When you look at a screen for hours on end, a variety of physiological shifts follow. As your eyes process the blue light emanating from the screen, they have to refocus it in order for it to land properly on the retina, VSP network optometrist Jennifer Tsai, OD, previously told Well+Good: “After an extended period of time, your eye muscles feel fatigued from being overworked.”
Not to mention, the natural tendency to reduce your blink rate by up to 66 percent while staring at a screen compounds that effect, triggering the dry eyes and blurry vision most often cited as symptoms of digital eye strain. But while those eye changes alone may be evidence that it’s time to turn away from a screen and focus your gaze at something at least 20 feet away—which you should aim to do for 20 seconds every 20 minutes, says optometrist Jonah Berman, OD, FAAO, citing the 20-20-20 rule—there are a few less-obvious symptoms of digital eye strain to consider, too.
“Holding screens close to the face not only taxes the visual system, but also adversely affects the musculoskeletal system by forcing us to constantly bend forward,” says Dr. Berman, on the woes of staring downward at a cellphone. And a computer screen can cause similar body strain when its height falls outside of eye level, requiring you to either hunch over or tilt your neck upward to view it, says chiropractor Kevin Lees, DC, manager of auditing and quality at The Joint Chiropractic.
Below, the experts walk through the most common symptoms of digital eye strain that can come from staring at a screen for hours, both eye-related and otherwise.
5 ways your body will tell you to look—or move—away from a screen:
1. You’re having a frequent urge to re-adjust.
This can come in the form of feeling like you need to blink a ton—to re-focus, eliminate double vision, or re-wet dry eyes—or simply like you need to keep re-crossing your legs or shifting your position.
“You may notice having to scoot up or down in your chair, or maybe lean to one side,” says Dr. Lees, which can indicate that you’ve been in one specific position for too long. “Any impulse to stop what you’re doing and either move your body or adjust your screen is a clear sign that something isn’t right,” says Dr. Berman.
2. You develop a headache.
A headache that forms behind the eyes, or any type of pain or discomfort in that ocular region, directly relates to the vision stress that prolonged screen time can cause, says Dr. Berman.
It’s also very possible that staring at a screen may trigger other types of headaches, including migraine, as well. In fact, a 2015 study of screen-time exposure and headaches in 4,927 young people (with an average age of 21) found that those in the group with the highest regular screen time had a significantly higher risk of developing migraine, too.
3. You feel neck or back soreness.
As you sink into your chair or hunch over your laptop or phone, the shift in alignment can also cause neck or back pain.
“The spine is compressed 30 percent more while sitting than when standing, and over time, this can lead to chronic shortening of muscles in your chest and your hips, and skeletal changes like osteoarthritis,” says Dr. Lees. To wit, extended sedentary periods are connected with a risk of chronic lower back pain, a herniated disc, sciatica, and degenerative disc disease, he adds. So, stretching and changing your position (by, yes, taking a break from the screens) can help.
Looking for stretches for low-back pain? Try the 13-minute guided session in the video below.
4. Your feet are swelling.
After a while, remaining crouched over a screen can limit the circulation in your legs, says Dr. Lees, causing your feet or ankles to swell or tighten. Keeping your legs crossed for that same period of time can temporarily compress nerves, too, leading to numbness or tingling in the feet. In both cases, standing up if you are able to do so, stepping away from your screen, and walking around for a few seconds can mitigate these symptoms. Elevating the feet, lying down completely, or otherwise changing your position can also help.
5. You’re having difficulty focusing or experiencing brain fog.
Stress, anxiety, fatigue, and even lack of novelty are common causes of that out-of-it feeling neurologists call brain fog, but perhaps more sneakily, so is remaining seated in front of your computer for hours on end. And it’s not just from your eyes “glazing over,” either. When you get sucked into a task and lose sight of your posture, your breathing can also be affected. “As you stoop forward, you have less room for lung and diaphragm expansion,” says Dr. Lees, which could result in fewer deep breaths overall. The decrease in oxygen to the brain can, in turn, result in foggy or unclear thinking, says Dr. Lees.
If any of the above symptoms creep up for you—and especially if you’re experiencing multiple—you can take that as a likely sign from your body that it’s time to change your position and redirect your gaze toward something that is most definitely not a screen. To maximize the benefits of that screen break, take it outside, too, if you can: Combining some light physical activity with fresh air can help reset both mind and body.
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