To the Editor The school-based myopia prevention trial conducted by Dr He and colleagues1 supports what has been noted in observational studies2 that more time spent outdoors reduces the risk of myopia in children. However, one important issue regarding this finding has not been fully addressed by the authors.
Pan C, Liu H. School-Based Myopia Prevention Effort. JAMA. 2016;315(8):819. doi:10.1001/jama.2015.17133