Compare these sunglasses to the popular Versace Sunglasses line.  These smooth rounded sunglasses are extremely popular in the fashion industry and amongst celebrities.  The plastic frame allows them to be light and flexible.

 

 

 

 

These tend to look exceptionally well on people with square/rigid or oblong face shapes.  Reduce the angles with soft, curvy styles that will give the face some definition.  For oblong faces these will help to widen and shorten the face.