Word: sclera
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Dates: during 1980-1989
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...study has conclusively settled the origins of myopia, nor how much heredity or eye-strain is to blame. "Myopia has been associated with everthing from pregnancy to tooth decay," Greene says. Researchers agree only that myopia is the abnormal bulging of the back of the eye or "posterior sclera," usually around the gap for the optic nerve. But no one is sure what causes the swelling, whether myopics are born with bulge or have brought it on themselves by reading in dark corners...
...McMahon and Greene set to work building a mechanical eye. The model immediately provided two insights. First, strain occurs when the two oblique muscles--the muscles in the back of the eye which control its rotation--are tensed greatly, as in reading. The tension stretches and strains the sclera. Though such stretching is normally elastic, if it is both frequent and extreme enough the sclera does not return to its normal position and myopia develops. Second, the eye is least able to reduce strain near the point where the optic nerve enters the eye--Greene draws an analogy with...