By Cherice Chen
Taiwan News, Staff Writer
2012-05-04 11:40 AM
The lead author of the study, Professor Ian Morgan of the Australian National University, said the problem is caused by neither genes nor the increase in activities like reading and writing, but by a simple lack of sunlight.
Exposure to the sun’s rays is believed to stimulate production of the chemical dopamine, which in turn stops the eyeball from growing elongated and distorting the focus of light entering the eye, Morgan said.
More than other groups, children in East Asia “basically go to school, they don’t go outside at school, they go home and they stay inside. They study and they watch television,” the scientist said.
“The amount of time they spend on computer games, watching television can be a contributing factor. As far as we can tell it is not harmful in itself, but if it is a substitute for getting outside, then it is,” said Morgan.
The average primary school pupil in Singapore, where up to nine in ten young adults are myopic, spent only about 30 minutes outdoors every day ― compared to three hours for children in Australia where the myopia prevalence among children of European origin is about 10 percent.
The figure in Britain was about 30 to 40 percent and in Africa “virtually none”, according to Morgan.
Of these, 10 to 20 percent had a condition called “high” myopia, which can lead to vision loss and blindness.
The generic drug atropine has been shown to slow the progression of myopia, although it causes unwanted side effects, the researchers said.
“Most of what we’ve seen in East Asia is due to the environment, it is not genetic,” said Morgan. “As long as they get outside it doesn’t seem to matter how much study they do.”
“There are some kids who study hard and get outside and play hard and they are generally fine. The ones who are at major risk are the ones who study hard and don’t get outside,” Morgan explained.
He said ways must be found to get children to spend more time in reasonably bright daylight without compromising their schooling.