These did fit my Prada glasses perfectly though the lenses were not quite as thick as the originals.  Time will tell if they hold up as far as scratch resistance and other aspects.  I wasn't quite sure how to replace these at first -- the instructions I had talked about two kinds of glasses: plastic frames where the lens pops out and then they talked about metal frames that come apart.  Well, mine are metal frames but I couldn't see any way for them to come apart.  Took out some screws and the earpiece on one side trying to figure it out and to me it seems that my frames are solid.  So I ended up just REALLY carefully popping out the old lenses and popping in the new.