ABSTRACT
Visible sunlight is only a tiny part of the whole radiation spectrum emitted by the sun (400-700 nm). By increasing wavelength greater than 700 nm, one enters the invisible radiation range called infrared radiation (IRR); by decreasing wavelength lesser than 400 nm, one enters the ultraviolet radiation (UVR) domain. Overexposure to the sun’s invisible rays can be harmful to human skin. The damage can be immediate with visible effects, such as erythema and sunburn, leading to cell and tissue degradation. The damage can also be long term, and the cumulative effects of prolonged exposure are now increasingly recognized to be the possible cause of degenerative changes in the skin such as premature wrinkling and skin cancer. Indeed, many skin changes that often are identified with aging actually result from damage by too much sun exposure (1,2).
