Recently, several friends have mentioned they seem to sleep much better when they wear blue light-blocking glasses throughout the day. Which got me wondering — can blue light blockers really make a difference in sleep quality? Here’s what science has to say.

First of all, what exactly is blue light? The world is filled with electromagnetic energy, which travels around us, and even through us, in waves. Most electromagnetic waves are invisible, but a small band of waves, known as visible light, can be detected by the human eye. Blue light is one of them. The sun emits blue light, as do fluorescent and incandescent light bulbs. Humans are exposed to more blue light than ever because of the widespread use of devices that rely on LED technology. Computer and laptop screens, flat-screen televisions, cell phones and tablets all produce high amounts of blue light. Odds are, you’re reading this article on a device that’s emitting blue light. Since blue light has been linked to problems like blurry vision, eyestrain, dry eye, macular degeneration and cataracts, more and more people have been turning to blue light-blocking glasses. And the benefits don’t stop with eye health.

Our 24-hour circadian clock regulates sleep and wake cycles, hormonal activity and other important processes within the body. Special photoreceptors in the eye detect light to control our circadian rhythms, and these cells are particularly sensitive to wavelengths on the blue-violet end of the spectrum. This is fine during the day because it helps synchronize our internal clocks. But exposure in the evening works against what nature intended. So if, for example, we’re binging on a TV series on our laptops in the hours before bed, it can interfere with our sleep — because this type of activity stimulates the melanopsin-containing cells and tricks the brain into thinking it’s daytime. And when you are deprived of darkness, it inhibits your pineal gland from secreting the hormone melatonin, which tells your body to get tired and go to sleep. And this can wreak havoc on the quality of your sleep.

So, can utilizing blue light blockers in the evening really help us get a good night’s sleep? There’s a growing body of evidence that says yes. The National Institute of Health reviewed 24 studies to determine just how effective wearing blue light-blocking glasses is when it comes to people’s ability to fall asleep more quickly, avoid insomnia and cope with jet lag and variable work schedules. The conclusion was that wearing these special glasses in the evening, when our light exposure should be at a minimum, was an effective option for people struggling with sleep issues. Studies show that when people use blue light-blocking glasses, even in a lit room or while using an electronic device, their bodies produce just as much melatonin as if it were dark. Blue light glasses have also been found to greatly improve sleep in shift workers when worn before bedtime. What’s more, in a study of older adults with cataracts, blue light-blocking lenses improved sleep and significantly reduced daytime dysfunction. In addition to glasses, experts also recommend avoiding screen use as much as possible after dusk — especially within two to three hours of bedtime.

So, if you want good, sound slumber, try blue light blockers in the evening. And maybe, just maybe, pick up a book instead of binging TV before bedtime.