No, you don't need trifocals.
My suggestion to use reading glasses was not the hare-brained idea of another dumb redneck...
Suspend disbelief for at least one trip to the range, try using some new, inexpensive readying glasses, and see if you don't shoot better!
I made that recommendations after watching a number of guys at our local range improve dramatically. They did it based on the advice of a couple of local opthamalogist who specializes in sports medicine. I talked to them, and then I talked to their eye specialists. The one I worked with suggested that for me and for a number of shooters at our local IDPA club.
It works.
On a related note: there's just no way practical way to make tri-focals work in shooting unless you're doing nothing but SLOW FIRE at a fixed, unvarying distance. If you go that route, you'll spend so much time trying to line up and look through the right part of your glasses, you'll never get off a shot. Single focal length lens makes it far easier.
Top notch shooters, especially BULLSEYE shooters, preach that you should FOCUS ON THE FRONT SIGHT. There's a reason for that. You don't need to see the target clearly, but its critical that you see the front sight clearly. A fraction of an inch misalignment at the pistol-end translates to VERY BIG ERRORS at the target end...
Your current reading glasses sound as though 1) they won't work, and 2) probably are no longer right for you eyes. (My optician made the point, yesterday, that as your eyes age, you're forced to pull reading material closer and closer. Sounds like that's what's happening to you. You ought not have to do that. If your glasses are right, you'd not have to do look at things, "close up."
Buy a pair of cheap reading glasses at the drugstore, and take them to the range. Find some that let you focus on something that is the same distance as the front sight of your gun. Its an easy test.
With that second effort, I'll shut up and say no more.