Scientists at New York's Rochester University say that playing violent video games may improve contrast sensitivity, which is often impaired by amblyopia.

According to Daphe Bavelier, professor of brain and cognitive sciences at the University changing the optics of the eye is the normal solution for amblyopia. "But we've found that action video games train the brain to process the existing visual information more efficiently and the improvements lasted for months after gameplay stopped."

Twenty two patients were tested for contrast sensitivity and these were then split into two groups. One group played an action game and the second group a visual game that did not require either quick thinking or shooting. Participants played 50 hours over the course of nine weeks. The results found that for those students playing the action game achieved an average 43% improvement in their ability to discern close shades of grey, whereas the other group showed an 11% average.

Professor Gary Rubin of UCL's Institute of Ophthalmology remained unconvinced though saying: "Contrast sensitivity is a very basic visual function and usually it is more difficult to alter in adulthood." He also observed that it was a small study, demonstrating a small effect but acknowledged that the execution was well planned and that it did warrant further investigation.