Massive rise in Asian eye damage

Up to 90% of school leavers in major Asian cities are suffering from myopia - short-sightedness - a study suggests.

Researchers say the "extraordinary rise" in the problem is being caused by students working very hard in school and missing out on outdoor light.

The scientists told the Lancet that up to one in five of these students could experience severe visual impairment and even blindness.

In the UK, the average level of myopia is between 20% and 30%.

According to Professor Ian Morgan, who led this study and is from the Australian National University, 20-30% was once the average among people in South East Asia as well.

"What we've done is written a review of all the evidence which suggests that something extraordinary has happened in east Asia in the last two generations," he told BBC News.


"They've gone from something like 20% myopia in the population to well over 80%, heading for 90% in young adults, and as they get adult it will just spread through the population. It certainly poses a major health problem."

Eye experts say that you are myopic if your vision is blurred beyond 2m (6.6ft). It is often caused by an elongation of the eyeball that happens when people are young.

According to the research, the problem is being caused by a combination of factors - a commitment to education and lack of outdoor light.

Professor Morgan argues that many children in South East Asia spend long hours studying at school and doing their homework. This in itself puts pressure on the eyes, but exposure to between two and three hours of daylight acts as a counterbalance and helps maintain healthy eyes.

The scientists believe that a chemical called dopamine could be playing a significant part. Exposure to light increases the levels of dopamine in the eye and this seems to prevent elongation of the eyeball.

"We're talking about the need for two to three hours a day of outdoor light - it doesn't have to be massively sunny, we think the operating range is 10-20,000 lux, we're not sure about that - but that's perfectly achievable on a cloudy day in the UK."  (BBC.co.uk)