University of Rochester released a new study suggesting that playing action video games can indeed sharpen your vision. This however, does not apply to all types of video games. Shooting games, for example, which are fast and more action packed have been proven to produce this positive result. Slow games like puzzles show no sight improvement.
Here are the technnicalities - The human brain ultimately adapts while playing video games as the brain's human visual system pathways are pushed to the limits. Playing with video games changes the way brains process visual information. It trains an individual to see tiny, closely packed letters more clearly.
In future, this method could become a vital form of rehabilitation therapy to help visually impaired patients.
Now that you're armed with this knowledge, you'll have another excuse not to put down that playstation! :D