Abstract

Skin aging is a complex process and can be divided into two basic processes: intrinsic aging and photoaging. The term “photoaging” was first coined in 1986 and described the effects of chronic ultraviolet (UV) light exposure on skin (Kligman and Kligman 1986). “Photo” is derived from the Greek word “phos,” which means “light.” Photoaging is premature aging of the skin caused by cumulative exposure to UV radiation (UVR) from the sun and artificial UV sources.