Researchers have discovered that the ultraviolet (UV) light that causes the temporary but painful condition of snow blindness in humans is life-saving for reindeer in the arctic. A Biotechnology and Biological Sciences Research Council (BBSRC)-funded team at University College London and other institutions published a paper in the June 15, 2011 issue of the Journal of Experimental Biology that shows that this remarkable visual ability is part of the reindeer's unique adaptation to the extreme arctic environment where they live. It allows them to take in live-saving information in conditions where normal mammalian vision would make them vulnerable to starvation, predators, and territorial conflict. It also raises the question of how reindeer protect their eyes from being damaged by UV, which is thought to be harmful to human vision. The paper served as the cover story for the Journal of Experimental Biology issue. Lead researcher Professor Glen Jeffery said "We discovered that reindeer can not only see ultraviolet light, but they can also make sense of the image to find food and stay safe. Humans and almost all other mammals could never do this as our lenses just don't let UV through into the eye. "In conditions where there is a lot of UV – when surrounded by snow, for example – it can be damaging to our eyes. In the process of blocking UV light from reaching the retina, our cornea and lens absorb its damaging energy and can be temporarily burned. The front of the eye becomes cloudy and so we call this snow blindness.
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