Refractive Errors and Their Associated Factors in Schoolchildren: A Structural Equation Modeling

To determine the prevalence of myopia and hyperopia in Shahroud schoolchildren and their risk factors Optometric examinations including the measurement of uncorrected and corrected visual acuity as well as non-cycloplegic and cycloplegic refraction using retinoscopy were done for students. Generalized Structural Equation Modeling (GSEM) was used to determine direct and indirect effects of independent variables on myopia and hyperopia. The data of 5581 students with a mean age of 9.24 ± 1.7 years were used in this study. The prevalence of myopia was 5.0% (95%CI: 4.3–5.7) and the prevalence of hyperopia was 4.8% (95%CI: 4.0 − 5.5) in all schoolchildren. According to the GSEM results, the odds of myopia in rural areas were 0.55 compared to urban areas. A one-unit increase in the ocular AL increased the odds of myopia by 4.91 times. The interaction of sex and age on myopia was significant such that in girls, the odds of myopia increased by 20% for every one-year increase in age while no significant change was seen in boys. A one-unit increase in the ocular AL decreased the odds of hyperopia by 0.49 times. Moreover, the interaction of outdoor activity hours and sex on the prevalence of hyperopia was significant such that increased outdoor activity reduced the odds of hyperopia in girls while no significant correlation was found in boys. Myopia and hyperopia had moderate prevalence. Axial Length had the largest direct association on myopia and hyperopia. Age and outdoor activity had weak associations on refractive errors.

为明确沙赫鲁德（Shahroud）学龄儿童的近视与远视患病率及其危险因素，本研究对受试学生实施验光检查，内容涵盖裸眼视力、矫正视力检测，以及采用视网膜检影法完成的非睫状肌麻痹验光与睫状肌麻痹验光。本研究采用广义结构方程模型（Generalized Structural Equation Modeling, GSEM），解析各类自变量对近视、远视发生的直接与间接效应。本次研究共纳入5581名学生，其平均年龄为9.24±1.7岁。全体受试学龄儿童的近视患病率为5.0%（95%CI: 4.3–5.7），远视患病率为4.8%（95%CI: 4.0–5.5）。基于GSEM分析结果，农村地区儿童的近视发生比值比为城市地区的0.55倍；眼轴长度每增加1个单位，近视发生的比值比升高4.91倍。性别与年龄对近视的交互效应具有统计学意义：女童中，年龄每增长1岁，近视发生的比值比升高20%；而男童未观察到显著变化。眼轴长度每增加1个单位，远视发生的比值比降低0.49倍。此外，户外活动时长与性别对远视患病率的交互效应具有统计学意义：增加户外活动时长可降低女童的远视发生比值比，但男童未发现显著相关性。本次研究中，近视与远视的患病率处于中等水平；眼轴长度与近视、远视的直接关联强度最高；年龄与户外活动时长对屈光不正的关联强度较弱。