This undated photo shows a girl with glasses looking at a tablet screen. (PHOTO / CHINESE UNIVERSITY OF HONG KONG)

HONG KONG – The increase in time spent indoors and gazing on screens amid the COVID-19 pandemic triggered a “myopia boom” in schoolchildren in Hong Kong, according to a recent study conducted by the Chinese University of Hong Kong (CUHK).   

Researchers from the CUHK's Department of Ophthalmology and Visual Sciences (CUHK DOVS) conducted a prospective population-based study to evaluate the impact of the pandemic on the incidence of myopia among Hong Kong schoolchildren and found a 2.5-fold increase.

Hong Kong is among cities with the highest prevalence of myopia in the world, affecting more than 40% of school children at the age of eight, according to a study by the Chinese University of Hong Kong

“The concern over a myopia boom in children during COVID-19 hits particularly close to home, as Hong Kong is one of the world’s most densely populated cities, with the overwhelming majority of the population living in urban areas, where outdoor spaces are hard to come by,” said Professor Clement Tham Chee-yung, chairman of CUHK DOVS.

Hong Kong is among cities with the highest prevalence of myopia in the world, affecting more than 40 percent of school children at the age of eight, according to the study.

The research team recruited 709 children (COVID-19 cohort) between December 2019 and January 2020, when school closures and restrictions on social activities were in place due to COVID-19, and followed their myopia progression for at least eight months until August 2020. 

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The control group (pre-COVID-19 cohort) consisted of 1,084 children that had been followed up for three years before the major COVID-19 outbreak in Hong Kong in January 2020. The team carried out eye examinations for the children and asked about the amount of time they spent outdoors, on screens and doing near work.

Children spent an average of seven hours on screens but only 24 minutes outdoors per day during the pandemic, according to the study.

On the contrary, kids in the control group on average spent 2.5 hours on screens and 75 minutes outdoors per day before COVID-19, according to the study.

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The researchers recommended that children spend at least two hours per day, or 14 hours per week, in the outdoors as sun exposure helps to slow down eye growth.

Myopia is the most common ocular disease worldwide and is responsible for multiple ocular complications which carry a high risk of irreversible vision loss later in life due to excessive eyeball growth in myopia. It is predicted that approximately half of the world’s population will become myopic by 2050, with the highest prevalence in East Asia.

The findings were published in the international journal British Journal of Ophthalmology.