I remember doing the MS150 9 years ago with my regular prescription sunglasses (not wrap-around). My eyes were totally dried out by the end of the 2nd day. The last few miles I was riding while alternately closing one eye, to give the other one a rest. It was awful!

Now I ride with contacts and wrap-around riding glasses - what a difference! My eyes still water occasionally, but I've never had the "dry eye" syndrome again.