Who says it's bad for your eyesight?
Playing action video games can boost an aspect of adult vision previously thought to be fixed, a US study shows.
Researchers found playing the games improved the ability to notice even very small changes in shades of grey against a uniform background.
"Contrast sensitivity" is important in situations such as driving at night, or in conditions of poor visibility.
The Nature Neuroscience study raises the possibility of using a video game training regime to improve vision.
Contrast sensitivity is often one of the first aspects of vision to be affected by ageing.
It can also be affected by conditions such as amblyopia, known as "lazy eye".
Improving contrast sensitivity usually requires physical changes in eye optics, through eye surgery, glasses or contact lenses.
A team from the University of Rochester studied expert video game players playing games involving aiming and shooting at virtual targets.
They found that they had better contrast sensitivity when compared with players who played non-action video games.
These results were not because people with better contrast sensitivity were more likely to be action video game players - giving non-video game players intensive daily practice in video game playing improved this group's performance on tests of contrast sensitivity.
Crucially, the improvements in this study were sustained for months or even years in some cases, suggesting that time spent in front of a computer screen is not necessarily harmful for vision, as has sometimes been suggested.
Lead researcher Dr Daphne Bavelier said it was likely that several aspects of playing video games combined to produce the beneficial effect.
The games immersed players in an environment where they had to be constantly ready to react to unpredictable events, and where visual information had to be responded to instantly in very precise physical ways.
In addition, the mere fact that the games were stimulating and rewarding should not be overlooked.
Dr Bavelier hopes to make use of the discovery to develop new ways to treat amblyopia.
The hope is that by using video games researchers can encourage the two eyes to work together, and restore the stereo vision which is lacking in people with a lazy eye.
Professor Gary Rubin, of the University College London Institute of Ophthalmology, said he was surprised by the findings.
He said other work had shown that it was possible to train people to improve some aspects of their vision - for instance, to widen the visual field.
But he said: "Contrast sensitivity is a very basic visual function, and usually they are more difficult to alter in adulthood.
"This is a small study, showing a small effect, but it was carefully done, and merits further investigation."
John Sloper, a consultant at Moorfields Eye Hospital in London, said other researchers were also examining the potential for using video games to treat amblyopia.
He said: "There is some evidence that the visual system can learn."