With the weakness in my left eye, I thought that a magnifier might help. So I bought a Fresnel lens on eBay. It means I get a flat, light magnifier, and it also has LED lights. The magnification is x3
The light is too dim to be useful, and the magnification doesn't look like X3 to me. If you look at the picture of a 100 euro note, it looks about 10% bigger, not 200%.
So it was a nice idea, but the implementation wasn't good.
Maybe I'll find a better implementation.
Then I thought, suppose I connect a camera to a screen, and magnify digitally instead of analogue with a Fresnel?
Then I thought, that's what a Smartphone is. Then I thought, I expect someone has already done this.
So I looked and found "Magnifying Glass + Flashlight", a free app in the Apple store. I installed it, and it's rather good. It makes it possible to read text on a page with my left eye, but the magnification has to be x5 and it doesn't get much of the page at a time.
Maybe I'll work on this a bit.