There's no way to have your straps against your face for many types of helmets (Specialized, Giro) if your glasses are inside your straps.

My straps are tight enough that they actually bend in the arms of my glasses if I tried that.

I don't understand how your glasses could fall off in either case. The first thing I do when I try on a pair of glasses is bend over and see if they move. It's my first criteria.