I'm sure its been covered here often, but I'm right-handed, and definitely left-eye dominant, no question about that. BUT, Thursday on the range, for the first time in my 2 years of shooting now, I tried closing my left eye and using my right eye. (Had handguns on Thursday) It seems that there was very little difference in accuracy. I forgot to try keeping both eyes open, will try that next week. I'm just past 60 now and my eyes are fine except for reading newspaper-size print. Can read it, but a hassle, so use reading glasses. Keeping the sights level for the vertical accuracy not a problem, but placing the front sight dead center in the rear sights is the problem. Shot placement is either left or right, and of course sometimes high and low too, but the left/right the major problem. I'm guessing prescription glasses would help me see the sights better.