Here is detailed tutorial on how to 3d scan prescription eyeglasses lens by taking photos of a lens covered by masking tape:
When you have a scanned lens (or lenses) you can design your custom 3d printable frame:
There are a few simple(ish) steps involved, but nothing an average user can't master ...
And here is the final result:
You can print the frame on your home FDM machine but the results will be more rougher. For best quality use a SLS or PolyJet 3d printer.
Great work Aaron!