A new study found that adults who play a lot of action video games may be improving their eyesight. A group of 22 students was divided in two, one playing shooters Call of Duty 2 and Unreal Tournament 2004, while the second played The Sims 2, a sim game. At the end of the 50-hour trial, the action game players showed an average of 43% improvement in their ability to discern close shades of gray, while the Sims players showed none.