Study shows Chinese students in poorer area have better vision
What if living in a middle-class neighborhood meant increasing your chances of being nearsighted?
That's what a study of 20,000 students in China seems to suggest. Researchers found that nearly 25 percent of students in the middle-income province of Shaanxi were nearsighted – a prevalence rate that is twice as high as the poorer area of nearby Gansu.
Researchers remain puzzled about the reasons why. But with myopia hitting historically high levels in Asia and across the world, scientists are continuing to probe for potential causes.
In the United States, the prevalence of myopia has shot up from 25 percent in the 1970s to more than 40 percent today. In developed cities and countries in Asia – including Shanghai, Taiwan and Singapore – roughly 80 to 90 percent of people are nearsighted. The Asian countryside is no safe haven from myopia, either: while rates of nearsightedness are lower, only 1 in 6 rural Chinese children have the eyeglasses they need.
"It's a big deal," said researcher Nathan Congdon, M.D., MPH, of the Zhongshan Ophthalmic Center at Sun Yat-sen University in Guangzhou, China. "It's obviously much harder to learn at school if you can't see."
Learn more about myopia
Dr. Congdon's research paper, one of the largest Asian studies of nearsightedness in children, was published online in the journal Ophthalmology in early 2015. Among the findings, scientists discovered that living in the middle-income area was associated with a 69 percent increased risk for nearsightedness. Higher math scores were also associated with increased myopia regardless of where they lived, while males had lower rates of nearsightedness overall.
Other studies have linked the level of education and years in school to nearsightedness. On the flip side, exposure to outdoor light may help protect young eyes from myopia, according to recent research.
"What's important is that we figure out how lower-income Chinese students have avoided nearsightedness so we can use those same strategies to prevent more childhood myopia cases across Asia and perhaps even the world," Dr. Congdon said.
How being outdoors may benefit children's eyesight