I wear no-line bifocals so I'm constantly adjusting them for best sight picture. Dang! It's tough getting OLD! LOL!
Yep,it's hard to get good sight picture anymore. In my 30's I shot competitive pistol and rifle, but alas, now in my 60's the eyes just aren't what they used to be. However, proper technique is still to focus on FIRST SIGHT and let rear sights and target blur some. Focus on the first sight and you'll shoot better.