Friday , November 27 2020

Myopia: Why do so many need glasses?



A study in the British Journal of Ophthalmology concluded that children may reduce the risk of developing myopia by spending more time outdoors.

In a study that looked at 1,077 people, scientists have discovered that while genetics affects the equation, controlled environmental factors such as video game play also influence the likelihood of a child becoming short-sighted.

Those who played video games in early puberty were proportionally more at risk of developing myopia, which researchers suggest they are associated with spending less time on outdoor activities.

"The healthy balance of time in the countryside and the balance in initial education is important," said Katie Williams, the study's author at The Guardian.

Additionally, scientists discovered babies born in the summer who were more likely to develop short-sighted distrust than their fellow students, which the researchers believed in a previous entry into the education system, which is related to changes in the shape of the bulb is associated with myopia.

Although only a quarter of the world's population of young people diagnosed as short-sighted in 2000, the number is expected to increase to more than half of the world's population by 2050, especially in Asia, where this figure could reach 90%.

So why do many young people develop short-sighted behavior?

The presence of short-sighted parents is a risk factor for myopia, but the cause of the current epidemic is "acquired rather than genetic", according to a recent review published in Progress in retinal and ocular research.

Increasing the time that children and young people can see in the screens may seem the obvious answer. But the real explanation is probably not that simple.

Instead of the screens themselves causing damage to the eyes, it may be the ever-sedentary social life of children and young people.

Screening on monitors or on computer screens is a form of "close-up" – meaning intensive focusing activities such as reading, watching TV or sewing – which is indeed associated with an increased risk of becoming short-sighted.

However, this risk can be offset over time. "There is now consistent evidence that children who spend more time outdoors are less likely to be or become myopic," the researchers write.

This theory would explain why the myopia epidemic is particularly prevalent in cultures with a high pressure educational environment, usually accompanied by many hours of study and a little time for outdoor play.

"In the 1950s, about 20-30% of 20-year-olds in Hong Kong, Taiwan and South Korea suffered from myopia," compared to over 80% today, says Bloomberg.

This hypothesis also applies to populations with low exposure to displays – studies in Israel show that orthodox Jewish boys who spend long days over printed religious writings suffer from a much higher percentage of short-sighted than their secular counterparts.

Experts have estimated that two hours a day outside can mitigate the risk of "near work" myopia. However, parental anxiety, demanding timetables and the rise of electronic entertainment increasingly keep children indoors. A survey in 2016 found that 74% of British children aged 5-12 spent no more than an hour a day playing outside – less than the rural time given to the prisoners.


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