What is the best treatment for static lines under eyes and static crows feet on one side of the face? (Photo)

The lines under my eyes began to develop at age 19, I'm now 23, not much has changed, except for those crows feet lines present only at the left side of my face. When I smile I don't have any wrinkles, nor do the lines I have worsen, it's when my face is at rest that they show. I use sunscreen religiously and avoid smoking, don't know why I have those lines. Also, should I start OTC retinol or prescription Retin-A?