I wear Rx glasses and have had a pair of Rx sunglasses. Throughout the day I'll get a random piece of grass come up and hit my lens and stick, and sometimes hit my eye. The Rx sunglasses I used to have before some jackhole broke into my truck and stole them (among other things) were amazing. Costa Del Mar Fathom. They covered my eye completely and were a plastic lens, they were a great all around pair. I loved the blue mirror tint too, just because my head is looking at you doesn't mean my eyes are.
But on to the point of the Rx glasses, some of my family work in a Fortune 500 company and wear glasses and they can get these little side shields that snap onto the frame of your glasses, they look goofy...but they must work.