Once you get these clip-ons in place, they work just fine.....They are big enough to cover almost any size glasses, but not so big that they rub against the cheekbone. One big problem though: The two halves of the clips are relatively stiff and almost exactly the same length. That may not seem important, but it makes it maddeningly difficult to install the these clip-ons on your glasses....so I wouldn't recommend them. I wish some product designers would think things through more carefully.