The prevention and control of myopia have become a major public health task throughout the world. The analysis of the modifiable factors associated with myopia will help in planning concrete strategies that can be widely implemented by schools and families.PURPOSE: This study assessed the modifiable factors associated with myopia and compared them between rural and urban regions. METHODS: Data were collected from December 2020 to March 2021. A multistage stratified cluster sampling method was used to select 6154 middle school students. All children underwent an eye examination, including visual acuity and cycloplegic refraction. Data on near work, sleep, and outdoor activities were collected in questionnaires. RESULTS: The myopia prevalence values in urban and rural regions were 68.1 and 63.7%, respectively (χ 2 = 15.57, P < .001). More than 3 hours of homework per day (odds ratio [OR] in urban and rural regions, 1.36 [95% confidence interval {CI}, 1.07 to 1.75] vs. 1.72 [95% CI, 1.43 to 2.07]), 36 to 40 core subjects per week (OR, 1.30 [95% CI, 1.04 to 1.57] vs. 1.42 [95% CI, 1.24 to 1.64]), and going to sleep before 10 o'clock (OR, 0.56 [95% CI, 0.32 to 0.93] vs. 0.50 [95% CI, 0.28 to 0.90]) were significantly associated with myopia in both regions. In contrast, taking breaks during near work was a significant factor in the rural region (<1 hour: OR, 0.57 [95% CI, 0.42 to 0.76]; 1 to 2 hours: OR, 0.63 [95% CI, 0.46 to 0.86]) but not in the urban region. More time outdoors per day was associated with a reduced prevalence of myopia only for urban children (2 to 3 hours: OR, 0.55 [95% CI, 0.31 to 0.97]; >3 hours: OR, 0.38 [95% CI, 0.19 to 0.75]).CONCLUSIONS: Homework loads and the time of going to sleep were associated with myopia for children in both urban and rural regions. However, time outdoors was only associated with myopia in urban regions, and taking breaks during near work was only associated with myopia in rural regions.
