Your parents were right: Staring at a screen all day will ruin your eyes. The only thing they got wrong was the kind of screen. Light emitted by LED-illuminated screens, the kinds you find on smartphones, tablets, and computers, kill the cells in your retinas as you use them. New research found that, in rats, three-months' worth of screen use led to a 23% increase in retina cell death.
The study arrayed regular consumer tablets around rat cages. The tablets where switched on for 16 continuous hours per day for three months, and then the retinal damage in the rats was compared to that of a control group that didn't have to stare at the screens all day long. Finally, a third group was subjected to the same conditions, only with a filter over the screens to cut out certain wavelengths of light.