The benefits of exercise are well documented in all age groups; however, physical activity may impact children’s eyes differently than adults, new research suggests.

A team from China and Singapore found that children who exercised for 20 minutes had significantly decreased choroidal thickness for at least 30 minutes after physical activity and increased fundus vessel density after rest. In addition, myopic and emmetropic eyes showed differences in choroidal thinning and retinal vessel density fluctuation after exercise.

The study enrolled 58 eyes of 58 children between ages nine and 13, including 40 myopic eyes (mean spherical equivalent -3.27D) and 18 emmetropic eyes (mean SE 0.03D). None of the participants had ocular or systemic disease, nor were they taking any medication.

Researchers conducted OCT imaging and measured heart rate, systolic and diastolic blood pressure and IOP before and immediately after the children cycled on a stationary bike for 20 minutes. These measurements were recorded again after 30 minutes of rest.

The investigators reported significantly decreased choroidal thickness after exercise in both myopic and emmetropic eyes and throughout the 30-minute rest period following physical activity. This finding differs from those reported in adults who had stable or even increased choroidal thickness after exercise, the researchers noted.

Immediately after physical activity, retinal vessel density decreased in the deep retinal layers in myopic eyes. This result was consistent with previous studies investigating adult behavior, in which macular perfusion decreased after physical activity. Additionally, the vessel density of emmetropic eyes was higher in the superficial and deep layers after rest.

Another key finding: IOP didn’t significantly change during exercise or after the rest period, which is contrary to results of similar studies in adults that showed a reduction in IOP.

“Based on these results, we conclude that there are differences between children and adults, myopic and emmetropic eyes in the effects of exercise on fundus vessel density and choroidal thickness. Further studies should clarify the mechanisms and effects underlying these differences,” the study authors concluded in their paper.

Li S, Pan Y, Xu J, et al. Effects of physical exercise on macular vessel density and choroidal thickness in children. Sci Rep. January 21, 2021. [Epub ahead of print].