Leather crafters can be found in areas that serve horse owners. Also places that sell boots.

You still might try lesabl , you send them a picture of your prescription and they mail you the glasses or will put the lens in your frames . I did a search and it also appears other places to them online. For a leather worker , look and see if you have a shoe repair shop in your town. Most of those guys will do custom jobs. Good luck to you!