'Smartphone Blindness,' And Other Health Hazards Of Our Favorite Gadgets

Adding to the list of bizarre ways in which smartphones have detracted from our health and well being, doctors have coined a new one, “transient smartphone blindness.” Writing in The New England Journal of Medicine, a team in Britain outline the case studies of two women who went to a clinic complaining of temporary blindness in one eye, early in the morning and late at night, respectively. The doctors figured out that what was going on wasn’t cause for concern, but just a temporary condition caused by looking at a smartphone in the dark with just one eye. This is just the latest health-related issue that smartphones have presented as they've taken over the world in recent years; and they've certainly been known to affect more than just our eyes.

A sign advising pedestrians of the dangers of using smartphones while walking is displayed at an intersection in central Seoul. ED JONES/AFP/Getty Images

Here’s briefly what’s happening in the eyes when you use your smartphone lying in bed on your side (and that’s the key issue–when you lie on your side, one is covered by the pillow, while the other is on your phone). “We hypothesized that the symptoms were due to differential bleaching of photopigment," the authors write, "with the viewing eye becoming light-adapted while the eye blocked by the pillow was becoming dark-adapted. Subsequently, with both eyes uncovered in the dark, the light-adapted eye was perceived to be ‘blind.’ The discrepancy lasted several minutes, reflecting the time course of scotopic recovery after a bleach."

In other words, when you look at your smartphone screen with just one eye, you’re “bleaching” the light-sensitive pigments in that eye, which makes them temporarily less sensitive to regular light than the other eye. It’s the same effect as coming indoors after being in the bright sun–you feel a little blind for a few minutes, until your eyes adjust. So the same thing happens when you expose just one eye to the light; it feels “blind.” Luckily, it's temporary, and probably more disconcerting than dangerous.

Sleep problems

The one-eyed “blindness” phenomenon is just one peril of lying in bed with a smartphone. There are other, more affecting ones. Smartphones and tablets alike put off blue light, which is known to throw off our sleep-wake cycle. This happens in part because blue light reduces the amount of melatonin secreted in our brains, which we need to drift off. Studies have shown that not only is this hormone suppressed, but people who use gadgets in bed have delayed REM sleep and feel less alert the next morning. Beyond messing with sleep hormones, smartphone use in bed may just keep us up and wired longer than we’d normally be. Turning off gadgets at least an hour before bed, to let your nervous system calibrate, is what sleep experts generally recommend.

Physical ailments

Physical problems like “text neck” and “cell phone elbow” have also been described by the medical community in the last few years. Chiropractor Dean Fishman devised the term “text neck” after he saw young person after young person for neck problems, which he realized were due to the angle at which one has to bend one’s neck to look at a cell phone. Cell phone elbow happens when one talks on the phone a lot–holding the phone up to the ear, the ulnar nerve gets compressed over time, which can lead to problems with motility and sensation.


And there are certain situations in which using one’s cell phone can lead to physical danger or even death, if you’re not looking where you’re going. Texting while driving is the most obviously life-threatening, but another is texting while walking. This practice is less safe than talking on the phone while walking, since you can’t see where you’re going when you’re texting, and people have been known to absentmindedly walk into traffic. Researchers have suggested that texting while walking is responsible for not only slowing us down while we walk, but also making us veer off course. And according to research from the Pew Charitable Trusts, distracted walking injuries are rising steadily each year. Several deaths have even been attributed to gadget use while walking.


Perhaps the most famous danger of smartphones is their addiction potential. According to a recent poll, 50% of kids and 27% of parents feel addicted to their phones. There’s no formal definition for phone addiction, or uniform belief among the psych community that it’s a real phenomenon. But some consensus seems to be growing in that direction. Internet use disorder has been recommended for further study by the American Psychiatric Association, and smartphone addiction wouldn’t seem to be too far off. Since behaviors can just be addictive as substances, and many of us have felt the pull to check our phones much more often than is necessary, it’s not hard to imagine that we can get hooked on them enough that it becomes a problem.

Consciously trying to cut down on your cell phone use is probably not a bad idea, for health both mental and physical. Unless you need it for safety, try leaving it at home when you’re out, or in another room when you’re at home, or in your bag while you’re at work. Definitely don’t sleep with it, or check it in bed. Smartphones are fun, but when they start detracting from our lives and our interactions with actual human beings, it's probably time to dial it back.

If I’ve missed any cell phone dangers, please comment below.

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