Video games that contain high levels of action, such as Unreal Tournament, can actually improve your vision.
Researchers at the University of Rochester have shown that people who played action video games for a few hours a day over the course of a month improved by about 20 percent in their ability to identify letters presented in clutter-a visual acuity test similar to ones used in regular ophthalmology clinics.
In essence, playing video game improves your bottom line on a standard eye chart.
"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."