Hansen MH, Laigaard PP, Olsen EM, et al. - Researchers identified the prevalence of myopia [defined as non-cycloplegic subjective spherical equivalent refraction ≤−0.50 D in right eye] in a Danish cohort aged 16 to 17 years and its relationship to physical activity and the use of electronic screen-based devices. Using questionnaires, information about use of screen devices and physical activity was obtained. The study sample consisted of 1,443 participants with a median age (± IQR) of 16.6 years (± 0.3). According to this Copenhagen Child Cohort 2000 Eye Study, lower physical activity and more use of screen devices in this cohort of healthy 16–17-year olds contributed significantly to the observed 25% prevalence of myopia with an approximately doubled risk of having myopia if physically active <3 hr/week or if using screen devices > 6 hr/day. The physical activity as a protective factor and near work as a risk factor for myopia in adolescents was supported.