Limitations
MYOPIA
This study had several limitations. First, the open-label design may bias the results. Future studies comparing a light treatment simulator with a much lower power should exclude potential placebo effects. Second, because of the outbreak of the COVID-19 pandemic in Shanghai, approximately 70% of the children in the intervention group discontinued treatment from 9 to 12 months. Nevertheless, we tried to maximize the follow-up retention rate for the 12-month visit. Furthermore, children who continued treatment and those who discontinued treatment were well balanced for baseline characteristics. Third, the observed efficacy of the intervention in preventing myopia was generalizable only to the device used in the present study. It is unproven that other wavelengths, power intensities, or frequencies of intervention may have a similar or even better efficacy.