I was with a patient last year who uses and recommends a company whereby you send the prescription note from your optician complete with an old pair of frames to a place called Ciliary Blue. Do check them out.
You won’t believe the prices and they are good quality! The big guys like Spec$aver$ and Visionexpre$$ etc. don’t like them and refuse to work with them. (Surprise surpise).
I thought this looked good, but I see they only do plastic lenses. I presently have high refractive index glass, due to my being very short-sighted. Plastic ones would be as thick as milk bottle ends!