Slight area of eye is red after gaming. what causes this?

Eye irritation: Computer use and prolonged reading is associated with a reduced blink rate. When you blink, your natural tears lubricate your cornea and conjunctiva (the clear dome over your eye and the "skin" on the eyeball). When conjunctiva is less lubricated it can become inflamed-thus a red eye. Use some lubricating eye drops prior to and during these gaming stints.