Both open, but I'm very right eye dominant. I think it is because of years of shooting shotgun and rifle, which I shoot both eyes open also. But even with both open, my left never opens as much as my right. My wife even commented on my &quot;droopy&quot; left eye. I said it's not droopy, just not used very much. <img src=icon_smile_wink.gif border=0 align=middle>