Many of us ole timers will get "Far Sighted" ...meaning we can see great further out in distance but need reading glasses for close up...arms seem to shrink...lol
As SCHOOCH stated ..the clarifier is an option...
If its not...
-A longer sight base rail...will help with focus
-A larger peep
I dont use a peep which also helps...
A thing to remember is we dont focus on the pins to begin with...
when shooting we focus on the target...stare a hole on the x of the X...aim small-miss small...pick a spot...
Then the pin- without refocusing on pin -is brought onto target in Peripheral vision...biggest issue is shooters who try focusing on pin than target than pin...etc....thats when things get very blurry
-Smaller pins or experiment with brightness
Some things to ponder...near everyone reading this at some point will need reading glasses...lol
Neil