Washington: Playing video games could help improve the vision of adults suffering from amblyopia or lazy eye, scientists have found.

Researchers at the University of California, Berkeley, found that adults with amblyopia -- a brain disorder in which vision in one eye does not develop properly – experienced marked improvement in 3-D depth perception and the sharpness of their vision after spending 40 hours playing video games.

Amblyopia is the most common cause of permanent one-eye visual impairment among young and middle-age adults, which affects 2 to 3 out of every 100 children.

Though it can be successfully treated in children by putting a patch over the "good eye" to force the brain to use the weaker "lazy eye", few options are available for adults with this condition.

"These findings are very encouraging because there are currently no accepted treatments for adults with amblyopia," study author Dennis Levi was quoted as saying by LiveScience.

"A lot of eye doctors’ start closing the books on successful treatment after age 8 or so because of the widespread belief that amblyopia can only be reversed during a critical window of development in the visual cortex. If the disorder is not corrected in childhood, the damage was thought to be irreversible," Levi said.

That thinking has started to change in recent years with research finding it is actually possible to improve vision in adults with lazy eye. For instance, intense training on a task like aligning two horizontal lines sometimes leads to a 30 to 40 per cent improvement in visual acuity, the scientists said.

For their study, published in the journal PLoS Biology, Levis and his team recruited 20 volunteers, aged 16-60, with amblyopia. They were asked to spend 20 two-hour sessions playing action and non-action video games, wearing a patch over their good eye.

It was found that the volunteers gained between 30 t0 50 per cent increase in visual acuity on the standard letter chart used by optometrists.

"I was very surprised by this finding -- I didn't expect to see this type of improvement," said researcher Roger Li, an optometrist at the University of California, Berkeley.

However, the researchers cautioned that patients should not attempt to treat their amblyopia by themselves. "People definitely need to work with their eye doctors," Li added.