Bothersome reflections
A bright source in a low-light situation, such as headlights at night, or a TV in a dark room, will result in ‘ghost images’.
Back surface reflections from sunglasses, since the sunglass lens is transmitting 10-20% of the ambient light and the rear surface reflection is 4-6% of the ambient light, will result in an easily seen magnified image. For myopes the reflection may be in focus, for hyperopes it will be a distracting ‘haze’.
Edge reflections in high-minus Rx’s where the edges have been polished can be very distracting to the wearer.