Eye creams are formulated specifically for the delicate skin around the eye, so they tend to be thicker. They contain more oil than a regular facial lotion, and they have a lot of active ingredients aimed at the problems we see around the eyes.
Puffiness is a buildup of fluid and blood under the eyes. Some studies show that caffeine can help circulation, which could reduce puffiness. Other studies show that cold temperatures are just as effective to treat puffiness. That's why some people refrigerate their eye creams.
Dark circles under the eyes come from genes, sun damage, age, and blood build-up. Sodium ascorbate, or vitamin C, can thicken the skin and help conceal dark circles after about 6 months. Niacinamide, or vitamin B3, and kojic acid can lighten dark circles.