Crow's feet are lines around the outside of the eyes created by relation of the orbiculares occuli which closes the eyes, and aging of the skin.  Unless the lines are very deep and have been apparent for many years they are best treated by Botox injections.  I use 25 units around the lateral aspect of each eye. 

Occasionally lines get so deep that Botox alone will not solve the problem.  In this case Botox plus a filler such as Juvederm or any of the hyaluronic acid fillers usually solves the problem.  After this only surgery will help.,