Aging, or if you love laughing, look in the mirror and you might find these etched wrinkles that begin at the outer corner of the eye area and fan out. Unlike fine lines, which tend to get smoother and respond well to superbly formulated moisturizers, crow's feet are much less responsive.
Of particular note when it comes to ingredients are peptides and retinol. The best way to reduce crow's feet has always been applying a peptide- or retinol-rich serum first, and then a great eye cream. They partner with other components of skin to visibly improve the appearance of fine lines, wrinkles, and dullness.