Hong Kong ( CNN ) It 's not just Asia . Around the world , we 're becoming collectively more near-sighted . Near-sightedness , or myopia , means nearby objects appear clearly , but those farther away look blurry . The rates of myopia have doubled , even tripled , in most of East Asia over the last 40 years , researchers say . Several places like Hong Kong , Singapore and Taiwan have rates in the 80 % . In South Korea , myopia rates among 20-year-olds have leaped from 18 % in 1955 to over 96 % myopia in 2011 . And it 's a global issue -- rates of myopia are also rising in Western nations like Germany and the United States . `` It 's about 40 % in the U.S. , compared to about 25 % in the 1970s , '' said Dr. Michael Chiang , clinical spokesperson for the American Academy of Ophthalmology . But researchers say reducing risk of myopia is easy , free and readily-available : Get some sunlight . Sometimes , though , the easiest solutions are the hardest to implement . The epidemic of myopia amongst East Asians has triggered cultural questions about why so many young people develop vision problems . Many have long believed that reading , studying or staring at your phone caused short-sightedness . And there 's the usual grumblings that young people spend way too much time glued to their screens . But researchers are focusing on a different cause . `` If children get outside enough , it does n't matter how much they study they do . They do n't become myopic , '' said Ian Morgan , researcher at Australian National University . Researchers say kids and teens need to get sunlight during the critical years of their development while their eyeballs are still growing . The mechanics of how sunlight protects their eyes are not clearly understood . One theory suggests that sunlight triggers the release of dopamine in the retina ; another speculates that blue light from the sun protects from the condition . The solution is simple . Have kids `` spend more time outside , have less demands ( from ) the schools and relax a bit , '' said Seang Mei Saw , professor of epidemiology at the National University of Singapore . But studying and play time are often at odds with each other . In Asian cultures where there is heavy emphasis on education and hyper-competitiveness , forcing playtime is easier said than done . `` The problem is teachers and parents are probably not going to let kids , '' said Dr. Nathan Congdon , professor at the Zhongshan Ophthalmic Center at the Sun Yat Sen University in China . `` There 's a limit to how many hours kids can go outside . '' There have been some attempts to protect children 's eyesight . In China , students have been mandated by its education ministry to perform daily eye exercises . Since 1963 , rows of students sit at their desks and massage the pressure points around their eyes as a revolutionary-era anthem blares through the PA system . Despite these eye exercises , rates of myopia in urban China have soared to nearly 90 % , according to recent studies . `` China has among the highest rates of myopia and it 's the only country in the world that does eye exercises , so it 's probably not working all that well , '' said Congdon . Their effectiveness has been doubted by experts in China , but the exercises remain a part of the students ' daily experience . Myopia may seem like a minor inconvenience . People have to deal with glasses , contact lenses and even laser eye surgery . But researchers say there are serious implications of such high rates of myopia among young people . In Singapore , 82 % of 20-year-olds are myopic . By the time these young adults hit their 60s , many of their vision problems are likely to get worse . `` They grow older and the epidemic is then in older adults , '' said Saw , head of the myopia unit at the Singapore Eye Research Institute . As people age , they can become at higher risk for severe eye disorders such as high myopia , glaucoma ( optic nerve damage ) , cataracts ( clouding of the lens ) and retinal detachment . These conditions could lead to vision loss and blindness . To negotiate the expectations of parents and classes , researchers are experimenting ways to help students get increased exposure to sunlight . One of the studies underway is the `` bright light classroom '' where the school 's walls and ceilings are made of see-through plastic that allows in light . Hundreds of students attend this unusual elementary school in Guangdong province . `` It 's a potential way to increase the amount of light , in hopes of preventing myopia and allow kids to continue ( their ) education without inconvenience for them , '' Morgan said . Researchers want to measure the rates of myopia among students in these `` bright light classrooms '' compared with those in traditional classes . Building schools costs money -- especially experimental see-through schools . But researchers say there are low-cost solutions . In one Taiwanese study , teachers locked the students out of the classroom during recess and lunch time . In that 2013 study , students boosted their time in sunlight by 80 minutes during the school day . Fewer children in that school became nearsighted compared with those from another school that did n't follow such a policy . Researchers hope with greater understanding of this condition , far-sighted policies could save the next generation of children 's eyesight .
East Asia sees soaring rates of myopia , with 18 % of young adult population affected . Evidence that myopia rates are increasing in Europe and the U.S. Scientists advice for kids : Go outside and play .