mercoledì 6 gennaio 2016

# s-eye: the myopia boom: an environmental effect

<< East Asia has been gripped by an unprecedented rise in myopia, also known as short-sightedness. Sixty years ago, 10–20% of the Chinese population was short-sighted. Today, up to 90% of teenagers and young adults are. In Seoul, a whopping 96.5% of 19-year-old men are short-sighted >>

<< children need to spend around three hours per day under light levels of at least 10,000 lux to be protected against myopia. This is about the level experienced by someone under a shady tree, wearing sunglasses, on a bright summer day. (An overcast day can provide less than 10,000 lux and a well-lit office or classroom is usually no more than 500 lux.) >>

<< But what scientists really needed was a mechanism: something to explain how bright light could prevent myopia. The leading hypothesis is that light stimulates the release of dopamine in the retina, and this neurotransmitter in turn blocks the elongation of the eye during development >>

Elie Dolgin. The myopia boom
Short-sightedness is reaching epidemic proportions. Some scientists think they have found a reason why. Nature 519, 276–278 (19 March 2015) doi:10.1038/519276a

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