This Smartphone Habit Can Cause Temporary Blindness

Do you curl up in bed at night with your smartphone? It’s a habit that could leave you temporarily blind in one eye. Sure, it’s temporary, but if you don’t know what’s happening, it’s also scary. And it can end up costing you a bundle in time and money at the doctor’s office.

An article in the New England Journal of Medicine (NEJM) explores two cases of “transient smartphone blindness,” a form of temporary blindness that happens after using your smartphone in the dark while lying down.

In both cases, the blindness occurred in the eye opposite of the side on which the patient was lying. The authors hypothesized that “symptoms were due to differential bleaching of photopigment, 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 authors believe transient smartphone blindness is likely to become more frequent as more people use them while lying down, stressing that good communication between doctors and patients can help avoid unnecessary anxiety and testing.

“Seems like the smartphone was not the cause, but rather the bleaching of photorecptors while using the phone with one eye for extended periods of time in the dark,” Cary M. Silverman, M.D., founder of EyeCare 20/20, told Care2.

“I wonder if one could mimic this by walking outside for a while on a bright, sunny day with one eye patched, then walk into a dark movie theatre and remove the patch? If the hypothesis is correct as presented by the authors, the eye that was not patched would appear to be blind in the dark for a few minutes.”

The take home message, according to Dr. Silverman, is “Use both eyes when using your smartphone in the dark!”

Silverman said there’s no evidence smartphones and other screens lead to permanent ocular or visual damage, but they can cause:

  • eye irritation
  • difficulty focusing
  • blurriness
  • neck aches
  • backaches

That’s especially true if you use multiple devices for a good portion of the day. Silverman offers the following tips to limit eye strain.

How to use your smartphone without harming your eyes

  • Pay attention to position and posture: Position of reflecting surfaces, seat height, and the angle at which the smartphone or other screens are viewed are all important.
  • Check your lighting: The intensity, focus, and clarity of letters are all major sources of eyestrain. The brightness and contrast of the display can be controlled to provide the most comfortable levels. For computer monitors, an ultraviolet and infrared filter screen placed over the monitor may also alleviate eyestrain.
  • Blink and lubricate: Periodic rest breaks are essential for comfort and relief of fatigue. It is also common for people to forget to blink while staring at a smartphone or monitor. It is important to remember to blink, or use a lubricating drop such as artificial tear substitutes while working for long periods.
  • Wear your glasses: It’s important to wear your proper prescription glasses. Uncorrected refractive errors may cause eye fatigue. People who need reading glasses may benefit from special bifocals designed for use at the computer.

Geoffrey Goodfellow, O.D., F.A.A.O., associate professor at the Illinois College of Optometry, provided these additional tips from the American Optometric Association (AOA).

  • Adjust your settings: Adjust your smartphone settings, e.g., Apple’s “Night Shift” feature, to subtly shift the color temperature of your device’s display to help filter out some high-energy, short-wavelength blue light. You can also wear special eyewear designed to block high-energy blue light.
  • Follow the 20-20-20 rule: To ward off digital eyestrain, take a 20-second break to view something 20 feet away every 20 minutes. And maintain a comfortable working distance from your digital device; use the zoom feature to see small print and details, rather than bringing the device closer to your eyes.
  • Say goodnight: Using digital devices that emit blue light before bed prolongs the time it takes to fall asleep, so say goodnight to technology at least an hour before bed.

“If you’re experiencing eye strain among other problems such as sleep disorders and, for certain patients, age-related vision problems, caused by digital screens, visit a doctor of optometry for a comprehensive eye exam and proper treatment,” advises Dr. Goodfellow. “To find a doctor of optometry near you, visit the AOA’s doctor finder at”

For more about eye health, read these stories next:
Is Eye Sunburn a Real Thing?
Spider Web Vision: Should You Be Worried?
How To Help Your Eyes Recover From Staring At Screens

Image Credit: Thinkstock


Siyus Copetallus
Siyus Copetallus2 years ago

Thank you for sharing.

Dana A.
Dana A2 years ago

Guilty as charged... walked into a few walls one eye blind...

Jim Ven
Jim Ven2 years ago

thanks for the article.

M. M.
M. M2 years ago


Jim Ven
Jim Ven2 years ago

thanks for the article.

Rebecca Gouge
Rebecca Gouge2 years ago


Melania Padilla
Melania P2 years ago

I don't do this but good to know! Thank you

Emma L.
Past Member 2 years ago

Thank you!

Mari 's
Mari 's2 years ago

Wow thanks! This is really good to know.

Rhonda B.
.2 years ago