MadSci Network: Medicine |
It does not matter what the source of UV light is (whether it is from the sun or manmade). All forms of UV light can be harmful to the eyes and skin. (You asked specifically about eyes, however, a lot of damage is done to the skin, so I included damage to the skin as well in my answer.) As you mention, UV light is divided by wavelength into three groups, UV-A, UV-B and UV-C. UV-C light is the most dangerous, but it is filtered out by the atmosphere. Because of this, it will not be discussed further. UV-B light does not penetrate into deeply into the skin, but can cause skin cancer. This light is partly filtered out by the atmosphere. UV-A light penetrates more deeply than UV-B and causes damage to the skin and the connective tissues supporting the skin. This light also causes sun tans and sun burns. All of these forms of UV light can cause skin cancer, wrinkling and aging of the skin. In addition, UV light cause cataracts, which is a clouding of the lenses of the eyes which requires artifical lens implanted during surgery. THis is such a big problem that cataract surgery is the mostc common surgery of the elderly in the US. It can also cause macular degeneration, which is the most common form of blindness in those over 50 years of age. IN addition to sun exposure during the summer, sun exposure during the winter can be damaging as well. For example, the UV light reflected by sun can cause a really bad sunburn. This is true for the light reflected by the beach and water in the summer as well. You did not mention a specific way UV light is made by man. There are special UV lights that are used in medicine, for example, to see fungal infections on the skin or scratches on the surface of the eyes. However, these lights are not of the right type to really damage the eyes during the short duration that the eyes are exposed to the light. However, other sources of UV light can be damaging to the eyes. One is the UV light that is made when someone is arc welding. This light can cause a burn to the surface of the eye, cuasing damage similar to a sunburn of the eye. Other sources of information including from the Centers for Disease Control and Prevention (for skin cancer, mostly; http://www.cdc.gov/ChooseYourCover/uvrays.htm) and from the American Acadamy of Opthamology (eye stuff; http://www.eyenet.org/public/faqs/uv_faq.html)
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