oh i have to add something concerning the focusing eye:
somebody made a test some months ago & the result was that people playing shooters get more details of their natural environment than people who don't play or beat up with tetris ( )
so if you play shooters, i.e. you won't get more details in somebody's face, but you'll notice more objects & forms when you e.g. enter a room you've never seen before (that would also mean you notice more colors, and by this, your world is more colourful and so also more interesting & happier than your mates' world not playing ut200x  )