Recent research suggests that more outdoor activity can reduce the risk of myopia, perhaps because outdoor daylight is stronger, the field of view is wider, and the afterglow is more consistent with the distance from the observer. Closer and closer “close work” may be another way to change human behavior that doesn’t mesh well. Our ancestors did not read, and even those who sharpened arrows or did other fine work probably did not do it all day, every day. Frequent proximity work came with the advent of modern civilization. In many countries and regions, this dates back to the last century or the last century. Many people become nearsighted in childhood, and I’m afraid the classic image of the nerd with a “bottle-bottom” frame is somewhat justified. However, myopia can also occur in adulthood, and myopia rates are extremely high among textile workers and those who work with microscopes all day, and it has become an occupational disease. A recent study by Xinmei Su et al. has linked “reduced outdoor activity/increased close work” to myopia. “Reading, writing and operating a computer are all associated with myopia,” she said, “and we found that children who spend a lot of time on the computer are more likely to be myopic.” Guggenheim also found that myopia was higher among teenagers who liked to read. Another team surveyed Danish medical students and found that those who were absorbed in reading a lot of boring books were also more likely to be myopic. Murty and Morgan’s study found that close work hardly damaged vision, and since then the “close work causes myopia” hypothesis has lost a group of fans. In fact, it is easy to organize the potential factors that cause myopia: people who read a lot of books probably read them indoors, and so does watching TV or using a computer. In 2007, a survey done on medical students in Turkey further shook up the near work theory. Compared to their classmates with excellent vision, those medical students with myopia spent less time outdoors before the age of 7. Of those myopic medical students, about 1 in 7 were myopic after age 18. The researchers did not find any differences in their close work, as every medical student does a lot of close work such as reading. However, the findings suggest that the “ill effects” of too little outdoor activity may not become apparent until they are older. Other studies suggest that some of the lesser noticed factors are also at play. One study found that physical activity appeared to have some preventive effect on myopia in 11-year-olds. This trend was also observed in Danish medical students. Muti wondered if the positive effect of staying outdoors on preventing myopia was related to vitamin D. After all, humans rely on ultraviolet light to synthesize this vitamin. In a small study of his own, the adolescents who were the subjects spent roughly equal amounts of time outdoors, but the myopic patients did have 20 percent lower vitamin D levels than those who were not myopic, after accounting for age differences and differences in dietary structure. Culture clash Although these theories are still being investigated, some scientists are already calling for action. Steele says, “We have to let parents know that kicking also kicks the kids out the door.” Morgan agrees, but says that in some countries where myopia rates are already climbing, the look-at-your-sons mentality can block the path. “Just look at the academic life of Chinese kids, and you’d be shocked at how airtight it is,” Morgan said. At school, kids have an hour or two to stay indoors after lunch for a lunch break, then continue studying for a few hours. This pattern is difficult to change, he said, “I’ve suggested eliminating lunch breaks for Chinese kids, and they react as if I’m proposing child abuse.” Western countries also have children who study hard, “but when you see Chinese children, they really don’t count for much. Even so, Su Xinmei said, it may be easier to get children outside than to reduce their close workload. The Asian education system has reached a “saturation point” in terms of intensity and competitiveness, she says, “but you can’t make kids study less and learn less; it’s not politically correct. In the U.S., the clinical medical community has had mixed reactions to the new data. Jane Gwiazda, a psychologist at the New England College of Optometry, said that although ophthalmologists are beginning to understand the outdoor light theory, children usually don’t see an ophthalmologist until after they have problems with their eyes. Pediatricians can get ahead of that, she says, by encouraging children to get outside more often, “once they’re nearsighted, it doesn’t help to send them outside again. If you can’t get out, looking outside more often may help. Doing so doesn’t seem to affect baseball star Hornsby’s eyesight. Someone once asked him what he does in the winter when there are no games. Hornsby replied, “I just keep staring out the window and wait for spring to come.”