I wear contact lenses, and I cannot ride any meaningful distance without sunglasses of some sort. I have been too cheap to buy some nice clear or amber lens dealies, so I even wear plain ol' sunglasses when it's overcast or even raining. One of these days I will break down and get a nice set with interchangeable lenses so I can swap depending upon conditions. Even without the contacts, I think it would be pretty difficult to ride very far without; the wind really dries out the eyes.