From The Eye Book published by The Johns Hopkins Press
Blue light: What’s the concern about blue light? Why are people anxiously buying eyeglasses that claim to filter out blue light emitted from computers, smartphones, and tablets? Should you be concerned? Like the warning some people give to their kids that sitting too close to TV is bad for the eyes, worries about the harm of blue light emitted by digital device screens on the eyes is not supported by scientific evidence. Simply said, “there is no evidence that the kind or amount of light coming from computer screens is damaging to the eyes.”
Blue light is everywhere. Although blue light is emitted from computers, smartphones, and tablets, the largest source of blue light exposure is from sunlight. Even with the amount of blue light that we receive directly from light exposure from the sun, there has not been any evidence of damage or harm to the eye, but research is ongoing. In fact, cutting out blue light exposure during the daytime can have a negative effect on a person. Blue light has been shown to affect our circadian rhythm (our natural cycle of being awake to falling asleep) by suppressing the body’s melatonin production. Blue light wakes us up and helps keep us alert while we are awake. At night, too much blue light from a mobile phone or computer screen may make it difficult to fall asleep. Therefore, altering our blue light exposure can potentially play havoc with our day.
You may have thought that the eyestrain you feel when working on the computer is from blue light emitted from the digital screen--after all, that’s what your friend said. Well, stop scapegoating blue light. When you stare at anything for a long period of time, you can feel eyestrain, primarily because you don’t blink as often as you should, and this leads to dry eyes. So, before you run out and buy the next latest and greatest blue light filtered glasses advertised to “prevent” eyestrain, try the 20-20-20 rule. For every 20 minutes that you stare at a digital screen, look at least 20 feet away at something to relax your eyes for at least 20 seconds. Also, position your screen at least an arm’s length away, cut the glare, and use artificial teardrops when your eyes feel dry or tired. If these steps don’t do the trick, please see an eye doctor. Your problem may be due to trouble with accommodation at the distance of your screen, and a pair of prescription glasses may be just what you need.