A rise in the number of short-sighted children may be linked to increased screen time during the pandemic, a study suggests.
During lockdown, children in general spent less time outdoors and more time inside watching TV or on a computer.
And this may have prompted a rise in cases of short-sightedness, or myopia, according to research.
Scientists studied the eyes of 1,793 children in Hong Kong. Around 700 of the children were recruited to the study at the start of the pandemic, while the rest had already been monitored for around three years.
Their ability to see was measured and they filled in questionnaires on their lifestyle, including how much time they spent outdoors and looking at screens.
During lockdown, children in general spent less time outdoors and more time inside watching TV or on a computer. And this may have prompted a rise in cases of short-sightedness, or myopia, according to research
Around one in five children in the Covid group developed short-sightedness between January and August 2020, compared with one in three of those in the pre-Covid group over much longer period of three years.
The estimated one-year frequency of short-sightedness was 28 per cent, 27 per cent and 26 per cent respectively for six, seven and eight-year-olds in the Covid group.
This compared with 17 per cent, 16 per cent and 15 per cent respectively for six, seven and eight-year-olds in the pre-Covid group.
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 to around 7 hours per day.
Lead author Dr Jason Yam said: ‘Our initial results show an alarming myopia progression that warrants appropriate remedial action.
‘They serve to warn eye care professionals, 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.
‘Short-sightedness in children matters. It puts them at risk of developing complications that increase the risk of irreversible impaired eyesight or blindness later in life.’
The data, collated from the Hong Kong Children Eye Study, was published in the British Journal of Ophthalmology.
Hong Kong is one of the most densely populated cities in the world with residents living in high-rises with little outdoor space.
Commenting on the study Oliver Braddick, emeritus professor of psychology at the University of Oxford, said: ‘The Covid pandemic provided an interesting opportunity to examine whether the imposed changes in lifestyle changed the development of eyesight in primary-age children.
‘It’s unfortunate, however that this study could not make the most direct comparison between development of myopia in the pre-Covid and Covid-period cohorts, since the two groups were followed up over different intervals of time.
‘However, there is other evidence from a study in Sydney in 2013 that outdoor activity in daylight has a protective effect against children developing short-sightedness, which is consistent with the findings of this study.
‘It should be noted that this study was carried out in an urbanised East Asian population, among whom myopia levels are generally higher than in groups of European ancestry.’
Earlier this year a survey found almost four-in-ten Britons believe their eyesight has worsened during the pandemic.
Eye health charity Fight for Sight advises people to learn the ‘20-20-20’ rule – looking at something 20 feet away for 20 seconds every 20 minutes you look at a screen.
THE DIFFERENCE BETWEEN SHORT AND LONG -SIGHTEDNESS?
Both short-sightedness and long-sightedness are common conditions which diminish a person’s eyesight.
Short-sighted people (myopic) have difficulty seeing objects at a distance.
They favour objects that are closer to them.
Their vision is clear when looking at things up close, but further away objects become out of focus or blurred.
Short-sightedness (myopia) occurs when the distance from the front to the back of the cornea’s curve is too steep.
This forces the light to focus in front of the retina, making objects in the distance appear blurred.
Long-sightedness (hyperopia) is the opposite of this and allows people to see objects clearly at a distance but find it hard to focus on things close to them.
This makes day-to-day activities such as working, reading or watching TV difficult and can result in eye strain. This then produces fatigue and headaches.
Long-sightedness occurs when the distance from the front to the back of the cornea’s curve is too steep.