don't think it matters much because you're looking exactly where you're aiming in fps, unlike irl with a gun or w/e.

at first thought this might affect your aim or reaction timing to stuff happening on the edges of the monitor, assuming you have a big monitor.

other then that, I don't see it being an issue at all for fps'

I did this thismorning.

Turns out I'm left eye dominant and right handed.. but I really don't think it matters as I've always used my right eye for aiming things and always had a pretty good shot (dart's.. air rifles etc). Plus my eye sight in both eyes are the same imo.

I'm really trying to think of an application where this affects me but I can't.

This isn't very accurate , having repeated the procedure i've realised sometimes i focus with my left eye and others with my rright one.... theres no dominance by either.
You can even switch focus move your hands left and right and the object will center with either one . oO



Edit: i should have read this first :X

"however in a small portion of the population neither eye is dominant. Dominance does appear to change depending upon direction of gaze"

have you tried wearing an eye patch?