Staring at your smartphone, tablet, or computer screen for hours on end may not only be fueling your online addiction—it could be wreaking havoc on your eyesight. So says a new study out of the University of Toledo, published in the Scientific Reports journal, and it's all because of the symbiotic relationship between a light-sensitive protein in our retinas and the blue light emitted from our digital devices. What happens when that blue light hits our eyes, per the chemists involved in the research: It triggers the protein, called retinal, to produce toxic molecules that kill off the eye's non-regenerative photoreceptor cells. And once those cells are dead, "they're dead for good," study co-author Kasun Ratnayake says, per CTV News. The retinal and blue light definitely need each other to cause their damage, too: Either one on its own wasn't found to kill cells.
Over time, this process leads to age-related macular degeneration, which is the top cause of vision loss and can eventually lead to blindness. There is a Vitaman E molecule called alpha tocopherol that exists in our eyes and is able to fend off such cell deaths, but it apparently doesn't wield the same fighting powers as we age or if our immune systems are compromised. As researchers explore how to combat the problem—eyedrops that slow down macular degeneration is one such therapy on the table—study co-author Ajith Karunarathne suggests that people not check their devices when they're in the dark and to wear special glasses that can keep blue light from slamming into the retina. (Thinking about Lasik to help your own vision? There have been some concerns.)