Last year, researchers in Taiwan found that playing outdoors reduces the onset and progression of myopia in schoolchildren. Around the same time, Global Times published a report explaining that staring at the screen of an iPad closely tightens the ciliary muscles of the eyes and will lead children to suffer from headaches. If the ciliary muscles remain tightened for a long time, they will change the shape of the eyeballs which will lead to myopia.

How the parents of one 9 year-old in Guangzhou must be rueing their failure to heed such advice when they were told their son’s myopia had increased by 200 degrees in one month because he spent most of the summer holiday playing on his iPad, Xinkuaibao reports. To get an idea of how much that is, YourHealth recommends that parents take their child for a doctor’s check-up if their myopia increases by 100-200 degrees in one year.

After Xiao Lin had his eyes tested on July 31, his father explained that every day he had to commute to Zhuhai, so he seldom had time to supervise his son during school holidays.

They are far from the only family who would have benefited from taking the advice about the dangers of iPads and the advantages of playing outside. Hu Li, an ophthalmologist at Guangzhou No.3 Hospital, said that in recent weeks, 70-80% of his patients had been children and the biggest cause of their eyesight problems were tablets and smart phones.

Hu said he was working overtime all summer, and he is not alone.

Eye doctors at Zhongshan University Hospital said they were seeing over 300 children a day.

Last year the National Bureau of Statistics revealed that China has the second highest rate of short-sightedness in the world. Up to 61% of primary school students are short-sighted, 68% of middle-school students are short-sighted, and 90% of university students are short-sighted, the paper reports.