There is a choose your poison aspect to this problem. For 10 years, I had a commute along a busy 2 lane highway where everyone was driving 65. The grime and road spray was so bad that wearing glasses in the wet was out of the question. So I wore cheap sunglasses that I'd popped the lenses out of so I could still use my mirror. The technique is effective even if dorky looking. However, I routinely hit speeds on my current commute that really call for eye protection, especially in cold weather.