I wear a pair of shooting glasses with removeable lenses made by Bud Decot. When I began to experience the "Aging eyes" syndrome I called them to discuss what we might do. I don't know all the proper "Optometrist" terminology, but in simple terms, the solution was to keep the weak side lense as it was, for seeing at distance ( the target) and use a new lense on the strong side, specially ground to see the sights, then keep both eyes open. The brain will figure it out.
A couple of other observations on the vision/iron sight topic I've made over time. These are not opinion, but rather based on my experience shooting with bad eyes :
1. Peep sights, like the Lyman 57ML work well, but you surrender the ability to shoot in low light. Of course, you also have left the more traditional "fixed sight" game behind. That said, I still enjoy using such a setup for shooting bench rest on a nice sunny day.
2. Using a "peep" type sight I have learned that my precision ( i.e.: SIZE of groups) varies directly with the size of the opening. I have screw in inserts with several different opening sizes. I have spent a fair amount of range time doing test and evaluation for my own edification. Larger sized "peep" openings work better in lower light levels, but you give up a little on precision ( groups open up as peep size opens up).
3. Removing the "peep" insert altogether and shooting a "Ghost Ring" works just fine for hunting in my area. Shots on game tend to be pretty close...well under 100 yds...and "minute of deer/hog" is still quite achievable using a ghost ring set-up.
4. Adding something like the Merit Eye Disc definitely helps see the iron sights but can be a little clumsy in the woods. I never got "a piece of electrical tape on the strong side lense" to work for me, but I know some who have.
For those new to the "Aging eyes" situation, I hope at least some of this helps.