Investigators Identify Childhood Myopia as Potential Crisis During COVID-19

Childhood myopia, or nearsightedness, is a potential public health crisis due to its increase during the COVID-19 pandemic, according to authors of a study.

In the article published in the British Journal of Ophthalmology, researchers at the Chinese University of Hong Kong found a potential increase in myopia incidence, a significant decrease in outdoor time, and an increase in screen time among schoolchildren in Hong Kong during the pandemic.

They conducted analyses of 2 separate longitudinal cohorts of children aged 6 to 8 years. The COVID-19 cohort was recruited at the beginning of the COVID-19 outbreak and the pre–COVID-19 cohort was recruited before the pandemic.

All children received eye exams and answered a standardized questionnaire relating to their lifestyle, including time spent on outdoor activities and near work (ie, activities done at a close distance), both at baseline and at follow-up visits.

They recruited 1793 children, including 709 children in the COVID-19 cohort with a mean (SD) of 7.89 (2.30) months of follow-up and 1084 children in the pre–COVID-19 cohort with a mean (SD) of 37.54 (3.12) months of follow-up.

The time spent on outdoor activities declined from a mean (SD) of 1.27 (1.12) hours per day prepandemic to 0.41 (0.90) hours per day during the pandemic, while screen time soared from 2.45 (2.32) to 6.89 (4.42) hours per day.

The investigators also observed an increased incidence of myopia: 36.57% among the schoolchildren during the pandemic and 19.44% in the pre–COVID-19 cohort. During the pandemic, the mean (SD) changes in spherical equivalent refraction and axial length were –0.50 (0.51) D and 0.29 (0.35) mm, respectively.

“Our results serve to warn eye care professionals, and also policy makers, educators and parents, that collective efforts are needed to prevent childhood myopia—a potential public health crisis as a result of COVID-19,” they wrote.

Hong Kong’s 800,000 students were faced with a school closure in late January 2020. “This unprecedented level of quarantine has resulted in the required use of digital platforms to continue learning; it has also significantly affected the well-being of children and their families in Hong Kong,” the researchers wrote.

Because Hong Kong is one of the world’s most densely populated cities, the overwhelming majority of the population lives in urban areas in high-rises and small apartments, where outdoor spaces such as backyards, gardens, and outdoor playgrounds are hard to come by, according to the authors.

“Under these circumstances, schoolchildren are spending significantly less time outdoors and more time overall on near work,” they wrote, pointing to their findings of a 68% decrease in outdoor time coupled with a 2.8-fold increase in screen time.

“Evidence suggests that when children are out of school, they are physically less active and have much longer screen time, and of all the environmental risk factors that have been studied, increased outdoor time has been consistently shown to have a protective role against the development of myopia,” the researchers noted.

Plus, total near work and screen time during the pandemic were more than double pre–COVID-19 levels, due to schools employing digital teaching methods, they wrote.

Reference

Zhang X, Cheung SSL, Chan HN, et al. Myopia incidence and lifestyle changes among school children during the COVID-19 pandemic: a population-based prospective study. Br J Ophthalmol. Published online August 2, 2021. doi:10.1136/bjophthalmol-2021-319307