Doggles sells eyewear for dogs. There are many different colors and sizes, as well as swappable lenses!! The sizing chart seems to suggest that an XS size would fit your standard 60 or 70cm BJD’s head. [I assume that the “head size” refers to circumference.] According to some more detailed stats, the XS head band adjusts from 5 to 13 inches, and the lenses are 1 inch high and 1.25 inches wide.
Doggiduds also sells goggles for dogs. No changeable lenses, but slightly cheaper.
EDIT: I just bought a pair of the XS smoke/chrome ones…strictly for research purposes, you know. $18.00, free shipping…and that was the lowest I could find after shopping around. Hopefully I can customize them with steamy, punky gimcracks… EAT MY PRICE TAG, ANOTHERSPACE!