Contrary to what our parents used to say, new research claims that playing video games actually improves eyesight. Tests were conducted on two groups of non-gamers, one of which received 30 hours of "training" on fast-paced action games such as Lost Planet and Halo. This type of game pushes the human visual system to its limits, causing the brain to adapt and, well, level up your sense of spatial resolution, allowing you to see closely-packed objects more clearly.
Unfortunately, playing Gears of War won't help you lose the contact lenses. Most visual problems have to do with the eye itself, whereas video games only benefit neurologically-related conditions.
But hey, an excuse to play video games is an excuse to play video games.