if you were shoot low and the gun had no adjustment for elevation what do you do?
If you were to sell it - do you adjust it back?
im at a loss how anyone could see a sight differently - they still line up the sights the same way what would be different on a different shooter - front sight rear sight or your eye? The target is in the same place right?
if your not hitting where your aiming at consistently then your doing something wrong consistently.
if you bench your handgun and the top of the sights are level and equal daylight between the sights and you point of aim centered on the top of the front site post it will hit where your aiming.
so what are you doing to consistently miss?
as far as cataract surgery - as long as you have a clear focus on you front site i dont see why that would change anything