Ron, thats not magnification your talking about, that last number is the size of the objective lens, your eye issues no doubt are related to why you need the higher numbers as its the distance across the objective lens that those numbers represent. The bigger the number the wider the lens, so the more light it lets in and the wider the field of view has, it has nothing to do with magnification though, thats the first numbers. Have you ever tried a Single Point red (or green) dot? They have no objective lens, thats right, you can't even see through them, its just a black background with a dot in there. You use one eye to see the target and the other to see the dot. No batteries either, works like a fiber optic site and the objective end gathers light, then focus' the light into a dot. No magnification, and a fairly big dot though so its pretty much an under 100yd. site. For me at least. You have to be right eye dominant to shoot right handed though, and vice/verse.
Texican, like has pointed out, it depends what your putting it on. I don't like them on rifles personally due to no magnification, some you can add a doubler, or tripler to and get some magnification but, that gets pricey and adds weight. On a handgun though I have had great success, especially with the hologram type. Since the optic quality doesn't become much of an issue when you have no magnification I generally buy "cheep" BSA, and Barska red dots. They have held up fine on my Red Hawk in .44 mag, and Gp100 in 357 mag. as well as the Super Red Hawk in .480 Ruger that I used to have.