The really annoying unconscious twitching of the eyelid of either one or both eyes caused by heavy fatigue. It is not a painful condition, but the twitching does become very annoying over time. The only cure is regular deep sleep over a number of days. Called gamer's eye because so many gamers experience it after spending day after day sitting up until 2am playing Counter-Strike (or WOW, or some other game), then getting up at the usual time to attend work/school/college/etc.
Person 1: Man, I've been playing Counter-Strike for three days straight and now I've got the worst case of gamer's eye. Look closely, can you see my eyelid twitching?
Person 2: You are such a geek. You should switch to World of Warcraft; it kicks CS's ass!
Person 3: Dude, you know I can't play WOW; I'm heterosexual!