Main Outcomes and Measures
diopters
MYOPIA
The primary outcome was the between-group mean difference in mathematics test scores at the end of 1 academic year, with a noninferiority margin of −3.3 points. Standardized mathematics tests, physical fitness assessments (in reference to the 2018 National Physical Fitness Survey Monitoring Programme in China), and cycloplegic autorefraction were performed at baseline and the end of 1 academic year. Myopia was defined as a cycloplegic spherical equivalent refraction of −0.5 diopters or less in either eye.