You are much more apt to glance back to the barrel when you are only looking in the general area of targets rather than "centering" on them. Centering means that you are looking hard at targets.
Looking at the leading edge of targets is a good suggestion. Even better is concentrating your vision where you want the center of the pattern to impact the target. It might be at the leading edge or ahead of angled targets.
Centering can be practiced almost anywhere. Instead of looking at whole things, look at a particular part of them. For example, instead of looking at a picture across the room, look at the corner or at a small object in the picture. Instead of looking at a whole car, look at a tail light or a door handle. The same thing can be done with targets while waiting for your turn to shoot.
Centering is a learned technique. When you look at something, anything, practice centering your vision on a particular spot on the object. With practice, you will eventually be able to see targets or spots in front of targets. It will increase your shooting accuracy and make bead checking a thing of the past.
Rollin