Marketers Distort Blue Light Evidence
Blue light will get you if you don't watch out. That's the message from the advertisers of blue-blocking glasses, computer monitors, and apps for cell phones and tablets. Their websites warn of eye strain, retina damage, and insomnia from the widespread use of light-emitting diodes (LEDs) in these devices and in light bulbs.
"Overexposure to blue light could cause all kinds of problems, including dry eyes to digital eye strain, sleep cycle disruption, and even macular degeneration," Lens Crafters warns. "Blue light gives damage to the inner part of your eye," claims the maker of the AceColor app for iPhones. The Vision Council, a consortium of eyewear manufacturers, lists "blue light filter" as a feature of computer glasses that can "prevent the headaches and light sensitivity that people who spend long hours staring at a monitor often experience."
So one recommendation from Frida H. Rångtell, a neuroscientist at Uppsala University in Sweden, might come as a surprise. "Light as bright as possible and quite a bit of blue light in offices will make you more alert and perform better," she says.
Concerns about blue light are not without justification, Rångtell and other blue light researchers say. Multiple studies have shown that too much blue light too late at night can indeed disrupt sleep. And some preliminary research has associated blue light with macular degeneration. But like the scares about dietary fat or household bacteria, these findings have prompted marketing claims that distort the evidence and ignore important nuances—including potential blue light benefits.
The controversy stems largely from the rapid adoption of LEDs, semiconductors that were first engineered to emit blue light in the late 1980s. Inventors combined a short-wavelength blue LED chip with a yellow phosphor, which partially absorbs the monochromatic blue light and re-emits it as white light with a mixed wavelength.
Compared with the incandescent light bulbs that were the standard household light source until recently, LEDs are smaller, more durable, and more efficient. That has made them the most widely used illumination in screens and monitors of all sorts.[3] In one US survey, 90% of adults who responded reported using some type of light-emitting electronic device within the hour before bedtime.
And, increasingly, LEDs are finding their way into room lighting fixtures. Impressed by the energy savings of LEDs, many countries are starting to ban incandescent bulbs. In the United States, LED home lighting mushroomed from fewer than 400,000 installations in 2009 to 202 million in 2016, one of the fastest adoptions of any technology.