Just a few hours of play outdoors can help prevent or delay the onset of myopia in children, says Professor Saw Seang Mei, Head, Myopia Research Group, Singapore Eye Research Institute (SERI), at Singapore National Eye Centre (SNEC).
Professor Saw Seang Mei had her way, all pre- and primary school children would be sent to play outdoors for two to three hours a day. Why? Because it’s been found that sunlight can stave off myopia.
Benefits of outdoor play
Spending time outdoors also reduces children’s risk of developing high myopia (500 degrees or more) in later years, she said. High myopia in adults can lead to pathological myopia, in which the eyeball elongates (above, right), and other conditions such as myopic macular degeneration, cataract, and glaucoma, all of which can cause irreversible blindness.
Prof Saw said
bright outdoor light keeps myopia at bay by stimulating the release of dopamine in the retina, which prevents elongation of the eye. On a clear, sunny day, outdoor light levels are much higher than in a well-lit room, and a glass classroom with sunlight streaming in from all sides has been developed to test and evaluate this in Guangzhou, China.
Sun protection still important
So, she advises children, including those already with myopia, to spend some time outdoors every day. “But protect yourself by wearing sunscreen, a wide-brimmed hat and wrap-around sunglasses, and by drinking water. In Singapore it’s best to go out early in the morning or later in the evening because it’s too hot between 10am and 4pm.”
Prof Saw led the Singapore Cohort Study Of The Risk Factors For Myopia, conducted by SERI and NUS , which studied 1,979 seven- to nine-year-olds between 1999 and 2001, and tracked them until 2007.
“In the majority of studies, a person is only tested once, but we examined each person every year for eight years, and could then predict what would happen to them in the future. We looked at a wide variety of risk factors for myopia, but the most important was the amount of time a child spends outside,” said Prof Saw.
Myopia and progression rate to high myopia
The study found that 69.1 per cent of participants aged 11 to 18 had myopia; 12.6 per cent had high myopia. It also found that the best way to predict whether a child would develop high myopia is to look at when he or she first became short-sighted. “The earlier a child develops myopia, the more likely he may develop high myopia in later life, because there is more time for the myopia to progress, until about 20 to 25 years of age when the
According to the study, the mean age at which Singaporean children start having myopia is eight and a half. For every year earlier than this, the final degree increases by 100. Progression is also highest in the first three years after the onset of myopia, so the earlier treatment starts, the better.
Eye care for myopic children
Prof Saw's advice for children with myopia:
- See an eye care professional so that their progression rates can be monitored and treatment can be considered.
- Moderate time spent on near work such as reading and writing, using the computer, or playing handheld games should be moderated.
- Take frequent breaks.
- For those who developed it at an early age, the most effective way to slow the progression of myopia is atropine eye drops. But this is recommended on a case-by-case basis.
As a child grows up, myopia progresses at a slower pace, and treatment can then include special daily disposable contact lenses. There are ongoing clinical trials in many countries, including Singapore, to test their safety and efficacy.
The myopia epidemic
“In the past 20 years, rates in young people living in urban areas in Asia have risen to very high levels,” said Professor Saw. Singapore’s rates are among the highest in the world, she added. About 82 per cent of young adult males have myopia, with 15 per cent having high myopia. Contrast this with the myopia rate of 26-36 per cent and high myopia rate of 3-4 per cent in the 40-80 age bracket.
Prof Saw warns of a possible myopia epidemic in Singapore by 2050, as the current younger generation grows older and the population ages. She said that it is estimated that five million
of the country’s projected six million people will be myopic, and that 900,000 of these will have high myopia.