I wear contact lenses too. Although I haven't been that fast on a bike - yet (did clock 22mph yesterday) have been out in high winds and not had a problem. I've got Bausch & Lomb Purevision lenses which do cover a largish part of the eyes (they're very comfortable and I can leave them in for a month at a time without taking them out). Perhaps the lens wasn't fitting as well as it should.

I had a pair of specs once that the frame had a fault in. I was riding my motorbike at the time when the frame went "pop", out fell the lens and I won't say what I said - it's unprintable. Fortunately, I'm long-sighted so was able to make it home OK (just couldn't read the speedo properly). It's really scary though.