After reading a post on eye sight problems, I had a go at making an "iris" out of gaffa tape over my spare pair of specks, with a hole burned through (1 ml). It definitely helps to see the front sight. I tried shooting the same target, with and without the iris. You can guess what happened!!! Its early days yet, but there's something in this. Apparently you need different sized holes, depending on lighting, but Ive got a prototype to start with. Its going to save wasting pellets, because I now know that I was thinking I was on target, but really,that slightly out of focus front sight made such a discrepancy on shots. Its a bit of a faff, but any one who is having the frustration of being sure they are aiming correctly, but missing!!! (assuming failing eyesight) should try this. I am talking here of one hand shooting, because you can get away with it a bit using two hand hold.