Sunscreens were first used in1928 and became popular with those intentionally trying to gain a suntan. They mainly filter out the wavelengths responsible for sunburn (UVB, 280-315 nm). Following evidence that longer wavelengths of sunlight (UVA, 315-400 nm) are involved in the sunburn reaction and photocarcinogenesis, UVA absorbers have been added to most sunscreens to widen their absorption spectra. There is concordant evidence that sunscreens undoubtedly protect against sunburn, but evidence for a role in the prevention of skin cancers is still somewhat equivocal.1,2 The concept of a sunscreen effectiveness index (ratio) is attributed to Schulze and Greiter, who proposed the specific term "sun protection factor" (SPF), and the associated method for assessing SPF.3 SPF activity is the ratio of the least amount of UV energy required to produce erythema (reddening of the skin) on sunscreen-protected skin to the amount of energy to produce the same effect on unprotected skin.
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Rosacea and Eczema are two skin conditions that are fairly commonly found throughout the world. Each of them is characterized by different features, and can be both discomfiting as well as result in undesirable appearance features. In a nutshell, theyre problems that many would want to deal with.