This new systematic review and meta-analysis has evaluated use of smartphones and tablets separately to computer use and other non-screen based near work. Results are still mixed but overall there was a trend for a slightly increased risk with mobile device use alone, which increased when combined with computer use. More objective measures of screen time are needed to further explore this link.
A vision-screening program was able to provide data before and after Chinese schoolchildren were confined to home learning during the COVID-19 pandemic. Overall, more hours were spent indoors and less time was spent outdoors during this time, across all age groups. The younger schoolchildren had increased incidence of myopia and faster progression, whereas an increase in the prevalence of high myopia was found in the older children.
Children aged 6 to 8 years old in China were found to experience a mean -0.30D myopic shift and a significant increase in myopia prevalence during a 5-month long COVID-19 home confinement period. Due to their age and corresponding critical stage in visual development, the change in the children’s environment and lifestyle may have been more responsible for their increased myopia than the increased online learning.
Young adults wearing the spectacle-mounted Clouclip device to measure viewing behaviour and light exposure also kept an activity diary. Mean daily near work and outdoor time were subjectively reported at about 150% of the objectively measured hours. This indicates the value of objective measures in research, as well as for clinical education and behaviour modification tools in future.
A country-wide intervention to increase outdoor time in 5-6 year olds resulted in the prevalence of myopia decreasing from 15% in the 2014 cohort (before the intervention) to 8% in 2016 cohort (exposed to the intervention for up to two years) and was stable for three years thereafter. Increasing outdoor time works!
There is general widespread accepted belief that increasing time spent outdoors can be protective against progression of myopia. Xiong et al set out to better understand the research by performing a meta-analysis of 51 clinical trials and longitudinal studies that investigated the relationship between time spent outdoors and the risk of either developing myopia, progression of existing myopia or a myopic shift in refractive error.