Does what it needs to do
I was looking for reading sunglasses for a vacation to Mexico.  There seem to be the ~$15 dollar versions and the ~$150+ versions with very little in between.  My sunglass of choice is the RayBan Aviator.  These stick-on lenses let me keep my preferred style AND be able to read by the pool.  They were easy to stick to the RayBan lens (which is glass and spherical), and I have had no problems with the stick-on detaching in two months of use, even in the humid Mexican summer or while splashing in the pool.  The users who have had problems seem to be dealing with plastic lenses or high curvatures.  For the money, these lenses do what they need to do.
Rating: 4 stars