I tried "regular" bifocals of different heigths, and also the progressive lenses. I never could get a consistent sight picture, and the point of impact varied with the two types of lenses. Then, as an exercise based on the idea I might not have time to put on my glasses if a BG broke in my house at night, I did some shooting with plain lens safety glasses, and discovered I can shoot much better without the corrective lens. If my eyes get worse, I may have to change, but for now I will use the plain lens glasses.