Physical activity in relation to development and progression of myopia – a systematic review

Abstract

On a global scale, myopia is one of the most common causes of visual impairment. Given the increasing prevalence of myopia, it is vital to understand the pathogenesis and to identify potential interventions. Some studies have described physical activity as a potential correlation for myopia. The objective of this study was to make a systematic review regarding the correlation between physical activity and myopia. A total of 263 papers were identified in a systematic database search of PubMed/Medline and Embase. Five steps of screening removed studies of a low evidence quality and animal studies. Studies included had refractive error and physical activity (as measured by questionnaires, accelerometers and cycle ergometers) as separate, well-defined outcomes. Nine studies (six cross-sectional, two cohorts and one case-control study) with a total of 17 634 subjects were included. Six studies demonstrated a reverse association between physical activity and myopia. Three studies supported this, but also attributed the results to time spent outdoors and not physical activity per se. One cross-sectional study found no relation. We could not identify trends among the papers regarding the type of studies, population sizes, ethnicity or age of study subjects. A consistent relationship between more physical activity and less myopia was observed. No evidence of physical activity as an independent risk factor for myopia was seen. Evidence suggests that time outdoors remain the most important factor. Future studies should include objective measurements of physical activity to determine a potential independent effect. Distinction between physical activity and outdoor exposure remains important.

Physical activity and myopia in Danish children—The CHAMPS Eye Study

“…Our findings corresponded with previous studies, although there are some conflicting results in the literature (Suhr Thykjær et al. ). The protective role of lifestyle choices, such as PA and time outdoors, has been an area of interest in the last 10 years (Jacobsen et al.…”

“…In a systematic review investigating PA and myopia, Suhr Thykjær et al. () found a consistent relationship between more PA and less myopia. They concluded that there was no evidence for an independent effect of PA.…”

“…; Suhr Thykjær et al. ). We believe as evidence suggests that time outdoors remain the most important factor (Xiong et al.…”

“…The validity of questionnaires is, however, questionable when using subjective reports (Suhr Thykjær et al. ). Objective measurements with accelerometers offer a distinct advantage over self‐reporting methods, as they provide reliable information with real‐time data on PA pattern over a given period.…”

Choroidal thickness and myopia in relation to physical activity – theCHAMPSEye Study

“…; Suhr Thykjaer et al. ). Theories of the underlying physiological mechanisms include impact on the emmetropization due to changes in choroidal blood flow (Nickla & Wallman ; Summers ) and light‐sensitive dopamine levels (McCarthy et al.…”