This is a great vintage video from "Loveliness Laboratories" on how to choose (then) fashionable eyeglass frame styles and how eyeglass lenses used to be made.
The style half of this video is hilariously dated. The half dealing with eyeglass lens manufacturing is fascinating. Lenses used to be made primarily of crown glass, as shown. What is amazing is the shear amount of equipment, time, energy, and technicians it took to produce them. It looks like it was probably pretty close to smelting steel or creating new orcs, or something...