Action video games may be frequently cited by detractors as sources of moral decay and violence, but new research indicates that they can improve your vision.

Gamers who play action video games such as Unreal Tournament or Quake for a few hours a day over the course of a month improved their ability to identify cluttered letters -- a common vision test -- according to new research from the University of Rochester. The research, funded by the National Institutes of Health, will be published next week in the journal Psychological Science.

"Action video game play changes the way our brains process visual information," says Daphne Bavelier, professor of brain and cognitive sciences at the University of Rochester. "After just 30 hours, players showed a substantial increase in the spatial resolution of their vision, meaning they could see figures like those on an eye chart more clearly, even when other symbols crowded in."

By way of contrast, gamers who played Tetris almost daily for a month showed no improvement.

Bavelier says that action video games change the brain's visual processing pathway and that these changes carry over to other activities.

The challenge for Bavelier and graduate student Shawn Green, who helped with the research, was finding students to test who didn't already play video games. "That alone was pretty tough," says Green. "Nearly everybody on a campus plays video games."