Researchers believe that children who spend more time indoors or on screens due to Covid restrictions could have a higher rate of shortsightedness.This study looked at children aged 6-8 in Hong Kong. It is the latest to show that lockdowns and other restrictions have had an impact on vision. Data from over 120,000 children in China published earlier this year suggested a threefold rise in shortsightedness or myopia in 2020.The study's co-author, Dr Jason Yam from the Chinese University of Hong Kong, stated that near work, such as reading, writing, or watching TV, is thought to increase myopia risk. However, increased outdoor time has been shown to play a protective role.Many were kept indoors by Covid restrictions. Yam stated that schools in Hong Kong were closed for several months and that recreational facilities like playgrounds, sports fields, outdoor campsites, country parks, and other recreational facilities were also closed.Many families were forced to live in cramped spaces and limited outdoor space, so they had to choose between staying home or going indoors. He also said that more time was spent reading, watching TV, and using computers, smartphones, and other digital devices.Yam and his colleagues wrote in the British Journal of Ophthalmology about how they recruited schoolchildren from one group in 2015 and another between the 1st of December 2019 and the 24th of January 2020 when the pandemic started. The first group was followed-up after three years and the second after eight months.The team also conducted eye exams on children. They asked them questions about their time outside, screen time, and other activities.These results were based on 709 children in Covid-era and 1,084 children in pre-Covid era groups. About one third of these children developed myopia in the past three years. This compares to about one fifth in the Covid era group who had it for eight months.The team did however find that the Covid-era cohort had an average annual myopia incidence of nearly 30%, compared to just under 12% for the pre-Covid group. This suggests that there was a 2.5-fold increase during the pandemic.Also, the study revealed that outdoor time decreased dramatically between recruitment and follow up of the Covid-era cohort. It fell from 75 minutes per day to 24 after Covid restrictions had been implemented. The children's near-work time, including screen use, increased from less than 3.5 hours per day to around 8 hours per day.Yam said that while it may sound like an innocuous condition, our study found that myopia is linked to a faster progression in shortsightedness. Yam also stated that screen time was associated with increased risk of vision loss in the future.It is unclear whether these results would be applicable to children in the UK. Myopia levels are particularly high in East Asian industrialized areas. Yam stated that the UK's nationwide stay-at home mandates and possible increases in screen or near-work time could mean they might be similar.James Wolffsohn (a professor of optometry at Aston University), said that nine studies had so far identified a rise in myopia progression in the pandemic. One study suggested that this could have been partially reversed by lockdown.Wolffsohn stated that the Hong Kong study was not without its limitations. He pointed out that it was difficult to compare the groups due to different follow-up periods. It is also known that myopia progression decreases with age. He said, however, that the evidence was strong when viewed in conjunction with other papers.
