Scientists say myopia is sweeping across Asia, with numerous schoolchildren suffering from it. Myopia has long been thought to be primarily a genetic problem, but researchers led by Ian Morgan of the Australian National University have found that the environment is a major cause of myopia. Researchers led by Ian Morgan of the Australian National University have found that it is the environment that is a major cause of myopia: myopia is likely caused by students spending too much time studying indoors and too little time outdoors in the sun. Writing in The Lancet, the leading international journal of clinical medicine, they say that up to 90% of young people in major East Asian countries such as China, Japan, Singapore and South Korea are nearsighted. By comparison, the UK has between about 20 and 30 percent of nearsighted people. In Singapore, the proportion of nearsighted people of three different races – Chinese, Indian and Malaysian – has risen since 1996. Morgan points out that because these three different races are all affected in the same way, prevailing environmental factors are likely to be the root cause of this outcome. Today, the population of East Asian countries is spread all over the world. Studies of these people have shown that young Chinese people who are more likely to be exposed to bright daylight and live in Australia have lower rates of myopia than young Chinese living in East and Southeast Asian cities. Similarly, white children living in Sydney had lower rates of myopia than white children living in the UK. Particularly noteworthy is the fact that about 10 to 20 percent of Asian schoolchildren suffer from high levels of myopia, a condition that significantly increases their risk of developing more serious vision problems such as adult-onset blindness. The culprit for this outcome, Morgan says, is the immense pressure Asian children are under from their schools. Under pressure from schools, children have to spend much of their time indoors concentrating on their studies, leaving them with too little exposure to natural light. The study, by the Australian National University, shows that East Asian countries with high rates of myopia dominate international rankings of educational attainment. Myopia occurs when the elongation of the eyeball causes light not to be directed at the retina. A myopic person can only see an object clearly if he or she is close to it. Instead of falling on the retina at the back of the eye, the light coming into the eye concentrates on a spot in front of the retina, resulting in a blurred image of distant objects. Studies conducted on animals have shown that myopia develops in the early stages of development when the eyeballs cannot be adjusted to the proper length. These scientists believe that the neurotransmitter dopamine may play an important role in the development of eye tissue. When a person is exposed to daylight, the amount of dopamine in the eye increases, which would prevent the eye from elongating. We think we’ve found a well-documented mechanism,” Morgan said. We think that bright daylight outdoors stimulates the release of the retinal neurotransmitter dopamine, and the eye grows too large. Dopamine is known to inhibit axial growth of the eye, which is precisely the structural basis of myopia.” These researchers note that animal experiments on rats and monkeys support this conclusion. When proper eye development ends for humans is still unknown, but Morgan noted that it is worrisome that high rates of myopia appear early in East Asian countries, where elementary school children often suffer from the condition. In East Asian countries, academic stress is a major reason why elementary school children are vulnerable to myopia, and they spend too little time outdoors,” Morgan said. One of the worst problems they face from the start is that they become highly myopic over time because the eyeballs continue to elongate and they are put at high risk of developing more serious vision problems.” Are there ways to prevent myopia or stop it from getting worse? To date, there is no effective way to prevent or treat myopia other than vision-correcting lenses. The drug atropine slows eye growth, but these drops have side effects. Over time, the drug loses its effectiveness,” Morgan said. We need to find more evidence through trials to discover practical treatments for myopia.” Based on their findings, these researchers suggest that parents who allow their children who study hard to take regular breaks and are exposed to daylight for several hours a day are likely to help prevent myopia.