For any of you older guys who are having a problem with a "fuzzy" rear sight, I solved that problem for myself. Working with my eye doctor he fitted me with a left eye contact, I shoot left-handed and with my left eye. He had me measure the distance from my eye to the rear sight, did some eye examination and then fitted me with a lens that in my case is only 1.5X magnification. I can now see my rear sight without any fuzziness and this low magnification in the one eye in my case does not affect the clarity of my distance vision.
It has made an unbelievable difference. May not work for everyone, but it's worth a try.
Takes a little practice putting it in. I use the daily disposable ones so I haven't tied up a bunch of money in them, about a buck a piece.