Ultraviolet radiation and visible light both have biologic effects on the skin. Visible light can induce erythema in light-skinned individuals and pigmentation in dark-skinned individuals. Broad-spectrum sunscreens protect against ultraviolet radiation but do not adequately protect against visible light. For a sunscreen to protect against visible light, it must be visible on the skin. Inorganic filters (also known as mineral filters), namely, zinc oxide and titanium dioxide, are used in the form of nanoparticles in sunscreens to minimize the chalky and white appearance on the skin; as such, they do not protect against visible light. Tinted sunscreens use different formulations and concentrations of iron oxides and pigmentary titanium dioxide to provide protection against visible light. Many shades of tinted sunscreens are available by combining different amounts of iron oxides and pigmentary titanium dioxide to cater to all skin phototypes. Therefore, tinted sunscreens are beneficial for patients with visible light-induced photodermatoses and those with hyperpigmentation disorders such as melasma and postinflammatory hyperpigmentation.
Keywords: iron oxide; photoprotection; tinted sunscreen; titanium dioxide; ultraviolet light; visible light.
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