Originally Posted by
unterhausen
I have to say that nobody I know uses a mirror on their glasses, the almost all use helmet mirrors with the occasional mirror on the handlebar
Opposite here. Almost all that use mirrors use eyeglass mounted mirrors, or mirrors fixed to the bike. Helmets move, shift and bounce much more than glasses.
Personally, I find bike mounted mirrors nearly useless compared to to eyeglass (or helmet) mounted mirrors due to either very narrow field of view or demagnification and vibration. Eyeglass mounting provides a much wider, full scale, steady and steerable view. Helmet mounting is nearly as good.