I also wear perscription glasses and thus tended to not wear other eye protection on top of it because of the discomfort. While I would occasionally get a peice of brass flying back at me from my 1911, it was never often enough to convince me to wear additional eye protection. Strangely enough I have found that the biggest eyeball offender are .22 semi-autos. It seems that almost every time I shoot one, regardless of the make or model, I reliably get a little fleck of something in my eye nearly every single time. I don't know what it is, but whatever it is that causes it, it's extremely annoying.
I got a large enough chunk in my eye once that I decided I needed to do something about it. Seeing that I didn't have any sun glasses at the time either, I picked up a pair of the largest aviator frames I could find, then had prescription sunglasses made out of them. They don't exactly provide the kind of side protection that dedicated safety glasses would, but the lenses are still big enough that at least all head on projectiles are blocked, which means I still have to be careful who I to the left of at the range. They do look really cool however, and I can use them outside of the range as well. Not too bad of a compromise I suppose.