By Liv Osby

Vision experts say that American children are becoming more nearsighted, but they’re not sure why.

Research suggests that it’s linked to spending less time outdoors than earlier generations, said Dr. Kurt Heitman, an ophthalmologist with Southern Eye Associates in Greenville. But whether it has to do with increased screen time isn’t known, he said.

 

“We’re seeing this trend where more children growing up these days are not just becoming nearsighted, but highly nearsighted,” he said. “People are calling this an epidemic.”

Dr. Alison Smith, an ophthalmologist with Clemson Eye in Greenville, says the jury is still out on the increase in nearsightedness, also called myopia. Most of the existing research has been focused on Asia, she said, noting more research needs to be done. 

 

“Maybe there is an increase in myopia,” she said. “We don’t know why.”

The trend caught the attention of ophthalmologists in the last 25 years, Heitman said.

Many people are mildly nearsighted, he said, noting that it’s the most common refractive error.

Myopia starts in childhood, he said. And the younger the child is when it’s first discovered, the more nearsighted he will be.

“If they started when they were 5 or 6,” he said, “they could be very nearsighted, changing prescriptions every year.”

Roughly 25 percent to 30 percent of children are myopic now, Heitman said. But if current trends hold true, half of all children worldwide will be myopic by 2050, he said, and about 20 percent of them will be highly myopic.

Though this is happening worldwide, it’s more common in Asia and less common in developing countries, he said.

But Smith says that children in developing countries are not screened for myopia like they are here or in Asia.

“I have spent time in rural India and those kids are not getting screened,” she said. “It’s like apples and oranges.”

The rate of myopia is much higher in Asia, according to the American Academy of Ophthalmology. But rates are higher in the U.S. than they were two generations ago, Dr. Michael X. Repka, professor of ophthalmology and chief of pediatric ophthalmology at Johns Hopkins University, said in the January 2020 issue of AAO’s Eyenet Magazine.  

There is a genetic component to myopia, said Dr. William Steigerwald, an optometrist at Southern Eye in Simpsonville.

“If both parents are nearsighted, then each child has a 50-percent chance of having it,” he said. “If one parent is nearsighted, there’s a one-in-three chance. And if (neither) is, there’s a one-in-four chance.”

But that doesn’t explain the increase by itself, the doctors say.

Researchers are investigating a theory that this is happening because children aren’t spending as much time outdoors as they used to, Heitman said.

“It’s not necessarily the time on cell phones or computers or close work. It seems to be related to the decrease in outdoor time,” he said. “Is it because when you’re outside, you’re using your eyes more for distance? Or is it something to do with exposure to sunlight? Or both?”

While research has linked time outdoors with slowing the progression of myopia, Smith said that epidemiologically, the only strong association is with exposure to light. Light does play a role in eye development, she said, and the eye needs at least two hours of natural light a day. 

Smith said the research hasn’t been able to show a strong correlation to screen time. 

But when children are inside, they’re watching TV, playing video games, reading a book, or are on their phones, Steigerwald said, so it’s difficult to exclude those things. 

Nonetheless, Smith said that most ophthalmologists link eye strain to increased screen time, if not myopia.

“The rule is that for every 20 minutes of screen time, you look away for 20 minutes,” she said. “And I am a big proponent that kids should spend less screen time and more time playing outdoors.”

Myopia can impact activities like sports and school work, Heitman and Steigerwald said, forcing children to wear glasses or contacts. 

But more importantly, high myopia increases the risk for retinal detachment, glaucoma, cataracts, and other conditions as people get older, the doctors said.

“This is not just more people wearing glasses,” Heitman said. “High myopia increases the risk of permanent damage to the eye … (and) then there’s increased risk for other pathologies. So once we catch these children, we want to keep them from becoming highly myopic.” 

Treatments to slow the progress of myopia range from atropine drops that dilate the pupil and slow the focusing mechanism of the eye to hard contact lenses that can mold the cornea, he said. Another study is underway looking at soft contact lenses, he said.

Steigerwald said he has patients who are using the drops and both types of contacts, and all three help slow progression to some degree. 

Children typically begin treatment between 8 and 12 years old, he said, adding that the type of treatment is based on the child’s lifestyle, age and ability to use contact lenses.

The usual side effects associated with atropine are stinging when applying the drops and a slight chance of light sensitivity, which is monitored, and the drops are discontinued if that happens, Steigerwald said.

The risk profile for contacts is no different than standard contact lens wearing, he said, with the disposable soft lenses having the lowest risk of eye infection and complications.

Smith says that while children should be screened and treated for myopia, she doesn’t support use of hard contacts for this purpose because of the potential for infection and other complications.

A lot of research is underway into why myopia is on the rise, Heitman said, noting the American Academy of Ophthalmology is leading the charge to find the answer.

“At the end of it, we know the numbers are going up regardless of the fact that we don’t know the cause,” Steigerwald said. “We want to try to educate parents about the risks and what if anything you can do about it.”