[The relationship between classroom environment and myopia]

Objective: Based on a cohort and intervention study of the Eastern Chinese Student Surveillance, Cohort and Intervention Study (ES-SCI), this research aims to explore the correlation between monitor of the school environment and longitudinal data on myopia and provide evidence for the government myopia intervention strategy. Methods: This survey adopts the stratified cluster sampling method with the school as the unit. Students from grade 1 to grade 3 were selected according to the whole class to monitor the school environment in the classroom. Students will use the full-automatic computer optometer (TOPCON RM800) to conduct optometry from 2019 to 2021 under the condition of mydriasis to perform refractive eye examinations. Meantime eye axis length monitoring was also conducted. Cox proportional risk regression model was used to explore the relationship between school environmental monitoring and the occurrence and development of students' myopia. Results: From 2019 to 2021, 2 670 students from 77 classrooms participated in the observation study. The students' diopter after right/left eye mydriasis decreased in varying degrees (P<0.001), and the axial length of the right/left eye increased in various degrees (P<0.001). The weighted qualified rate of per capita area of primary school classrooms increased from 18.0% in 2019 to 26.0% in 2021, the weighted average illuminance pass rate of blackboard surface increased from 23.8% in 2019 to 26.4% in 2021, and the weighted average illuminance pass rate of classroom table decreased from 86.7% in 2019 to 77.5% in 2021. The trend chi-square test was significant (P<0.05). Cox proportional risk regression showed that after correcting for the grade, gender, parental myopia, diet, sleep, near work (sitting posture, working time, electronic mobile equipment, eye exercises), and outdoor activities, the per capita area of 1.36- m² was the protective factor of eye axis length (HR=0.778, 95%CI: 0.659-0.918, P=0.003); The average reflection ratio of blackboard 0.15-0.19 was the protective factor of eye axis length (HR=0.685, 95%CI: 0.592-0.793, P<0.001); The average illumination of the blackboard 150-, 300-, 500- lx was the protective factor of the eye axis length (HR=0.456, 95%CI: 0.534-0.761, P<0.001; HR=0.794, 95%CI: 0.705-0.895, P<0.001; HR=0.690, 95%CI: 0.619-0.768, P<0.001). The blackboard evenness 0.40-0.59 was the risk factor of eye axis length (HR=1.528, 95%CI: 1.018-2.293, P=0.041), and the blackboard evenness 0.80- was the protection factor of eye axis length (HR=0.542, 95%CI: 0.404-0.726, P<0.001). The evenness of the desktop 0.40-0.59 was the protective factor of eye axis length (HR=0.820, 95%CI: 0.698-0.965, P=0.017). The average illuminance of 150-, 300-, 500- lx was the protective factor of a diopter (HR=0.638, 95%CI: 0.534-0.761, P<0.001; HR=0.911, 95%CI: 0.848-0.978, P=0.011; HR=0.750, 95%CI: 0.702-0.801, P<0.001). The average illumination of desktop 500- lx was a protective factor of a diopter (HR=0.855, 95%CI: 0.763-0.958, P=0.007). Conclusion: School environmental monitoring indicators, such as meeting per capita area standards, passing blackboard, and desk top-related indicators, all play protective effects on myopia development in students.