A while back, there was a thread, maybe in over the back fence about using readers for helping shooting. A link was posted so I ordered 3 pair glasses, @ $24.99 ea pair). 2 of them, at .5 and .25 diopter, were called reading glasses. The third were called computer glasses so I ordered .25 diopter. I attempted to get them locally, but none of the stores which sold readers could order in anything lighter than 1.0 dipoter, which were too blurry on the target.
I've been experimenting with the .25 and .5 dipoter glasses. The .5's make the sights slightly sharper than the .25's, but the target is slightly more fuzzy with the .5's, of course, than the .25's. It's a trade off, and I sooner or later through testing, I will decide which is better - for me.