Myopia in Children and Objectively-Measured Physical Activity

Abstract

Purpose:: The prevalence of myopia is increasing in several countries. Most research has concentrated on aetiological factors, ocular co-morbidity and treatments -there has been little information about non-ocular associations of myopia that might be important for health and well-being. We present data from an ongoing birth cohort study regarding the physical activity levels of young myopic individuals.

Methods:: Participants were children involved in the Avon Longitudinal Study of Parents and Children (ALSPAC).The children had autorefraction at 10 years and physical activity levels measured at 11 years. Physical activity was measured with an accelerometer for up to 7 days. This instrument provides a continuous objective measure of physical activity.

Results:: Using multiple linear regression and adjusting for age, gender and body mass index (BMI), children who were myopic at 10 years had lower levels of physical activity (logged mean number of minutes per day of moderate or vigorous activity) at 11 years, compared to non-myopic children: (ß = -0.156; 95% CI-0.261, -0.051; p = 0.004). Myopic children also had a higher number of minutes per day of sedentary activity: 15.7 minutes: 95% CI 5.8, 28.6; p = 0.002.

Conclusions:: Myopic children in this cohort have lower levels of objectively-measured physical activity compared to their non-myopic peers. This finding echoes previously reported indirect accounts of myopic children spending less time on outside or sporting activities than emmetropic children and it supports the recent hypothesis that outside activities may be protective against myopia. The data may also suggest that the current management of myopic refractive error puts children at increased risk for ill-health associated with sedentary living.

Keywords: myopia • clinical (human) or epidemiologic studies: risk factor assessment • refraction