Short-sightedness on the rise in the young

Young people of European ancestry are more likely to be short-sighted than older generations, according to a new study of over 60,000 people.

Results combining figures collected between 1990 and 2015 showed more than 3 times as many short-sighted participants aged 25-29 than those in their early 70s. The researchers, who also looked at long-sight and astigmatism, estimate that more than half of adult Europeans have some form of refractive error (trouble focusing).

People with short-sight (myopia) can see near objects more clearly than ones that are further away. Distant objects look blurred because light coming into the eye is focused in the wrong place. Instead of reaching the retina, which is at the back of the eye and contains light-sensitive cells, light comes to a focus point in front of the retina. This is usually because the eyeball is too long but can also be because the cornea (the front surface of the eye) and the lens are too curved.

Severe myopia increases sight loss risk

Although blurred vision is usually easy to fix with glasses or contact lenses, people with high-myopia (severe short-sightedness) are at risk of sight loss. If the eyeball gets too long, the retina can tear or even come away from the layer of blood vessels that supply oxygen and nutrients (a ‘detached retina’).

High myopia can also cause glaucoma (damage to the optic nerve) and myopic macular degeneration in which central vision becomes distorted or blurred.

A quarter of study participants (25.2%) had hyperopia (long-sight due to the eyeball being too short) and almost a quarter (23.9%) had astigmatism (where the front of the eye is more rugby-ball shaped than rounded).

Overall results for people aged 25-90 showed that myopia was the biggest cause of refractive error, affecting almost 1 in 3 people (30.6%). The researchers estimate that this means almost 230 million people in Europe are short-sighted.

Younger people were more likely to be affected by myopia than older people, whether mild, moderate or severe. Almost half (47.2%) in the age group 25-29 were myopic compared to 37.1% at age 45-49 and 13.9% at age 70-74.

High priority

“Based on the study data for high-myopia, the authors conclude that there are 20 million people across Europe who are at higher risk of sight-threatening complications and of course this figure is likely to be even higher if we look at the whole adult population,” said Dr Dolores M Conroy, Director of Research at Fight for Sight.

“Finding out more about the factors that influence refractive error was a high priority identified by the James Lind Alliance Sight Loss and Vision Priority Setting Partnership, so it’s very interesting to see that younger people are so much more at risk than they were in previous generations. Now we need to unpick the contribution of changing patterns of lifestyle behaviour compared to genetic factors.”

The research was published in the European Journal of Epidemiology. One of the authors, Mr Paul J Foster, was part-funded through Fight for Sight.