Sun damage is responsible for up to 90% of the visible signs of premature aging on the human face, including unwanted wrinkles. We all know that the sun can alter our appearance by causing our skin to burn or tan, but we now know that much of what we considered to be a natural aging process is actually the result of long-term exposure to sunlight. Sun exposure causes damage in the form of photoaging.
The term photoaging describes the microscopic alterations that result from continuous exposure to sunlight, especially UVA radiation. Cumulative exposure to the sun imparts damage to the epidermis (the outer layer) and the dermis (the deeper layer where the skin’s framework resides). The most striking features of photoaging are seen in the dermis, where virtually all of the skin’s structural components are altered. The elastic fibers are thickened and become more numerous. Collagen is damaged and degraded, and “reticulin” fibers appear throughout the dermis rather than outlining the specific dermal-epidermal junction.
In addition to wrinkling, visible blood vessels, skin roughness, pigmentation changes, and skin discoloration, the long-term consequences of photoaging include dramatic loss of skin elasticity and thinning of the skin. This is the result of ultraviolet radiation’s direct effect on the collagen matrix. The collagen matrix of the dermis is the ‘scaffolding’ that gives firmness and strength to the skin, but when exposed to ultraviolet radiation the collagen folds on itself, and as this happens, the skin thins, and wrinkles and furrows appear.
For a long time we believed that photoaged skin was irreversibly damaged, but it has now been shown to undergo significant repair when ultraviolet exposure is stopped. This important discovery proves that our skin does have the ability to repair itself from the sun’s harmful damaging effects and that sun protections plays an important role in that process. Proper use of sunscreen helps prevent photoaging while simultaneously allowing the skin to restore itself, or as clinical and research dermatologist Zoe Diana Draelos, M.D. stated it in the Janurary/Feburary 2007 issue of Aesthetic Dermatology News, “Sunscreens are the most effective anti-aging ingredient on the market today.”