Looking at your phone in the dark may cause temporary blindness in one eye! The New England Journal of Medicine has identified cases of “transient smartphone blindness.” It’s ultimately harmless and your vision comes back… but when I tell you what causes it – you’ll say, “Oh yeah! That makes sense!”

In case studies, the blindness was brought on by people using their smartphones while lying on their sides in the dark – in a way that only one eye was looking at the bright screen while the other was blocked by a pillow. That causes one eye to adjust to the darkness, while the other adapts to the brightness. Then, when the smartphone is turned off, the eye that was looking at the phone is temporarily blinded – because it’s not adjusted to the dark. And that can linger for 15 to 20 minutes. It’s harmless – and your blinded eye will eventually adjust itself. It’s like being temporarily blinded by a camera flash.

But to avoid transient smartphone blindness, stop looking at your phone with one eye in the dark.