I had the same question earlier in the year, as I always just wore my street glasses, and dealt with all the watery eyes, dry eyes, rain drop hits, and the like. But I found an alternate solution, and it may help you:
Prescription safety glasses. They are not as expensive as dedicated cycling glasses. I got full wrap black plastic full frame safety glasses for $133 at RX-safety in New Jersey. So far, they have been the cat's behind. I could have gotten 10% off if I had facebook, but I don't. So it may be an option to explore.