New Zealand eyewear maven, Coral Mazlin, is regularly posting on Tumblr about the process of manufacturing the frames she designs.
It's fascinating! I highly recommend reading it if you're at all interested in eyewear design.
First, check out the production process on her site
...and then read the diary of her latest manufacturing trip.
If you live in New Zealand and would like to purchase her frames, I recommend talking to the super-lovely folk at Occhiali.