My comment was based on personal observation, and on what my eye doctors have said (presumably based on their own anecdotal experience).
I have added some more links, which also seem to indicate the same association. The last one, showing a relation with time spent outdoors, is perhaps the closest to being on the right track. But this needs more research.
Accommodation and Near WorkComparisons between myopia rates in 1882 and 1964 showed that the rate is very different for individual professions68 (students in the 30% range, unskilled workers in the 2 to 3% range): While the total rate of myopia was increasing, the myopia rate for all the individual professions except unskilled work was decreasing. Explanation: The overall increase in myopia, according to these results, can be largely attributed to a changed ratio of job distributions from unskilled work towards professional and office work.
Highly elevated rates of myopia were found for craftspeople of various professions, who have to do extensive near work, e.g. for typesetters (in year 1930117), tailoring (in the years 1953118 and 1961119). Up to 77% of the persons in these professions were found to be myopic.
Role of Near Work in Myopia: Findings in a Sample of Australian School ChildrenBecause of the association of myopia with educational performance and close-work occupations, near work has long been considered an environmental risk factor for the development of myopia. Among the various pillars of supporting evidence that link myopia to education and near work are the higher myopia prevalence rates that paralleled the introduction of schooling in Eskimo populations, the higher prevalence of myopia in orthodox Jewish boys who undertook intense schooling compared with that in orthodox girls or boys and girls in general schools, and the presence of myopia among Chinese fishermen who reported reading in childhood.
An NPR report"If you have two nearsighted parents and you engage in a low level of outdoor activity, your chances of becoming myopic by the eighth grade are about 60 percent," he says. "If children engaged in over 14 hours per week of outdoor activity, their chances of becoming nearsighted were now only about 20 percent. So it was quite a dramatic reduction in the risk of becoming myopic."
At first, that seems to support the theory that near-work causes nearsightedness: The more time kids spend indoors, the more likely they're watching TV or reading a book.
But then Mutti and his colleagues looked closely at the kids before they became nearsighted. And the reading and close-up things they did didn't predict who'd be nearsighted later. "What we found is that near-work had no influence at all," he says. "Children really aren't doing any more or less near-work the children who are becoming nearsighted."
So that's another mystery. Why, then, does spending time outdoors make a difference? At first, scientists thought the outdoor exercise was the key. But it turned out kids who get indoor exercise don't get the benefits of reduced myopia.
Now, researchers are studying whether outdoor light somehow changes the way the eye grows.
™ Version 4.2
