Smartphones Can ‘Blind’ You – Using Phone While Sleeping Can Cause Transient Vision Loss, Claim Researchers

Smartphones can cause transient blindness if used before sleeping, caution researchers. Relying on a couple of patients and a series of tests, researchers have cautioned against using smartphones while in bed.

Researchers have found at least two women who reported having experienced temporary blindness owing to their smartphones. Known as transient smartphone “blindness”, the condition can last anywhere between a few minutes and an hour. Though not permanent, the blindness can affect optimum functionality of the eyes and may be harmful in the long run.


Researchers are now cautioning people who sleep with their devices next to them. The use of smartphones while in bed is rising rapidly. People often take their smartphones to bed and continue using them in complete darkness, reported The Guardian. Moreover, it is often the first thing people reach out for in the morning, even before their eyes have been accustomed to the daylight outside. Such abrupt and prolonged exposure to the smartphone screen can mess with the eyes, blinding them temporarily.


Researchers relied on two patients to prove their hypothesis, reported The Register. One of them is a 22-year-old woman in England, who confessed she had the habit of gazing at her smartphone for long periods of time before falling asleep, reported National Public Radio.

“She would lie on her left side and look at the screen primarily with her right eye. Her left eye was often covered by the pillow.”

The other patient, in her 40s, had similar problems when she woke up before sunrise and checked the news on her smartphone before sitting up, reported Times of India. Both women had kept up with the routine of using their smartphones before and after their night’s sleep for over a year, when they started noticing blurry vision, shared Omar Mahroo, ophthalmologist at Moorfields Eye Hospital in London and an author reported in a paper published in The New England Journal of Medicine,

“They were looking at their smartphones and they just happened to have one eye covered because they were lying in bed. In both cases, nothing bad was going on. However, one retina was adapted to light and the other to dark. The retina is pretty amazing because it can adapt to lots of different light levels, probably better than any camera.”

What Mahroo was referring to, was the amazing ability of the human eye to constantly adjust to the varying intensities of light that keep hitting them. The readjustment is strongly noticed when one exits a dimply lit room and steps outside or goes inside after being outdoors.


To make sure the problems weren’t fleeting, researchers asked the two patients to view the smartphone with just the left eye and then just the right eye on separate occasions. As expected, the women realized that the eye going temporarily “blind” was always the one that was being used to look at the bright screen. Thereafter, the women were asked to step into a dark room, and with one eye covered, were to stare at their smartphone for about 20 minutes before turning the screen off. The results of the tests were quite consistent with the women’s previous experience, shared Mahroo,

“It did actually feel quite strange. t would be very alarming if you didn’t know what was going on.”

How can smartphones cause blindness? Researchers stress that the phones aren’t causing permanent blindness, but they are certainly impairing vision and hindering the ability of the eyes to take in all the visual information presented to the person who has been staring at their smartphone.


Researchers describe the blindness as temporary vision loss, and the incidents are steadily rising due to the spike in smartphone usage, especially at night and early morning. To ensure you are not causing any long-term damage, the simplest method would be to avoid taking your smartphone to bed, advise the researchers.

[Photo by Yiu Yu Hoi/Getty Images]