To the Editor In their study on 6-year-old primary school children, Dr He and colleagues1 evaluated the effect of adding 40 extra minutes of outdoor activities to each school day on the 3-year cumulative incidence of myopia. The results showed that the cumulative incidence of myopia was 30.4% in the intervention group and 39.5% in the control group (P < .001).
Nowroozzadeh MH. School-Based Myopia Prevention Effort. JAMA. 2016;315(8):819-820. doi:10.1001/jama.2015.17139