Getting myopia at a young age can set you up for worse myopia later in life, a study by the Singapore Eye Research Institute has found.
This means that parents should try their best to delay myopia in their children by making sure they spend time outdoors, said Professor Saw Seang Mei, who headed the study.
"We know that if you spend more time outdoors as a young child, you can prevent or delay myopia," said Prof Saw, who heads the myopia research group at the institute. She was speaking at a media briefing yesterday on the study's findings.
Good eye habits
• Keep any reading material at least 30cm away from your eyes and try to read in an upright position instead of lying down.
• Keep computer screens at least 50cm away from your eyes, and adjust them to minimise glare.
• Make sure the television screen is at least 2m away.
• Take a break from reading, watching television or using the computer every 30 to 40 minutes. Look out of the window at faraway objects and do eye exercises to relax the eyes.
• Engage in more outdoor activities and make sure indoor activities take place with sufficient light.
Doctors hypothesise that this could be because light outdoors is usually much brighter, triggering the release of a chemical known as retinal dopamine, which stops myopia from developing.
Prof Saw and her team recruited nearly 1,000 children aged between seven and nine over several years for the study, and followed up with them until they reached age 11.
Those who were first diagnosed with myopia when they were very young - between three and six years old - ended up with high myopia of more than 500 degrees, on average, by the time they were 11.
On the other hand, those who started having the condition at age 10, when the condition had only a year to progress, had myopia of about 150 degrees on average.
"Once you have myopia, you are always myopic," said Prof Saw, who is also an epidemiology professor with the Saw Swee Hock School of Public Health at the National University of Singapore.
"The younger the child who has myopia, the higher the chance of his final degree of myopia being high, because the duration of progression is longer."
Myopia tends to stabilise when a person reaches adulthood, said Prof Saw, meaning that those who have high myopia at age 11 would likely see the condition worsen as they grow up.
Singapore has one of the highest rates of myopia in the world - approximately seven in 10 teenagers have the condition.
The children in the study were part of a larger project called the Singapore Cohort Study of the Risk Factors for Myopia, which involved nearly 2,000 children. Some of them, who are in their 20s by now, are still being followed up to this day to find out how their conditions have developed.
In an earlier study, Prof Saw and her team also found that having high myopia of more than 500 degrees puts adults at risk of issues such as cataracts, glaucoma and myopic macular disease - a degenerative disease that causes loss of vision - down the road. This makes prevention at a young age even more important.
For Mr Htoo Yan Kyaw, a 29-year- old sales manager, keeping his son's eyesight perfect is about limiting screen time and taking the 2 1/2- year-old outside to play as often as he can. "Nowadays, kids like to use iPads and (other gadgets) to watch videos, but of course you have to train them not to do that so often."