I suggest you measure carefully before buying a pair of these clip-on sunglasses.  My glasses are bifocals and a bit on the wide side, and I almost ordered the wrong design.  These overlap my lenses only slightly, something not at all noticeable to others.  On the other hand, if they were too short it would be readily apparent and they would look a little goofy.

They do a great job of providing shade...the fact that they are polarized makes a big difference.  My son pointed this out to me as we were riding in the car one sunny day.  For example, with polarized lenses, the reflections on the windshield of items on the dashboard disappear.  I did a direct comparison with a pair of non-polarized sunglasses and the difference was significant.

They are thick, well made, high quality, and attach easily.  Their being thick, however, brings me to their main drawback...they are a bit on the heavy side and this can make them somewhat uncomfortable to wear after an extended period of time.

The only other negative is that when you flip them up, they really don't flip up far enough.  I found myself having to tilt my head quite a bit to look at grocery store items when I walked out of the sun and into Winn Dixie.

So, minus one star for the weight and the flip factor.

Overall, though, I highly recommend them...I would buy them again without hesitation.