Researchers at the Erasmus teaching hospital in Rotterdam say they now have genetic proof that light processing in the eye plays a role in nearsightedness, providing further evidence that children should play more outside.

Last year, research by Erasmus MC, based on a continual study of a group of Rotterdam children, had already shown that nearsighted children spend less time playing outside.

The new research, published last week in the journal Nature Genetics, identifies 161 genetic factors associated with glasses prescriptions and myopia. The most important factor researchers found was the detection and processing of light.

‘This is molecular confirmation of what had previously been shown by epidemiological studies: light, or rather the lack of it, is an important trigger for the development of nearsightedness,’ the researchers said.

A person who is nearsighted has an elongated eyeball, which means that the light focuses in front of, instead of on, the retina which causes distant objects to appear blurry.

Myopia has become increasingly common over the past years and nearsightedness now affects 50% of those in their 20s.

The findings, says researcher Milly Tedja are ‘particularly alarming for high prescription glasses wearers as it is they who are at higher risk of ophthalmic problems.  We expect myopia to become the main cause of blindness in the future.’

Children

‘This is why we recommend that parents get their children to alternate close-up work with being outside for at least two hours a day,’ research leader Caroline Klaver said.

Some 25% of the children in the study of children were nearsighted at the age of 13, compared with just 2.5% at the age of six.