Progression of myopia among school-aged children in Guangzhou, China.

Aim: To investigate the prevalence and characteristics of myopia in school-aged students and effects of environmental and genetic factors on the progression of myopia.

Methods: A total of 2422 students aged between 5 and 18y from nine schools in Baiyun District of Guangzhou, China were sampled using a stratified sampling method in 2020. Among them, 1066 students participated in the follow-up survey the following year. Data were obtained based on ocular examinations and a questionnaire survey conducted during two visits. Factors potentially influencing the progression of myopia were analyzed.

Results: During the year assessed in this study, the percentage of students with myopia increased from 58.4% to 64.8% (P=0.002). Spherical equivalent (SE) progressed from -1.44±1.91 diopters (D) at baseline to -1.66±1.10 D (P=0.005). A generalized estimating equation (GEE) model revealed that age [adjusted odds ratio (aOR)=1.298, P<0.001], residential students (aOR=2.428, P=0.018), parental myopia (one myopic parent: aOR=1.553, both parents myopic: aOR=2.609, P<0.001), frequent reading of books or viewing of screens in direct sunlight (aOR=3.502, P=0.023), using only overhead lighting for reading and writing at night (aOR=1.633, P=0.011), parental restrictions on exercise time (aOR=2.286, P=0.012), and having less than 2h of outdoor exercise per day during the past week (aOR=1.584, P=0.019) were all identified as independent risk factors for progression of myopia.

Conclusion: Our findings in this study indicate that age, residential students, parental myopia, indoor lighting environment, and physical activity have significant effects on the progression of myopia, providing evidence for further in-depth mechanistic interpretation and efficient intervention strategies for school-age children in this area.