‘I don’t want to be 20 cent’ –50 cent


Between the 1970s and the early aughts, the incidence of myopia in the US nearly doubled, to 42 percent. Myopia’s rise has been the starkest in Asia; one survey in Korea found a rate as high as 96 percent among teenagers.

Clearly, something is going on. But scientists can’t agree on exactly what. Being constantly tethered to devices and books indoors might be part of it: Based on a handful of large epidemiological studies on myopia, spending time outdoors—especially in early childhood—reduces the onset of myopia. […]

Neuroscientists discovered the classic animal model for myopia by accident in the 1970s, when they were sewing one eye shut in newborn monkeys to study the development of the brain’s visual system. […] Around the same time as the eye-sewing experiments, neuroscientists figured out they could do the same in chickens and tree shrews—much easier to keep in the lab than monkeys. And instead of sewing the eyelid shut, they could just put what looks like half a ping pong ball over the eye. This “form deprivation” model of myopia has inspired some fascinating science. In 2010, for example, Morgan’s collaborators found that exposure to bright light could reverse this type of induced myopia in chickens. Further experiments pinned down the mechanism, too: Light activates the neurotransmitter dopamine, which prevents the eyes from growing longer.

{ Wired | Continue reading }