ultraviolet light (redirected from UV-A)

Ultraviolet (UV) light

A portion of the light spectrum not visible to the eye. Two bands of the UV spectrum, UVA and UVB, are used to treat psoriasis and other skin diseases.

Mentioned in: Eye Glasses and Contact Lenses, Ultraviolet Light Treatment

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ultraviolet light,

n light beyond the range of human vision, at the short end of the spectrum. It occurs naturally in sunlight; it burns and tans the skin and converts precursors in the skin to vitamin D. It is used in the treatment of psoriasis and other skin conditions. Prolonged or excessive exposure to ultraviolet light can damage the skin and increase the susceptibility of the skin to cancer.

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ultraviolet light

Ultraviolet radiation Physics The part of the invisible electromagnetic spectrum below violet, including photons emitted during electronic transition states Wavelength 100-400 nm Public health The electromagnetic spectrum between 200 nm and 400 nm which is emitted by the sun. See SPF, Sunscreen.

UV light types

UV-A Long wave, 'near' UV, black light; short wave UV-A–320–340 nm; long wave UV-A–340–400 nm; no UV-A absorbed by ozone layer

UV-B Middle UV, sunburn radiation UV-B–290–320 nm; most UV-B is absorbed by ozone layer

UV-C Short wave, far UV, germicidal radiation, ≤ 290 nm; absorbed by ozone layer; has no role in photobiology of natural sunlight

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Patient discussion about UV-A.

Q. what does a sun block cream do? and what are a UV rays?

A. It blocks out harmful Ultra violet rays from the skin as the previous entries have related; however it can also block your ability to produce vitamin D. If you live in a northerly area or one that receives limited sunlight, its recommended to get at least 15 minutes of sun a day (this is probably best done with minimal sunblock) and according to personnal sun sensitivity. Another thing to keep in mind is that sunblock works best if applied 20 minutes before sun exposure.