Looking at a smartphone temporarily blinded 2 people -- here's how it happened

Again and again, doctors tell us to unplug when we go to sleep or wake up.

Smartphone use at bedtime ruins your sleep and can give you a kind of technological “hangover.” But that’s not the worst of it: Two women in the UK each went temporarily blind in one eye, and doctors think it’s because they used their phones in bed.

As the Associated Press reported, the episodes of blindness set in, went away, and repeatedly came back over the course of more than a year.

At first, their doctors were stumped enough to stick them in an MRI machine. But a visit to an actual eye doctor cleared things up pretty quickly.

“I simply asked them, ‘What exactly were you doing when this happened?'” opthamologist Gordon Plant told the Associated Press.

Both women, ages 22 and 40, were looking at their smart-phone screens while lying on their side in bed. Each had a pillow covering one eye, and the differences in light intensity apparently caused short-term blindness. Plant and his colleagues explained the process in a letter to the New England Journal of Medicine, published Thursday.

The eye looking at the phone, they explain, adjusts itself to bright, blue-tinted light, while the eye covered by the pillow adapts to the dark.

When both eyes are exposed to equal amounts of light, the eye looking at the screen takes time to catch up. The transition is so intense that the eye seems to go blind for several minutes after putting the phone down.

The blindness doesn’t seem to be too harmful in the long term.

The Associated Press also spoke to Dr. Rahul Khurana, spokesperson for the American Academy of Opthamology, about these cases. He pointed out that two cases doesn’t make an epidemic of smartphone-induced blindness, or even prove that the phones are to blame.

Khurana and his wife even tried to mimic the women by looking at his phone with just one eye, but they didn’t succeed at blinding themselves.

“It was very odd,” he told the Associated Press. Which makes sense: When was the last time you looked at your phone with just one eye?

At least the fix is pretty simple: Turn off your darn phone — or at least look at it with both eyes.

NOW WATCH: A neurologist reveals what talking on the phone does to your brain

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