What kind of prescription glasses do you wear right now? If it's wire frame, the wind could simply be passing through at the bridge. I use ugly (some would say "contraceptive) American Optic plastic frames with a "keyhole" bridge--pretty tight around and over the nose, lenses don't quite touch my cheeks when I'm cheshire grinning, and they do a great job keeping my eyes from tearing, even without being wraparound. My own glasses while riding theory is that it's more important to keep the wind from coming through the front of the glasses than worry about wind at the side of the glasses where wraparound designs would help. Most wraparound designs are too short to keep wind from slipping up underneath them, between them and your cheeks.

Obviously I've put way too much thought into this, but such is life when your wife (now ex-) is an optometric technician...