welll, i have a lazy eye... which is like being cross eyed, but it goes outwards instead of in... i always had great periphreal vision (i can't focus both eyes at the same time, but which ever is going off to the side gives me atleast another 10 degrees of perphreal...)

but i too noticed when i started smoking my eyes became sharper.. i mean i always had good vision, but i'm a hell of a lot quicker to see them stoned then sober.