Crow’s feet are the wrinkles around your eyes caused by the contraction of the muscles surrounding your eyes (orbicularis oculi).
This muscle is attached to the skin, so when you make repetitive facial expressions, such as smiling or squinting you pull the skin around your eyes and create wrinkles.
This continual movement is what causes other wrinkles such as frown lines, eye wrinkles, laugh lines, smile lines, facial lines, and facial wrinkles.