All skin is subject to damage from harmful conditions. These include everything from the ultraviolet rays of the sun to dry air, atmospheric pollution, wind and temperature – even problems with diet, sleep and stress. The effect of any of these conditions is multiplied and magnified in the thin, delicate skin of the eye zone, making it most likely to show signs of stress and age. Collagen and elastin cells, which provide the structure that makes skin firm, smooth and supple, are thin and close to the surface, where ultraviolet light, in particular, can weaken them. This can cause lines and wrinkles to form, discoloration, sagging skin and puffiness. The tiny blood capillaries are close to the surface, so that any changes can immediately show additional darkening of the skin. This darkness is often referred to as dark circles.