Injectable fillers can be used to reduce the appearance of lines at the corners of the eyes, commonly known as crow's feet.
But, there's a catch... It is best to first use Botox in that area to minimize the muscle contractions which are causing the skin to bunch up when you smile, thereby forming "crow's feet". Then, after a week or two, if any pesky lines are still visible after Botox has relaxed those muscles, then an injectable filler such as Restylane can be used to further conceal the crow's feet if they still bother you.
If you just use a filler without Botox, the filler will dissipate quickly because the muscle contractions will cause it to break down and you'll be disappointed that the results did not last longer.
Laser resurfacing or a chemical peel will also help retexture the skin to smooth away lines that are visbile even when you are not smiling.