I'm a glasses wearer but I rarely wear mine on the water. I have difficulty wearing contacts but have begun to wear them after once mistaking A mark for the finish line pin earlier this year (and losing a couple of positions!). I have an astigmatism that mostly affects my depth perception. The discomfort from the contacts (My eyes don't make enough tears) is less than the pain of doing something stupid! The contacts are usually glued to my eyeball at the end of a full day on the water.
I've considered several options but the contacts coupled with sun glasses that fit tightly to my face seem to be the best combination for me...I haven't been happy enough with a single pair of sunglasses to consider spending the dough on a prescription. Although I might act like it sometimes, I'm not 10 years old either.
I've played with several different types of eye wear for races and have been pretty impressed with what a ski goggle does for blocking UV and water spray...why not wear the ski goggles over the glasses while on the water?