A study found time outdoors offered limited benefit for pre-myopic children to prevent or delay myopia onset.  

Evidence of a protective effect was only present in the highest exposure group, suggesting longer duration of time outdoors or additional interventions are required to prevent or delay myopia onset in this population, wrote authors.  

Post-hoc analysis of findings from the 'Shanghai time outside to reduce myopia' (STORM) study (3,194 participants: 1,369 pre-myopic; mean age 8.2±0.6 years; 49.5% boys) found hyperopes showed reduced myopic shift with increasing outdoor time (plateauing at about 120 min/day) while for pre-myopes, a reduced myopic shift was only observed with time outdoors >120 min/d, although it was still not statistically significant (>120 min/d: 0.04, 95% CI −0.05 to 0.14), according to authors.  

The study’s findings hold significant implications for future myopia prevention efforts, the authors noted. “While the protective effects of time outdoors are clear for children with hyperopia, the protective effect of time outdoors on myopic shift among children with pre-myopia is more limited and was only seen with longer durations of time outdoors. 

“Nevertheless, in school-based interventions, given the other benefits of time outdoors, increased time outdoors should be provided for all children. However, additional interventions, such as low-dose atropine or red-light therapy, to prevent or delay myopia onset in pre-myopic children, may be useful,” they concluded.  

The paper was published in the British Journal of Ophthalmology.