Andy George made lenses from scratch with borax, sand, and soda ash. This was just one very difficult step in making his own camera.
"Making clear glass took over a dozen tries, annealing the glass pucks took at least four attempts, and grinding the lenses themselves took at least 30 hours of continuous grinding." See the video:
While he did make use of some pretty high tech equipment, this was a great effort. Consider that the earliest known optical lenses date from 750 BC!
My favorite all time video about eyeglass lenses is this one from the Atlanta Public School System circa 1940, "Fitting Faces" about the (questionable) "Science of Beauty". The second half is a wonderful piece about how lenses were made at the time. (I've posted this before but it keeps getting pulled for some reason.) Enjoy!