Chinese University researchers on Wednesday said they have found a worrying increase in the rates of short-sightedness among Hong Kong children, with the Covid pandemic believed to be partly to blame.

The university’s medicine department said it conducted a study between 2015 and 2021 involving 20,527 children aged six to eight.

While 25 percent of the children were found to be short-sighted in 2015, this fell to just over 23 percent between 2016 and 2019, before jumping to a record high 36 percent by 2021.

The researchers put the increase down to children spending less time outdoors during the pandemic, along with more time spent using electronic devices.

Ophthalmology and visual science associate professor Jason Yam said it is especially alarming that 25 percent of six-year-olds were short-sighted in 2021, more than double the 12 percent rate recorded in 2015.

“Twelve percent was already the top of the world. But now it’s 25 percent. So 25 percent is a significant, very very high percentage in six-year-old children,” he said.

Yam said the earlier children become short-sighted, the higher the risk they have of developing more serious eye problems in the future.

The researchers said children should spend at least two hours outdoors each day, reduce time spent looking at screens, and limit reading to no more than 30 minutes in one go.