Two factors that will clear things up (if you haven't tried):
Always opt for the high index plastic lenses--not polycarbonate, which presently is the default lens material in most places. After years of comparing, I can tell you with certainty that polycarbonate lenses distort more as you look away from the center (as in turning your head while aiming). High index plastic is clearer, like glass. It's a couple bucks more (not much), and places like Lenscrafters will take a couple extra days ordering them, but once you see the difference, you'll probably never switch back.
Beyond that, go for smaller, rounded lenses. The wide rectangle lenses, even though "short" in profile, have all the extra lens material on the outside edge, like full-size 'nerd' glasses with the top and bottom portion cut off. When they're rounded, you rid yourself of a lot of that extra lens. Less depth/less material, I am convinced, equals less distortion, especially if the lenses are the right material.
I'm no doctor--just a lifelong shooter who's gone through the same frustration with glasses not being clear when you don't look through the center. High index plastic and small round lenses are the solution.
BlkDog: So you're no stranger to Camp Perry, I presume? 14s, Carbines, and Garands?