When shooting handguns, it's important to know which eye is your dominant eye. One way to determine your dominant eye is to create a triangle and look through the triangle. Draw the triangle back to your face, and whichever eye it goes over that's your dominant eye. For this next method to determine eye dominance you need a friend. Stick your thumb out so that it covers your friend's nose. Your friend will see that your thumb is covering one eye. The eye it is covering is your dominant eye. Fifteen to 30% of the population is what we call cross-eye dominant. That means they shoot with one hand but use the opposite eye. One way to address this is to turn your head to the side, so that you are looking out of your support side eye. If you're a new shooter another way to address cross-eye dominance is simply force yourself to use the other eye. Knowing which eye is your dominant eye is imperative to being a good shooter.