Researchers may have found the answer that could keep glasses off one-third of the world’s population

 

Nearsightedness — or myopia – is reaching epidemic portions. People with myopia or nearsightedness have difficulty seeing distant objects, but can clearly see objects that are near.

People who are nearsighted have what is called a refractive error. In nearsighted people, the eyeball is too long or the cornea has too much curvature, so the light entering the eye is not focused correctly. Images focus in front of the retina, the light-sensitive part of the eye, rather than directly on the retina, causing blurred vision.

In the US, over 40 percent of the population needs glasses; estimates suggest that one-third of the world’s population will be nearsighted by the end of the decade. The condition’s sheer pervasiveness has made researchers wonder about its cause. Now, scientists think they have a good understanding of why the condition has become more common: young people are spending too much time indoors, according to a report published in Nature.

Studies among twins showed researches that DNA influences nearsightedness, but it looks like genes aren’t the whole story. Myopia has always been related with long hours of studying and new researches are finding more and more connections that support this fact; the rise in myopia syncs up with a stronger emphasis on education. For example: In China, almost 90 percent of teenagers and young adults are nearsighted and it’s no coincidence that the average 15-year-old in Shanghai spends 14 hours per week doing homework. Last year, German researchers found that students who attended more years in school had a much higher rate of myopia than did their less academic peers.

There is still not any exact way on how to slow the rising tide of myopia, but one Australian researcher found that kids could maintain healthy vision by spending three hours per day in light of 10,000 lux or more. Many researchers agree that kids who spend more time outside will maintain good vision for much longer.

References: http://www.popsci.com/why-are-so-many-people-nearsighted

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