The bloodshot appearance of the eyeball after playing video games for a long period of time.
Ex. 1: "Dude what's up with your eye?"
"I was playing C&C3 till like 4am"
"You got some serious Xbox eye"
"Yeah, well, GDI can kiss my ass"
Ex. 2: "Dude I can't play Halo 3 anymore, I got a serious case of Xbox eye"