Metal frame.
Mirrored sun lenses.

Dampen the glasses and wipe them with the microfiber cloth provided. Remember to wash it regularly.
You can also pour a drop of dishwashing liquid mixed with water on each lens, rub gently with your fingers, rinse, and then wipe with the microfiber. Same for the temples.
Do not put your glasses on the domed side of the lenses and when you are not wearing them, slip them into their case.