Dec. 16, 2009 -- Don't look now, but you could be, right at this instant, contributing to a growing problem in America: nearsightedness.
A new study conducted by the National Eye Institute shows that the rate of nearsightedness, or myopia, in Americans has increased from 25 percent in the 1970s to a staggering 41 percent this year.
The study didn't examine the causes of such an increase, but experts told "Good Morning America" the reasons could include genetics or poor outdoor lighting. Another possible reason could be an increase in "near work"-like reading, surfing the Web or texting.
"Nearsightedness work can really affect the development of young eyes," said Dr. Roy Chuck, chairman of ophthalmology at Montefoire Medical Center in New York. "If that is exclusively the kind of work that you are doing, it is equally important to be outside playing, stimulating your far vision."
Though the study's author, Susan Vitale of the National Eye Institute, said more research is necessary, she added that identifying the problem was important.
"It was really good to be able to confirm this was going on," Vitale said. "While myopia is pretty easily treated, when a lot of people -- 40 or 50 million people -- it ends up costing the U.S. about $2 to $3 billion annually. So it's an important problem if it's on the increase."
Dr. Richard Besser, ABC News' Senior Health and Medical Editor, said myopia is genetic.
"If your parents were nearsighted there is a good change that you're going to develop nearsightedness," Besser said.
National Eye Institute to Dedicate More Money to Research
"I was very nearsighted as a child. Maybe that is why I spent a lot of time reading and doing indoor activities. Maybe my nearsightedness wasn't caused by that but that you tend to go to things that play to your strengths," Besser said.
According to Vitale, the best thing people can do to help balance near-sightedness, other than "outside playing," is to get the recommended eye care exams and get treatment if necessary.
The National Eye Institute plans to dedicate $110 million dollars to future studies, including what caused the rise in myopia, Besser said.