Increase in childhood short-sightedness may be linked to pandemic

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A rise in cases of myopia or short-sightedness among children may be linked to a significant decrease in the time they have been able to spend outdoors and a sharp rise in screen time during the novel coronavirus (COVID019) pandemic, according to new research published in the British Journal of

To find out if enforced behavioral and lifestyle changes during the pandemic might have affected children’s vision, the researchers studied the eyes of 1,793 children, all of whom were part of the Hong Kong Children Eye Study (HKCES). This is an ongoing population-based study of eye conditions among 6-8 year old children.

For the study, 709 of the children were recruited to the study at the start of the pandemic in December 2019 to January 2020 and were monitored for around eight months. According to the study, 1,084 children had entered the study before the start of the pandemic and had been monitored for around three years. The children’s visual acuity or ability to see clearly was measured and they filled in questionnaires on their lifestyle, including how much time they spent outdoors and on close work, at study entry and during subsequent clinic visits.

Around one in five (19.5 percent) of the children in the COVID-19 group developed short-sightedness between January and August 2020, compared with around one in three (37 percent) of those in the pre-COVID-19 group over a period of three years. After factoring in age, gender, length of monitoring period, parental short-sightedness, and how much time was spent outdoors and on close work, the numbers of new cases of short-sightedness were higher among children in the COVID-19 group.

The estimated one-year incidence of short-sightedness was 28 percent, 27 percent, and 26 percent, respectively, for 6-, 7- and 8-year-olds in the COVID-19 group, compared with 17 percent, 16 percent, and 15 percent, respectively, for 6-, 7-, and 8-year-olds in the pre-COVID-19 group, the study said. These changes coincided with a reduction in the time the children spent outdoors, from around an hour and 15 minutes to around 24 minutes per day and an increase in screen time from around 2.5 hours/day to around seven hours per day.

The researchers also compared the current COVID-19 group with the findings of their previous study, which looked at the development of short-sightedness in children of the same ages in Hong Kong. In the previous study, 13 percent of the children developed the condition over a period of one year. This compares with 19.5 percent of the COVID-19 group in the current study over a shorter period of eight months, lending further weight to a link between the pandemic and a heightened risk of short-sightedness, suggest the researchers.

This is an observational study, and as such, can’t establish cause. Additionally, the research included questionnaire data, which rely on recall. The researchers said the findings might not reflect the impact of COVID-19 in other parts of the world, where social distancing, quarantine, and school closure policies may be different, caution the researchers. Nevertheless, they write: “despite all these insurmountable study limitations, our initial results still show an alarming myopia progression that warrants appropriate remedial action.”

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