More Screen Time Linked to Greater Risk of Vision Issues

Screens are a ubiquitous part of our daily lives—now, a new study is zeroing in on how they might be connected to worsening eye health.

The study, published last month in the journal JAMA Network Open, found that staring at screens may be connected to a greater risk of myopia, or nearsightedness. This refers to when objects close to your eyes look clear, but more distant objects in your field of vision look blurry.

Researchers conducted a meta-analysis of 45 studies—including over 335,000 participants with an average age of 9—and found that a mere one-hour daily increase in screen time could raise a person’s risk of developing nearsightedness by 21%.

The review also found that this risk of nearsightedness increased considerably when people used screens for one to four hours each day. Myopia risk continued to increase when people used screens for over four hours a day, though at a much more gradual rate.

According to one recent survey of 1,000 people, Americans spend upwards of five hours a day on their phones.

Experts have long pointed to the ways that constant screen use could be affecting our eye health. Digital eye strain caused by smartphone use, for example, can cause symptoms such as dry eye, itching, blurring of vision, and more.

The study authors said tying screen time to myopia risk in this way could provide “meaningful insights for future research” that could hopefully inform public health interventions down the line. This could be particularly important, as it’s estimated that half of the global population will develop myopia by 2050.

“With this information, eye care providers can better educate their patients and guardians on how the risk of myopia increases with each hour of screen time per day,” Laura Ann Goldberg, OD, assistant professor of ophthalmology at Johns Hopkins Medicine, told Health. “It provides guidelines that parents can use for their children on screen time that is backed by scientific data.”

This study found a strong correlation between screen time and nearsightedness, and there are several other studies out there that have found the same thing, explained Victoria Tseng, MD, PhD, assistant professor, the Jerome and Joan Snyder Chair in Ophthalmology and residency program director at the UCLA Stein Eye Institute.

However, she said, the mechanism behind this relationship hasn’t been fully explained. More research needs to be done.

But one theory is that screens could be causing nearsightedness because they’re positioned fairly close to our eyes.

Research has shown that, particularly in kids, more time spent doing “near work”—or activities such as reading, watching TV, or anything else that’s done relatively close to the eye—has been linked to myopia.

A 2022 study found that, during the pandemic, kids who did schoolwork online using a screen had more myopia progression than those who didn’t, for example.

This could be due to issues with a process called “accommodation—adjustment of the eye to focus up close,” Tseng explained.

“Another hypothesis is that imbalances in the demand and response for accommodation, or accommodative lag, stimulates the eye to grow, which makes it more myopic,” she added.

This might explain why many studies have shown “that it is not so much what type of screens people are looking at, but instead the viewing distance,” said Goldberg.

But the screens themselves are an issue, too.

Past research has shown that children tend to hold their devices closer to their faces than they do physical books, Goldberg said, potentially worsening this issue of near work.

Additionally, artificial light has been linked to poor sleep quality, which in itself can affect melatonin levels and one’s circadian rhythm—both “are thought to play a role in myopia progression,” she added.

In many of these conversations about screens and nearsightedness, smartphones and tablets are often discussed, but they’re not the only culprits.

“The present study did not specifically examine associations between specific types of devices and development of myopia,” said Tseng. “But the authors do reference previous studies which have suggested that computer and television use may be a bigger risk factor for myopia development compared to smartphone use.”

People with myopia can have their vision issues corrected with contact lenses or glasses from an optometrist.

However, developing myopia at all can result in “several downstream consequences” for your eye health, said Tseng.

Nearsightedness can raise the risk of retinal tears and detachments, which refer to “breaks and separation of the back layer of the eye,” Tseng explained. Glaucoma, as well as strabismus—or misalignment of eye muscles—are other potential issues, she said.

And screen use too can be harmful beyond an increased risk of nearsightedness.

Research has shown that glare sensitivity, squinting to reduce light exposure—which can, in turn, lead to eye discomfort—headaches, and fatigue can all accompany prolonged screen use, Goldberg said.

There is also a “strong association” between digital screen use and the increase of dry eye disease, she added. Longer screen duration has been linked to reduced blinking, Goldberg said, which can “allow for faster and greater evaporative loss.”

Based on this growing body of research, it’s clear that “limiting the duration of screen time may potentially be beneficial for reducing the risk of myopia,” said Tseng.

In fact, the authors of this new study said that spending less than one hour a day looking at a screen could be a “potential safety threshold” for reducing nearsightedness risk.

This is in line with various existing recommendations on screen time use for kids, experts said. The American Academy of Child and Adolescent Psychiatry suggests:

• Little to no screen time for children under 18 months, except for occasional video calls with family and friends
• Less than an hour per day for kids 18 to 24 months
• One hour of screen time per work day and three hours per weekend day for ages 2 to 5
• Limiting activities that use screens and encouraging healthy habits for children ages 6 and up

“Being cognizant of screen time for children is a major factor to consider, as this is when the eye is still growing, and there is potential for myopia to develop at a rapid rate,” said Tseng.

Of course, for adults who spend most of their days on Zoom calls and looking at screens for work, reducing screen time is easier said than done. For the large majority of people, keeping device use limited to one hour per day is unrealistic, particularly if your livelihood depends on it.

However, adults can keep certain habits in mind to make screen time a little easier on the eyes.

“Remember to blink often, keep the eyes lubricated with moisturizing drops, and follow the 20-20-20 rule of looking 20 feet away at an object for 20 seconds every 20 minutes to reduce eye strain,” Tseng suggested.