A friend was wearing a pair of these over her prescription glasses, and I couldn't tell she had on both pair.  Tried them for fit over my own glasses and was amazed that they fit well with or without my glasses.  I liked my friend's black pair, but opted for the burgundy for something a little different.  Have since found that they are great in foggy conditions. And unlike the custom fit clip-ons for my prescription glasses, when going into a tunnel or reduced light I can see my dashboard clearly. They are comfortable to wear during long travel behind the wheel. Plus they fit over either of my glass frame sizes. Just follow the instructions and measure your frames (in mm's) to be sure they'll fit before ordering.  These are the highest quality lenses I've had in sunglasses, and the price is very reasonable. I highly recommend them.