EYE experts are advising parents to encourage their children to spend more time outdoors in the summer holidays, as research indicates that a lack of sunlight and too much time playing on technology may be a cause for increasing numbers of children having to wear glasses.

In the past myopia (short-sightedness) was attributed to genetics, but in recent years the problem has reached epidemic levels leading to the belief that environmental factors may also contribute.

In part this is caused by people spending too much time indoors, staring at digital devices or other close tasks with not enough time spent outdoors. Bright sunlight releases dopamine and other chemicals to help regulate eye growth.

Experts warn that if present trends continue more than four billion people will need glasses by 2050. Experts have also warned that high myopia, a condition that can lead to serious eye complications will triple, leaving an estimated 938 million people at risk of losing their eyesight by 2050.

A recent study found that children in the UK are now developing myopia at a younger age, being more likely to develop the condition between the ages of six and seven and 12 and 13, rather than in their teenage years.

Andrew Bridges, director of professional services at Leightons Opticians and Hearing Care, which has a practice in Downing Street. Farnham, said: “Most children play on a number of digital devices staring at a close screen or task.

“For all close tasks including digital devices it is important to remember the 20:20:20 rule, every 20 minutes look away from the screen into the far distance for 20 seconds to relax the eyes and blink 20 times to stop the eyes drying out.

“It’s vital that children spend more time outside every day. The first critical phase of eye development is up until around the age of eight, so it is important to have every child’s eyes examined before this time.

“A first eye examination can also detect eye conditions which may have gone previously undetected and may otherwise be mistaken for specific learning or reading difficulties.”