These glass frames are robust and fully functional. You can even take them to your local optometrist to get them fitted with prescription lenses!
All you need is a couple nuts and screws and you have fully working safety/sun/reading glasses.
Additional Parts Needed:
2x M5 16mm long Machine Head Screws
2x M5 nuts
If using Z-Suite. Make sure the frames are printed at 140.000 degrees on the X axis. This will allow the "grain" of the print to be a diagonal cross-section and therefore be much, much stronger. I've printed these several times and the tests were very conclusive on this point.