A study in the British Journal of Ophthalmology has shown that children can reduce the risk of developing myopia by spending more time outdoors.
In a study in which 1,077 people were studied, researchers found that while genetic factors affect this equation, controlled environmental factors, such as playing video games, also affect the likelihood that the child will become short-sighted.
Those who were playing video games in early puberty were proportionately more at risk of developing myopia, which is suggested by researchers who spend less time on outdoor activities.
"It is important to have a healthy balance of time outdoors and balance during early education," said The Guardian Katie Williams, author of the study.
In addition, the researchers found children born in the summer in which there is a greater likelihood of developing myopia than their peers. The fact is that scientists attributed earlier access to the education system, which is associated with changes in the shape of the eyeball associated with myopia.
Although only a quarter of the world's population of young people was diagnosed as short-sighted in 2000, this number is expected to increase to more than half of the world's population by 2050, especially in Asia, where this number could increase by up to 90%.
So why are so many young people developing myopia?
Having short-sighted parents is a risk factor for myopia, but the cause of the current epidemic is "acquired, not genetic," according to the latest description published in Progress in retinal and eye examination.
Increasing the amount of time children and young people spend in front of screens may seem like an obvious answer. But the real explanation is probably not so simple.
Instead of the screens themselves causing eye damage, the reason may be an increasingly sedentary lifestyle for children and adolescents.
Looking at the screens of smartphones or computers is a form of "close work" – which means activities involving close-up, such as reading, watching TV or sewing – which in fact is associated with an increased risk of myopia.
However, this risk can be compensated for by spending time away from home. "There is now consistent evidence that children who spend more time outdoors are less prone to short-sightedness," the researchers write.
This theory would explain why the short-sightedness epidemic is particularly common in high-pressure cultures in an educational environment that is usually accompanied by long hours of learning and little time to play outdoors.
"In the 1950s, about 20-30% of 20-year-olds in Hong Kong, Taiwan and South Korea suffered from myopia," says Bloomberg, compared to over 80%.
This hypothesis works even for populations with low exposure to the screens – studies in Israel show that orthodox Jewish boys who spend long days reading printed religious magazines suffer a much higher rate of myopia than their secular counterparts.
Experts have calculated that two hours a day can alleviate the risk of short-sightedness associated with 'close work'. However, parents' anxiety, requiring household schedules and the development of electronic entertainment, are increasingly keeping children in homes. A study conducted in 2016 showed that 74% of children in the UK aged 5-12 spent no more than an hour a day playing outside the home – less than time spent outside for prisoners.