I would like to add a comment or two for those of you who have aging eyes (and maybe had them worked on). As we get older, the eyes ability to "accommodate" (that is, to rapidly change the focus from the sights to the target) goes away. We get to the point that we can correct our vision with glasses but only for ONE area of focus. It can be quite frustrating, to say the least. However, there is some help available.
Champion's Choice has clip on magnifying lenses (available in three sizes: +1, +1.5, and +2.0. When you are trying to correct your lenses to focus at front sight range, it can even be a difference between "one hand holding "or two handed holding". It other words, you will need two different sets of clip on lenses. Understand, these are just general suggestions for MOST of us. YMMV. At any rate, I talked to the people at CC and told them that most of my shooting is two handed. I took their recommendation, and am pleased with the results. Another method is to go to a drug store that has a glasses display that allows you to try various sets of reading glasses. DO NOT take your handgun with you. These days that'll, at best, cause a riot and worst, someone getting hurt or worse. I suggest a printed card with small type that you experiment (AT HOME) with to see that what you are looking at is EXACTLY the same distance as your front sight in shooting position. Then take that card (you may have to get a bit creative in bending it, etc, so you are at the proper distance when holding it. At any rate, when you do that, try various sets of "reading glasses" from 1.0, 1.5, and 2.0 powers. Pick the one that seems to be "proper" then call Champions Choice and order:
http://www.champchoice.com/store/Main.aspx?p=ItemDetailOptions&item=CCSCL20
Now, here is the downside: the lens, if you made the proper choice, will focus on the FRONT sight. You'll be able to see the front sight quite clearly as well as the rear. Aligning the sights will be little problem. However, the target will be VERY blurred. The GOOD thing is that it doesn't matter very much if you hold center. Yeah, the CENTER of the bull even VERY blurred can be held consistently. If you could shoot small groups before, you'll be able to do it again. You just will not be able to do it quite like before, but your shooting shouldn't suffer after you learn how to do it the "new" way. At least, that is what I discovered.
Make no mistake, the Red Dot is world's easier to accommodate to. It took me about two range sessions. However, there are those of us that prefer using iron sights even if it is much harder. The flip up lenses at the correct power will allow you to do this using the "hold center of the blur" method.
Those flip up lenses are considerably more practical than trying to look through the lenses of your bifocals and shoot. Just clip them on your glasses and flip down for shooting, and flip up for walking around, changing targets, etc.
This was shot, from a makeshift rest, not too long ago, with my flip up lenses, indoors at fifty feet (first group after reaming the cylinders on my Ruger SS .45 ACP/.45 Colt convertible). I hadn't even had a chance to zero it before shooting this target with the .45 ACP cylinder:
Good luck and let me know how this works for you. $20.00 in cost shouldn't hurt anyone too much...
YMMV
Dale53