I have a pair of Bolero sunglasses that I just love. They are perfect for driving as well just when you are in bright sun, and yesterday, while walking along Dartmouth Street in front of Douzo Japanese restaurant, I dropped them on the floor. One of the lenses just popped out. While I did not pay for them because they were a gift, I felt awful and started to wonder if I had lost them forever or if there was a way to fix them. So when I got back home I took a magnifying glass and noticed that instead of being glued to the frame, they were actually snapped in (which kind of makes sense because the lens just popped out, something that was unlikely if they were glued). Don't try this if your glasses are really expensive and also don't really push it too hard and definitely do not attempt this if you are not an engineer by training like me, but if you position them from the inside at the lower end of the frame and then stretch the frame just a bit to accommodate the top portion, the lens should snap right in. I am not sure but maybe if you call a few shops that actually make eyeglasses they might be able to get it fixed for you.
My Life In Bits And Pieces in Massachusetts.