I already wear bifocal lenses. Trifocals would just add to my problems. Besides, the area where a specific shooting correction needs to be made is the upper inner corner of the appropriate lens.
There are ways to do this, chief among which is to have a "spot" balsam-glued to your lens. Spots come in a couple of sizes, and can be placed anywhere on a lens, so you can have a very localized correction.
You could have special shooting glasses, of course. But I don't like to carry extra glasses. I have enough in my pockets as it is. Further, do you really think that a bad guy would be kind enough to wait, while I shift to my special shooting glasses?
So I don't use any of these solutions.
All of my pistol shooting is defensive, close-range work. I don't even practice at greater distances than 20 yards. Up that close, and shooting that quickly, it really doesn't matter whether I'm focussing on my front sight or on my target. Something's going to be blurry, and it doesn't matter a bit. (Usually, I do focus on my front sight.)
When I'm shooting at the really close distances, or in low light, I don't use the sights at all. (No, that's not as nonsensical as it seems.) Instead, I use the entire rear-end silhouette of my pistol, to make sure that I'm aligned correctly on any kind of target. I am practiced enough to be able to tell just from that silhouette, whether or not everything is in correct alignment. It's called—slightly erroneously—"slide shooting."
Closer than that, or in the lowest light, I shoot without ever seeing the gun. That, too, is the result of a whole lot of practice. No, I don't "shoot from the hip" if I have time to raise the gun, because hip shooting is usually pretty inaccurate at anything past "bad-breath distance." Also, I never shoot in the total dark, because if you are in the dark you cannot properly identify, or even localize, your target. If it's that dark, I'll be using a flashlight.
For rifle shooting, I do concentrate on seeing my front sight—if I'm using iron sights. A rear "peep" sight takes care of the rest, centering my eye automatically, even though it looks extremely fuzzy.
However, most of the time I use a low-power scope. That takes me out to about 1,000 yards, for "practical" (not bullseye) shooting, assuming a good zero and an accurate range-card (attached to the rifle).
Scopes in general will put everything, scope, reticle, and target, all on the same plane of focus. You see everything clearly. Since the scope I use is the "Scout" style, placed between nine and 12 inches from my eye, it is correctly within my normal range of eyeglass focus.
For all of the shooting noted above, I use my "everyday" glasses prescription, ground into the upper part of my lenses. The lower part of the bifocal is only for reading. For really close and finicky work, I take my glasses off entirely.
(Oh, yeah... I forgot to mention age: I'm 73 years old.)
Does that help?