Wow. I never knew. I don't want to pay Brand prices to Luxottica.
RichSPK's googles look to be non Luxottica. There are quite a lot of prescription goggles from China.
I have some that I used for karate but they would be no good cycling in the drops.
Gormless Old Person Pretends to do Karate by
Timothy Takemoto, on Flickr
These are below are taller, less than 30 USD, and convert to spectacles too - one can convert the strap to arms and vice-versa. Again, if I wore them upside down they would be okay.
Aliexpress.com : Buy diopters sports glasses for prescription lens for basketball football with arm replaced to strap from Reliable sunglass suppliers on sport's very cool