These vintage shades are a real period piece, the kind of sunglasses that you would expect to see Jean Claude Killy wearing.  I'm guessing that they were introduced for the 1976 Olympics, in that they look quite similar to what Ray Ban was doing at the time.   The color scheme is very seventies as well, people were dressing rather boldly back then. The mirrored lenses said "I can see you, but you can't see me!", but at least they could see a reflection of themselves.