Lens will come apart/break by top screw eventually. I've owned 3 pairs of these and the lens always breaks there after about 8-12 months. They replaced them all but it's is not free to do this even under warranty. Charge a service fee and you have to ship back. I've owned ray bans that this never happen to. Just a pain to keep returning for repair. You have to be VERY careful when you clean them They are very fragile where the lens and screw are drilled in. They are light weight and that probably contributes to the breaking issue. Clean them very very gentle or in time they will break!  Your might be broken already and its just hasn't slipped out yet.  The screw will still hold the lenses in.