I have been using the EyePal device the poster has on his glasses for years.
Here is a link to get the EyePal to stick on shooting glasses to improve your sight picture. I have been using these for years, by different makers but all work the same when I was shooting
Bullseye pistol matches and now I use them for open sight pistols and my flintlocks for hunting and targets. I have used one set for over 4 years. Keep clean and will last forever.
You can get pistol only or a set, one for pistol and one for rifle. They are cheap help for shooting. I have about 4 packs of them. One in my truck console, one in my BP shooting box, one in my modern pistol box and one on the work bench for dry fire practice.
EyePal-peep for shooting
Mike