Photo-aging is the premature aging of your skin caused due to the prolonged exposure to ultra violet rays of the sun. This is caused as a result of the damaging result of the UV rays which alter the normal structure of your skin. When the UV rays affect your skin it causes the dermal cells to produce melanin. When there is increased production of melanin makes your skin tan. The Ultra Violet Rays are made up of two different types of waves, which are the UVA and the UVB. UVB rays are responsible for causing sunburns, while the UVA rays cause maximum photo-aging damage. The UVA rays penetrate deep in to the dermis and cause damage to the collagen fibers. An increased production of abnormal elastin and enzymes called metalloproteinases which rebuild the damaged collagen as a result of the damage. Overtime these enzymes malfunction and breakdowns the collagen which results in improperly repaired skin. When this continues to happen the skin starts to form wrinkles, and the collagen eventually depletes resulting in leathery skin. When your skin is repeatedly exposed to sunlight, it also forms what is known as the age spot.