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Can Blue Light Blocking Glasses Really Help You Sleep Better?

With only 24 hours in a day, you likely spend a portion of your nights gathered ’round a gadget. Indeed, a whopping 90% of Americans have a pre-bedtime electronics habit, according to researchers at Boston’s Brigham and Women’s Hospital. But failure to power down may be keeping you up when you need serious shuteye. “Many of us use our phones and tablets to relax—reading, scrolling through social media, streaming our favorite shows,” says sleep expert Michael Breus, PhD. “It’s a catch-22 because studies show that the artificial blue light emitted by these devices can interfere with sleep.”

Fortunately, the solution may be as simple as slipping on some specs: those blue light blocking glasses you’ve probably noticed in your feeds between funny cat videos. These glasses have also been marketed as a way to stave off other issues associated with too much screen time, including vision-impairing diseases. And because they’ve become so trendy—a de rigueur accessory for the tech-savvy set—you’ll find more than a few brands, styles, and price points competing for a place at your bedside. So if you’re tempted to buy a pair, read on for answers to crucial questions about what blue light blocking glasses can and can’t do and how to wear them for maximum effectiveness.

What’s the big deal about blue light?

Blue light has gotten a bad rap lately, but rather than a pernicious product of modern technology, it’s a natural component of the sun’s spectrum, which has long-wavelength red (infrared) light on one end and short-wavelength blue (ultraviolet) light on the opposite end.

This natural light helps regulate circadian rhythms, the internal cycles that cue us in to when we should be active and when we should rest. “Circadian rhythms—which influence our immune systems, metabolism, appetite and digestion, cognitive performance, and mood—are kept in alignment by our daily exposure to light and darkness,” Breus explains.

How does blue light mess with sleep?

Human beings evolved to handle blue light just fine by day. Sleep problems can occur, however, when we perceive manmade blue light after sundown, especially in the high concentrations self-luminous displays emit, because our bodies believe it’s still daytime.

“Continually increasing exposure to artificial blue light throws off our biological clocks and inhibits the production of the hormone melatonin, stimulating alertness at night and decreasing alertness in the morning,” says Breus, citing a 2018 study published in Physiological Reports.

Related: Can Wi-Fi really disrupt your sleep?

So can blue light blocking glasses help you sleep better?

The concept of blocking blue light originated in the 1970s when scientists discovered the suprachiasmatic nucleus (SCN)—a small part of the brain that controls circadian rhythms—and developed glasses with orange lenses found to block as much as 100% of the blue spectrum. “The SCN is directly connected to the eyes and constantly monitors time of day based on the light coming in through them,” explains Ellen Vora, MD, a New York City-based psychiatrist who works with insomnia patients. “By blocking blue spectrum light when using electronics in the evening, these glasses help your brain understand that it’s nighttime, which lets the body shut down secretion of cortisol, the stress hormone, and ramp up melatonin secretion to allow you to fall and stay asleep.”

A 2017 University of Houston College of Optometry study proved as much, with subjects who wore blue light blocking glasses before bed experiencing an increase in melatonin, faster sleep onset, and greater sleep duration.

When should you use blue light blocking glasses—and which ones work best?

Ideally, you’d avoid exposure to manmade blue light for several hours before sleep, but experts believe blue light blocking glasses can be effective if worn within 90 minutes of hitting the sack. While it’s smart to sport them when exposed to all artificial blue light at night, including that from LCD TV sets and LED/fluorescent bulbs, digital devices are the worst offenders, largely because you hold their self-luminous displays so close to your eyes.

Skip the specs during the day (when your eyes are engineered for blue light), and purchase a pair with amber/orange lenses (like those from Uvex or Spectra) to block the maximum amount of blue light and also minimize brightness. “Clear lenses marketed as blue light blocking glasses don’t work,” Breus asserts.

Can an app effectively filter out blue light?

Many popular gadgets have built-in apps to shift screen color to the warmer end of the spectrum and reduce blue light emissions, and similar apps are available for purchase—but they haven’t proven to perform as well as blue light blocking glasses. A 2018 Rensselaer Polytechnic Institute Lighting Research Center study testing Apple’s Night Shift with the iPad found that the app failed to reverse melatonin suppression.

Do blue light blocking glasses have any other health benefits?

You may have heard the hype about blue light blocking glasses deferring eyestrain, dryness, and even retinal damage that can lead to vision loss. While experts concur that blue light, at high enough doses, can damage the cells of the human body, “exposure to typical levels of blue light from consumer electronics is negligible in terms of increased risk of macular degeneration or blindness,” David Ramsey, MD, PhD, director of Ophthalmic Research at the Lahey Hospital & Medical Center, a part of Beth Israel Lahey Health in New York City, writes in the Harvard Health Blog. “Furthermore, the current evidence does not support the use of blue light blocking lenses to protect the health of the retina, and advertisers have even been fined for misleading claims about these types of lenses.”

If eyestrain bothers you while staring at a screen, day or night, the American Academy of Ophthalmology recommends following the 20-20-20 rule: Every 20 minutes, turn away from your screen and focus on an object at least 20 feet away for 20 seconds. Eye doctors also suggest using artificial tears for lubrication to offset dryness, blurring, and irritation.

Put down the phone and read a good old-fashioned paperback at night instead. Here’s how reading in bed can help you sleep.