Increasing children's time spent outdoors reduces the incidence of myopia

Commentary This well-conducted trial presents a timely next step in the investigation of time outdoors, supporting positive results from smaller trials. 3 4 However, the impact of the intervention on myopia development, although significant, is smaller than anticipated given the strong results from longitudinal epidemiological studies. 5 6 This effect size may be due to the modest increase in outdoor time (40 min/day). While the current result remains valid and any delay in onset may prevent progression to high myopia, this study highlights the need for further trials to determine optimal duration of the intervention, and whether time outdoors can reduce progression of myopia once present, which will be essential for clinical recommendations.