Researchers set one test group playing first-person shooters Unreal Tournament 2004 and Call of Duty 2, and the other The Sims 2. After 50 hours over 9 weeks, FPS players were found to have a 43% improvement in their contrast sensitivity--the ability to spot slight differences in shades of grey--while Sims 2 players saw none.
"If you are driving at dusk with light fog it could make the difference between seeing the car in front of you or not seeing it," explained study leader Daphne Bevelier. After six months of gaming, a 58% improvement was seen over non-gamers.
Improving contrast sensitivity--a crucial factor in how well we see--was thought to take glasses or surgery. Previous research by Bevelier into video games' ocular benefits discovered they can improve our ability to see objects accurately in a cluttered space.