Doctors issue unusual warning for those using smartphones in the dark

Smartphones are powerhouses of information and communication technology. For most of us that means they are a permanent resource, switched on to find out anything from what our friends are up to, or even to pay our bills.But the desire to keep using our phones at night before going to sleep has now been identified as causing temporary vision loss.In a letter published Wednesday in the New England Journal of Medicine, doctors have detailed the separate cases of two women, aged 22 and 40, who experienced “transient smartphone blindness” for months.

Dr. Gordon Plant, consultant neurologist, National Hospital of Neurology, Moorfields Eye Hospital explains “It will take several minutes before the right eye can see as well as the left eye, the opposite is true of course if they’re lying on their right side. So what worries them is that they think the problem is that they can’t see with the eye that’s been exposed to the light and if they’d been viewing the phone with both eyes, both eyes would be the same and they wouldn’t think anything of it.Transient monocular visual loss, so the temporary loss of vision in one eye, is a very, very important symptom, because it can be the warning of a stroke, and it’s one of the commonest reasons that a patients coming through Moorfields (eye hospital) casualty are referred to a stroke unit because they’ve had transient loss of vision in one eye and although, of course it’s much more common in older people, even young people can have strokes and can have a risk of stroke.” says Dr. Plant.

In Thursday’s New England Journal of Medicine, doctors detailed the cases of the two women, ages 22 and 40, who experienced “transient smartphone blindness” for months.The women complained of recurring episodes of temporary vision loss for up to 15 minutes. They were subjected to variety of medical exams, MRI scans and heart tests. Yet doctors couldn’t find anything wrong with them to explain the problem.

But minutes after walking into an eye specialist’s office, the mystery was solved.”I simply asked them, ‘What exactly were you doing when this happened?'” recalled Dr. Gordon Plant of Moorfield’s Eye Hospital in London.He explained that both women typically looked at their smartphones with only one eye while resting on their side in bed in the dark – their other eye was covered by the pillow.

“So you have one eye adapted to the light because it’s looking at the phone and the other eye is adapted to the dark,” he said.When they put their phone down, they couldn’t see with the phone eye. That’s because “it’s taking many minutes to catch up to the other eye that’s adapted to the dark,” Plant said.He said the temporary blindness was ultimately harmless, and easily avoidable, if people stuck to looking at their smartphones with both eyes.

One of the women was relieved the short-term blindness didn’t signal a more serious problem like an imminent stroke. He said the second woman was more skeptical and kept a rigorous months long diary tracking her fleeting vision loss before she finally believed him. But she couldn’t stop checking her phone for messages from bed, he said.

Dr. Rahul Khurana, a spokesman for the American Academy of Ophthalmology, called it a fascinating hypothesis but said two cases weren’t enough to prove that one-eyed smartphone use in the dark caused the problem. He also doubted whether many smartphone users would experience the phenomenon.

Khurana, who acknowledged that he’s an avid cellphone user, said that he and his wife tried to recreate the scenario on a recent evening, but had difficulty checking their phones with only one eye. “It was very odd,” he said.