Parents of young children might find it hard to believe, but playing video games could be good for your eyes.
Just ten hours of gaming for four weeks dramatically improved the vision of young men and women who as babies were almost blind.
After 40 hours of playing a violent video game, they were able to read two extra lines on an eye chart.
The simple but effective treatment was devised by Daphne Maurer, of McMaster University in Canada.
The men and women studied were born with cataracts in both eyes and as babies could see light but not detail.
Although their cataracts were removed, their vision did not return to normal.
When they were aged between 19 and 31, they took part in the study, which involved playing an action game in which they took on the role of a solider shooting the enemy or a gunman firing at aliens.
Some saw improvements in vision after just 10 hours.
After 40 hours, they able to see further down the eye chart, be better at distinguishing the direction of a movement and at telling faces apart.
Professor Maurer told the American Association for the Advancement of Science’s annual conference:
‘Video games have got a lot going for them in terms of them being an optimal visual therapy.’
The study shows violent games like Call of Duty: Modern Warfare 3 were best at helping former cataract sufferers’ vision improve.
Other work by Professor Maurer suggests that the first ten years of life are critical to vision. It is thought that during that time the brain region critical to decoding visual information is hardwired.
If it doesn’t receive enough information, due to cataracts for example, it struggles to make up the loss.
Video games have got a lot going for them in terms of them being an optimal visual therapy.
The video game helped with this because it forced the brain to work hard.
Not only did it have to process information on the line of fire, it had to crunch information on threats such as enemy soldiers on the periphery and deal with subtle changes in colour contrast.
Less dynamic games such as Tetris would not have the same effect. Other recent work has shown that playing video games can help children with a lazy eye.
The professor said: When you have abnormal visual input early in life, you get poor acuity but also other deficits, and many can be ameliorated by playing video games.