Children who have been confined to indoor spaces over the course of the pandemic may be at greater risk of developing short-sightedness, according to the findings of a new study. Presenting their research in the British Journal of Ophthalmology, the authors report a rise in the condition – also known as myopia – in young children in Hong Kong during the first eight months of 2020.
Myopia is a fairly common condition that is characterized by a reduced ability to see far-away objects clearly, and occurs when the shape of the eye causes light to refract in such a way that images become focused in front of the retina, rather than directly on its surface. Environmental factors are known to play a significant role in the development of the condition, with a lack of time spent outdoors and excessive screen time being major drivers of myopia.
With the closure of schools, parks, and other recreational facilities around the world during the current pandemic, huge numbers of children have had to spend more of their time inside, resulting in an increase in what the study authors refer to as “near work”, including reading, writing and looking at screens.
To investigate the impact of this lifestyle change on the ocular health of young children, the researchers tested the eyesight of 709 children in Hong Kong at the beginning of 2020, with a follow-up examination in August of that year. Participants also filled in questionnaires regarding how much time they spent outdoors and engaging in near work.
Over the eight-month study period, 19.5 percent of children developed myopia. In contrast, the condition arose in 37 percent of a separate cohort of children that were observed over the three years preceding the pandemic. Yet when adjusting for the shorter monitoring period, the study authors found that the one-year incidence of short-sightedness was considerably higher in the kids that had been recruited during the COVID lockdown.
Specifically, they found this rate to be 28 percent, 27 percent, and 28 percent for six, seven and eight-year-olds respectively during the pandemic. Among the pre-COVID cohort, these figures stood at 17 percent, 16 percent, and 15 percent.
This dramatic increase in myopia rates over the first eight months of 2020 correlated with a massive decrease in the average amount of time children spent outdoors, which dropped from an hour and 15 minutes a day to just 24 minutes a day. At the same time, screen time shot up from an average of 2.5 hours a day to seven hours, including school time.
Overall, the researchers calculated that 29 percent of six- to eight-year-olds could expect to develop myopia during a year of lockdown. For comparison, previous studies on children from the same age group in Hong Kong revealed a one-year myopia incidence of 13 percent in the pre-COVID era.
While these findings are obviously worrying, the researchers are quick to point out that they may not be globally applicable, as restrictions have varied from country to country throughout the pandemic. Furthermore, no causal association between lockdowns and myopia has been identified, so the results of observational studies like this shouldn’t be interpreted as proof of such a link.
Having said that, it's worth bearing in mind that this is not the first study to connect myopia with COVID lockdowns. Earlier this year, for instance, a study involving over 123,000 Chinese children found 21.5 percent of six-year-olds developed myopia in 2020. Contrastingly, a one-year incidence of myopia within this age group did not exceed 5.7 percent in any of the five preceding years. Separate research conducted in the UK, meanwhile, indicated that children who spend more time indoors playing video games tend to be more likely to develop short-sightedness.
Taking all of this evidence into account, the authors of the latest study conclude that their findings "show an alarming myopia progression that warrants appropriate remedial action.”