Cutting time outdoors in the sun and spending more time indoors on books, video games and TV may be contributing to the “extraordinary rise” in East Asian teenagers suffering from myopia or short-sightedness, according to a new study.

Short-sightedness has been described as a “major health issue in east Asia,” according to scientists who found that up to 90 percent of high school graduates are suffering from myopia in cities in China, Japan and South Korea.

Researchers are concerned because 10 to 20 percent of the myopia patients are reported to have “high” myopia, which can potentially lead to blindness.

The study, published in The Lancet medical journal, found a strong association between the increasingly high prevalence of myopia in the past few decades with increasing educational pressures, combined with life-style changes, which have reduced the time children spend outside, researchers wrote.

"East Asian countries with high myopia now dominate international rankings of educational performance," researchers added.

Lead author Ian Morgan, a professor at the Australian National University in Canberra, recommend that research should focus on preventing the progression of normal short-sightedness to high myopia, and that people should be educated of the potential for loss of vision and blindness of the eye disease so they can seek immediate treatment.

“It poses a major challenge to ensure that all the kids who need glasses or contact lenses get them,” Morgan said, according to Bloomberg.

"Even if successful prevention is possible, East Asia will still be faced, for close to the next 100 years, with an adult population at high risk of developing high myopia," the researchers wrote.

"Further progress in our understanding of the natural history of high myopia is thus essential, and while there have been some promising developments in treatment, more effective treatments are still required," they added.