia and high myopia were 32.9% (95% CI: 32.8% to 33.1%) and 4.2% (95% CI: 4.1% to 4.2%), respectively. From 6 years of age onwards, children born pre-September were more myopic compared with those born post-1 September (ahead in school by 1 year, discontinuity at 6 years: -0.19 D (95% CI: -0.09 to -0.30 D); 14 years: -0.67 D (95% CI: -0.21 to -1.14 D)). CONCLUSIONS: Our findings suggest that myopia is associated with education, that is primarily focused on near-based activities. Efforts to reduce the burden should be directed to public awareness, reform of education and health systems.