2021 study connects reduced outdoor time and increased screen time with childhood myopia

Large study links virtual learning to myopia

More digital screen use and less time spent outdoors may be behind a recent rise in childhood myopia. The study, which analyzed data from 2015 through 2020, found a sharp rise in cases of myopia in 2020. The findings suggest that lifestyle changes during the coronavirus pandemic had a large impact.

Fortunately, parents can encourage some simple habit changes to help reduce their child’s risk for myopia. 

First published in JAMA Ophthalmology, the study included data on more than 100,000 children aged 6 to 13 from Feicheng, China. Researchers from China and the U.S. used school vision screenings to learn how home confinement may affect children’s eyesight.

Study shows concerning rise in childhood myopia

The study found that cases of myopia (nearsightedness) in children aged 6 to 8 rose more in 2020 than in the previous five years.

The prevalence of myopia was about three times higher in 2020 than in other years for 6-year-olds. It was two times higher for 7-year-olds, and it was 1.4 times higher for 8-year-olds. Large increases in myopia weren’t seen in children aged 9 to 13 years.

Myopia makes it more difficult to see at a distance. The most common cause of childhood myopia is extra growth in the eye's axial length. In other words, the eyeball grows a little too long. Myopia can also develop if the cornea is too curved or if the distance between the cornea and lens is shorter (a shallow anterior chamber).

Children from age 6 to 8 “may be experiencing an important period for myopia development,” the study says. “Within this age window, the plasticity of myopia is high and myopia control may be easier. Beyond this age window, the plasticity of myopia is low and myopia is harder to control during environmental changes.”

The culprits: Less time outdoors and more time using digital screens 

The study’s authors say that lifestyle factors introduced during the pandemic may be the cause of the increases in myopia. They say the rise in myopia may stem from significantly less time spent outside plus the increased use of digital screens. Both of these factors became much more common with the move to virtual learning.

LEARN MORE about environmental factors related to childhood myopia

To help curb the pandemic in China, the government shut down schools across the country from January to May 2020. During that time, more than 220 million school children were confined to their homes while engaging in virtual learning. In 2020, the researchers tested children’s vision after the lockdown ended.

The study examined the vision of nearly 124,000 children aged 6 to 13 during the pre-pandemic years of 2015 through 2019 and the pandemic year of 2020. It found that the prevalence of myopia in 2020 was greater than the highest prevalence of myopia from 2015 through 2019 for children age 6 to 8: 

• Age 6: 21.5% vs. 5.7%

• Age 7: 26.2% vs. 16.2%

• Age 8: 37.2% vs. 27.7%

The early childhood years are very important in vision development, especially when it comes to myopia. The researchers believe the vision of the 6- to 8-year-olds in the study may have been more vulnerable to the impact of these lifestyle changes.

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A large-scale U.S. study published in 2018 found 6.1% of children 5 to 7 and 18.3% of children 8 to 10 had myopia. Overall, myopia affects nearly 30% of the U.S. population.

The World Health Organization estimates that myopia could affect half of the world’s population by 2050, up from one-third in 2020.

Children with one or both parents who have myopia are at a higher risk for myopia than children with no myopic parent. But genetics can't fully account for the recent global increase in nearsightedness.

Growing evidence from other studies around the world support this study's findings. Less outdoor time, prolonged near work and too much screen time are likely factors in myopia development.

How parents can lower myopia risk for children

Some schools have gone back to a classroom or hybrid education style. But many parents are choosing to stick with virtual learning for their kids. Either way, there are important things parents can do to help lower the risk of myopia for their children:

• Ensure that kids spend plenty of time outdoors in bright daylight. Sitting near windows doesn't count. Experts recommend that children have at least 90 minutes of outdoor time each day.

• Limit recreational use of digital devices. This is important for all children, but especially for those spending several hours per day on digital devices for school.

• Encourage children to follow the 20-20-20 rule to avoid eye strain while doing close-up work (such as homework on their computers). Every 20 minutes, they should look at something 20 feet away for 20 seconds. Clinical studies have not yet proven a link between eye strain and myopia, but experts around the world recommend this rule.

Keep up with routine eye exams for your children

Another important part of ensuring your child’s best vision is to schedule regular eye exams. Pediatric optometrists and ophthalmologists specialize in the key, early years of vision development.

A child’s first eye exam should be at 6 months of age, with follow-up exams at age 3 and before first grade (age 5 or 6).

All school-age children should have an eye exam at least once per year if vision correction isn’t needed. Children who wear eyeglasses or contact lenses may need to have eye exams more often.

Children with myopia need to be monitored closely for myopia progression. If their eye doctor finds that the myopia is getting worse, they may recommend special myopia control strategies.

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Page published on Monday, March 1, 2021

Page updated on Saturday, April 30, 2022

Medically reviewed on Monday, April 4, 2022