Playing "action" video games improves a visual ability crucial for tasks like reading and driving at night, a new study says.

The ability, called contrast sensitivity function, allows people to discern even subtle changes in shades of gray against a uniformly colored backdrop. It's also one of the first visual aptitudes to fade with age.

That's why a regular regimen of action video game training can provide long-lasting visual power, according to work led by Daphne Bavelier of the University of Rochester.

Previous research shows that gaming improves other visual skills, such as the ability to track several objects at the same time and paying attention to a series of fast-moving events, Bavelier said.

"A lot of different aspects of the visual system