I made the switch to left handed last spring for this very reason. With that being sad, I'm starting to drift back into the habit of squinting my non-dominant eye a bit. It's not that I can't shoot with both eyes open, I just seem to do fine the way I'm currently shooting. I may practice a bit more on it this spring, but I just shot a 293-11x Vegas round today, so I'm not sure if I could improve any points with both eyes open or not.