Interventions to increase time spent outdoors for preventing incidence and progression of myopia in children

Myopia or nearsightedness is a type of refractive error. It causes people to see near objects clearly but distant objects as blurred. Good vision can be obtained if the refractive error is corrected properly but, where this is not possible, impaired vision will remain. The remaining myopia imposes a considerable personal and societal burden. In addition, the progression of myopia is more likely to be accompanied by other ocular diseases such as cataract, glaucoma and retinal detachment. Myopia has emerged as a significant global public health problem in recent years. The World Health Organization (WHO) reported uncorrected or undercorrected myopia to be a major cause of visual impairment worldwide. From both an individual and social perspective, it is important to prevent the onset of myopia and slow down its progression. Observational studies have shown that children who spend more time outdoors have a lower incidence of myopia. Several other non-Cochrane systematic reviews have focused on the association between increasing children's outdoor activity time and the prevention of myopia. However, none of these systematic reviews were limited to randomised controlled trials (RCTs), as they included all types of study designs, including observational studies and non-RCTs, in addition to RCTs.