'Pin hole glasses'. The principle works well but not with multiple holes.
The easiest and cheapest solution is to buy a cheap pair of flip-up sunglasses that clip over your specs.
Take a Sharpie or like and get down behind the rifle. Aim through the sights and at the same time bring the Sharpie up to the front of the lens and make a mark in line with the front and rear sight. Now, with a hot wire, make a hole through the lens over the mark. Rub the lens over with a green scrubber from the kitchen, clean and spray over with some matt black car spray. Your choice as to the size of the hole. If you want to you can cut out the other lens.
I have two holes in mine. One for rifle, one for pistol.
You now have an excellent equivalent of an aperture fixture on your specs EXCEPT that it won't fall off, it costs next to nothing, it can be flipped up when not shooting and it protects your spectacle lenses from any blow-back.
I made one probably 10 years ago, keep it in the cheap clip over cover it came in, still perfect.
Good luck,