According to the Journal of Ophthalmology, by the year 2050, 5 billion people will have myopia or nearsightedness.
Myopia is the most common refractive error of the eye. Being nearsighted means that people have trouble seeing things far away, like road signs or distant objects, but can see things up close, like words on a page, in focus.
It occurs when the eyeball is too long, causing light rays to focus at a point in front of the retina, rather than directly on the surface.
Part of the problem could be what some call a "screen-obsessed" culture - too much time spent looking at screens, which could affect vision. And the problem might have more impact on children, whose vision is still developing.
But a researcher at the University of Washington has developed glasses that may help counteract the problem of excessive eye growth, which leads to myopia.
Twelve-year-old Olivia Kwan has worn glasses since first grade.
"I couldn't even see things that my friends -- even though they had glasses -- could see," Kwan said.
Both her parents have myopia and knew Olivia's eyes would get worse. Myopia typically begins in childhood and a person can have a higher risk for it if both their parents are nearsighted.
So Olivia's parents were interested in getting her to participate in a new trial for glasses aimed at slowing or stopping the progression of myopia.
"If there was an opportunity to help her either sort of slow down or stop her myopia and also contribute to the medical field to help other kids, I was all for that," Jen Chan, Olivia's Mom, said.
Dr. Jay Neitz is a professor in the Department of Ophthalmology at University of Washington. He explained that as kids grow, their eyes ideally lengthen until they have perfect vision. But too much time spent in front of a screen confuses the eye, since everything is in focus.
The eye keeps growing, leading to myopia.
"We have invented glasses that are designed to make images on the retina more like images would normally fall when people are not reading or having things close to their eyes," Neitz said.
The glasses have a treatment on the edge that make things on the periphery blurry so that not everything is in focus, as it is naturally when you're outside, for example. That retrains the eye, and slows lengthening of the eye.
"It thinks, 'Oh, everything's cool because I'm focused close, but things in the periphery are blurry. I must not need to grow anymore,'" Neitz explained.
Kwan's had the glasses for a month and said she can already tell a difference.
"The glasses that I was accustomed to only a few months ago were now too strong for me," Kwan said.
Kids who wore the glasses in the last trial showed a 70 percent slower progression, versus those children in the control group. The next trial, which is expected to take place in the next few months, will be a bigger study. It will include children between 6 and 14 years old.