Botox can be used for treating wrinkles on the lower eyelids as well as the crow's feet creases on the outside of the eyes. How much Botox is needed depends on how many crow's feet creases you have. If you're young and have only a couple of crow's feet creases on either side, you may need only 4 units for both sides together. However, for older patients who have developed more wrinkles involving a larger area, more Botox can be necessary. At a certain point, when the crow's feet creases run into parallel cheek creases, it's best not to use Botox for crow's feet creases without combining it with laser resurfacing of the face. The only way to know how much Botox you need is to consult with a board-certified cosmetic dermatologist or plastic surgeon.