It is comprised of four layers. In cases of aging or sun damage, the outermost layer is thickened, becoming dry, rough and dull. Ultraviolet light encourages excess melanin production in the innermost layer causing age spots and unwanted pigmentation. The dermis is mostly collagen, the connective tissue that give skin its strength and elasticity. Collagen is in two layers, the upper papillary dermis and the deeper reticular dermis.
Ultraviolet light ages the collagen and destroys the elasticity of the dermis.
This is the cause of lines, wrinkles, thinning and sagging. As collagen disappears, spider veins appear. When it strikes the skin in cosmetic surgery, it is absorbed by the water of the skin. It heats tissue to a depth determined by the absorption length. The controlled wavelength of the cosmetic Ultra Pulse Laser is rapidly absorbed and does not penetrate the skin deeply.