When were clip on sunglasses invented?

I don't know when they were originally invented. But they were so to say re-invented 2007 by http://www.sunclipies.com . They invented a clip-in system,where thin-film lenses are clipped into the glasses from behind. The advantage is it is super light weight and they don't change the look of the eyeglasses, but just the lens colors. They are exactly tailored to each pair of eyeglasses, using rapid manufacturing technology.