Swampy you have hit the nail the head. I have worn glasses since elementary school and was a pretty good handgun shot for years. Before retirement I had more sets of glasses then many, I had standard vision, bifocals, and computer glasses. Actually I had five pairs of glasses because I also had sunglass in standard vision, and bifocal.$$$
A good part of my life has been spent in the woods, rock hopping up a stream, crossing on a log, or doing other activities where vision goes from close to far. Even going down stairs can be tricky with bifocals. In the office I wore bifocals, out on the road standard vision glass, and next to the computer were my computer glasses.
In the process the little group in the center of mass grew larger. I have not had a major problem with scopes and peep sights. There was a time I would shoot Digger Squirrels with a 2.5 inch Model 66, I think the Squirrels are smaller now days because of Global Warming.
I have heard, and read about the Merit Optical Device for years but never considered it practical for LE work.
Yesterday my wife asked me how my morning walk went; I responded that it was clear that I am closer to seventy then to twenty.
Gun Runner and I start out at the ten yard line blasting away at targets, and then we move them out to the 25 yard line. Gun Runner shoots circles around me, what is surprising at his advanced age. He tells me the issue at 25 yards is his low velocity loads out of his 44 Magnum, the trajectory is such that the bullet drops below the target. I have notice the same thing with my pistols, but one must conserve on powder and not beat-up their guns.
The good news is that most defensive shooting occur at less then 10-yards, but I know that he is concerned. He gave me a box of 00 buckshot for the shotgun the other day.