Much of modern society has probably heard of blue light glasses, or more accurately, blue light-blocking glasses. How could we not when we’re surrounded by blue-light emitting sources, from our desktops to our smartphones, for several hours a day? Because of blue light’s sleep-disrupting effects and supposed eye complications, many of us have turned to blue light-filtering eyeglasses in the hopes of better sleep and eye health.
But are blue light-blocking glasses actually effective? Or are they merely marketing gimmicks by eyewear companies? Skeptics may want to keep reading about what science has to say about blue light glasses' benefits relative to sleep and eye health to help you decide if you should get a pair or not. You’ll also learn that not all blue wavelengths are detrimental to sleep, so long as you get blue light early in the day.
The visible light spectrum that the human eye can see ranges from 380-780 nanometers (nm). Within that spectrum, blue light is on the shorter end of 400-490 nm. Shorter wavelengths have higher frequencies and thus higher energy. That’s why blue light is also known as short wavelengths or high-energy visible light (HEV).
Blue light is present all around us. Contrary to popular misconception, blue light doesn’t just come from digital devices like your laptops and iPads. Blue wavelengths can also be found in artificial lighting sources like LED bulbs and street lamps. What’s more, blue light can also be found in nature — roughly 25% of the Sun’s rays are made up of blue wavelengths.
At a glance, it seems blue light exposure is generally bad for your sleep. But the science makes clear whether it helps or hurts depends on the time of day you expose yourself to it. You want blue light when you wake up and throughout the day, and research shows we should avoid it as much as possible during the evening and at night.
Knowing when to get and avoid blue light is more important than ever. According to an Australian-based two-year longitudinal study that was just published in June 2022, screen time from digital devices surged from an already high percentage of 86% pre-pandemic to 94% during the pandemic. During the same period, a survey commissioned by the American Academy of Sleep Medicine (AASM) showed that 56% of Americans struggled with increased sleep disturbances since the start of the pandemic, a trend now coined as “COVID-somnia.” A systematic review published in 2022 then bridged the gap between increased screen time and poor sleep. It highlighted that too much blue light from electronic devices is the likely reason you have trouble falling asleep and staying asleep at night.
Be that as it may, blue light isn’t bad for sleep, so long as you avoid it in the few hours before your target bedtime. That’s because blue light (and light in general) acts as a zeitgeber. It’s a circadian cue that interacts with your internal body clock (your circadian rhythm) to influence your sleep-wake cycle.
Blue light exposure is actually a double-edged sword. When you get enough of it as soon as you wake up and limit it to the earlier part of the day, it can keep your circadian rhythm on course. But too much of it too late in the evening misleads your body clock into thinking it’s still daytime, which throws your sleep-wake cycle off balance, disrupting your sleep.
Let’s first explore how ill-timed blue light exposure disrupts your sleep.
A special group of neurons scientifically known as the intrinsically photosensitive retinal ganglion cells (ipRGCs) is located in your retina. These photoreceptors receive light, including blue wavelengths, from your surroundings, and project them to the suprachiasmatic nucleus (SCN) in your brain, otherwise known as the master circadian clock or master pacemaker. The light-sensitive photoreceptors work with your biological clock to influence your sleep-wake cycle for optimal circadian alignment.
Here’s how it works:
Unfortunately, when you’re exposed to blue light too close to bedtime, like when you’re watching hours of Netflix, melanopsin is hard at work, dampening your body’s melatonin synthesis. What’s more, research shows that the photoreceptors’ response to light exposure does not immediately stop in the absence of light. In other words, taking a break from all digital screens and artificial lighting at 10 p.m. doesn’t mean your melatonin production kicks in one minute later. It will take some time for the hormone to start being manufactured in your body again.
The result is lower melatonin levels and a later DLMO that pushes your Melatonin Window further back. Consequently, you find it harder to fall asleep and only manage to do so much later than your intended bedtime. You also experience poorer sleep in the form of reduced deep sleep and REM sleep. This makes it unlikely you’ll meet your sleep need (the genetically determined amount of sleep your body needs). Consequently, you rack up sleep debt (the amount of sleep you’ve missed in the past 14 days relative to your sleep need). Unsurprisingly, you wake up not feeling and functioning at your best the next day (and each subsequent day if you don’t make up for that lost sleep).
Did you know that exposure to blue light early in the morning, preferably when you wake up, and throughout the day can help you meet your sleep need more effectively?
As humans, our internal clocks run slightly longer than 24 hours. Bright morning light exposure pegs our internal clock time to the exact 24-hour clock time in our external surroundings. Failure to do so means our circadian rhythm starts later, which delays our bedtime that night.
Early blue light exposure also increases sleep pressure. This helps you fall asleep more easily by your target bedtime and ensures you sleep through the night. You can make it work for you, whether at home or at work. Per a study in the Journal of Clinical Sleep Medicine, workers with more daylight in their offices slept about 46 minutes longer than those in windowless workplaces.
Even if you don’t have the opportunity to get bright, natural light during office hours or throughout the day, there’s a potential workaround. The previous study highlighted that artificial blue light may compete with natural light as an entrainer for the internal body clock. More scientific evidence shows that exposing yourself to blue-enriched light in the morning is enough to stabilize the internal clock, cut down on wake-up grogginess, and improve reaction times.
Another study also sang the praises of well-timed blue light exposure during the day. Basking in blue light for as little as 30 minutes enhanced one’s alertness levels and working memory performance. Similarly, a 2021 study found that mildly sleep-deprived students exposed to blue wavelengths had better processing speed, working memory, and procedural learning.
Even shift workers, jet laggers, and people with delayed sleep phase disorder can benefit from light therapy and other lighting solutions to optimize their energy potential during wakefulness. In particular, a 2021 meta-analysis involving shift workers showed that moderate light intensity worked better for reducing sleepiness. Meanwhile, higher light intensities were more effective for shifting the sleep phase and minimizing circadian misalignment.
The bottom line is that blue light exposure in the early morning (or as soon as you wake up) is necessary for keeping your circadian rhythm on track. This, in turn, helps you fall asleep by your target bedtime and sleep through the night to meet your sleep need and keep your sleep debt low.
Blue light has a bad rep for causing digital eye strain and unwanted symptoms like dry eyes, blurred vision, and eye fatigue. It’s even touted by eyewear companies as a risk factor for eye diseases like cataracts and age-related macular degeneration. But the truth is, blue light isn’t actually bad for your eyes, at least not in the amounts from the average computer screen or smartphone.
Per an article published in the American Journal of Ophthalmology in February 2022, “the blue light hazard is misused as a marketing stratagem to alarm people into using” blue-light blocking glasses. Blue light hazard refers to “abnormally intense exposure” to harmful blue light that damages the retina, like gazing at the sun without sun-protective eyewear. The researchers highlighted that the term "blue light hazard" “has been misused commercially to suggest, falsely, that ambient environmental light exposure causes phototoxicity to the retina, leading to age-related macular degeneration (AMD).” In fact, there's an “absence of proof that environmental light exposure or cataract surgery causes AMD.” Plus, large-scale epidemiological studies proved that blue-light blocking glasses don’t downplay the odds of AMD or its progression. What’s more, the researchers cautioned that insufficient blue light (read: dim light settings) only increases the dangers of falls and other injuries.
For these reasons, the American Academy of Ophthalmology (AAO) highlighted that “it’s not necessary to spend money” on computer glasses to address digital eye strain.
As you’ll know by now, blue light isn’t to blame for digital eye strain. Instead, it’s the prolonged exposure to digital devices and lack of proper eye health practices — like regular eye breaks from your screens — that contribute to eye fatigue.
For proof, scientists conducted a randomized controlled trial to test the effectiveness of blue light-blocking glasses concerning digital eye strain, aka computer vision syndrome, that causes common complaints like dry eyes, blurry vision, and migraines. The results showed that “blue-blocking lenses did not alter signs or symptoms of eye strain with computer use relative to standard clear lenses.”
Instead of resorting to blue-light blocking glasses that don’t actually do anything for computer vision syndrome, take eye breaks every 20 minutes and stare at something that’s 20 feet away for at least 20 seconds. For dry eye issues, try eye drops. Contact lens wearers may also want to switch to reading glasses to minimize irritation.
If your symptoms persist, schedule an eye exam with an optometrist or ophthalmologist for an in-depth diagnosis.
So far, you’ve learned that blue-light filtering lenses don’t actually do anything for digital eye strain. But what about using them to improve your sleep?
The benefits of blue-light blocking glasses for healthy, naturalistic sleep and optimal energy levels are substantial and backed by science. These glasses block out all sources of blue light, from social media apps on your phone to the overhead LED lights. Without blue light entering your eyes, melanopsin isn’t activated to stop melatonin synthesis. This allows your body to produce the melatonin you need to help you fall asleep and stay asleep throughout the night.
If you need more scientific proof, a 2021 systematic review shared substantial evidence for blue-light filtering glasses helping insomniacs, jet laggers, and shift workers fall asleep more quickly. Another study found that blue-light blocking glasses toned down the activity of ipRGCs in the retina, which led to a 58% increase in nighttime melatonin levels in participants! And parents would be delighted to hear this: one study discovered that blue light lenses stopped melatonin suppression in teenagers who used light-emitting devices, like their beloved smartphones.
There’s a catch, though: you can only reap these benefits when you wear blue-light blocking glasses at the right time, i.e., at least 90 minutes before your Melatonin Window. By reducing the amount of melatonin-delaying light into your eyeballs, these glasses help preserve the timing of your Melatonin Window to give you the best chance of falling asleep and staying asleep. In other words, you're more likely to meet your sleep need and stay circadian-ally aligned.
To help you take advantage of these perks, add the “Block All Blue Light” habit to your Energy Schedule. You'll receive a personalized reminder when to wear your glasses based on your unique chronobiology. RISE users on iOS 1.202 and above can click here to set up their Block All Blue Light reminder.
While wearing blue-light blocking glasses is one of our favorite tips for getting the sleep you need (just because of how potent ill-timed light exposure is as a sleep disruptor), the reality is that even when used properly, this eyewear isn’t enough to overcome poor sleep hygiene on its own.
To maximize the sleep-promoting effectiveness of blue light lenses, you’ll want to steer clear of all sources of blue light in the four hours before your target bedtime (which should ideally be within your Melatonin Window). Use dim lighting at night as much as possible and keep your bedroom pitch-black for sleep. We also recommend using an eye mask. Compared to a dimly lit room, moderate amounts of ambient lighting in your bedroom pose a cardiovascular risk during the night and intensify insulin resistance the next day, a Northwestern Medicine study in PNAS warns.
Pair these sleep-promoting tips with blue-light exposure early in the morning and throughout the day. If you need help knowing when to bask in blue light and when to avoid it, add the “Blue light control” habit to your Energy Schedule in the RISE app.
Fun fact: Our eyes aren’t the only organs receptive to blue light; our skin also absorbs these wavelengths. While there’s no direct proof connecting blue light absorption of the skin and poor sleep, there are peripheral clocks in our skin cells that may be influenced by too-late blue light exposure impacting skin health and more.
Now that you’re convinced of blue light glasses’ benefits for sleep, you probably want to get your hands on a pair. Before you do, take note that not all blue-light blocking glasses are created equal.
Thanks to eyewear companies’ targeted ads, many people think computer glasses with blue light-filtering lenses will work for better sleep tonight. Unfortunately, that’s not the case, as these clear lenses do not filter out all blue wavelengths that disrupt sleep. Instead, your best bet is amber (orange) lenses. A 2018 study showed that insomniacs who wore amber lenses two hours before bed slept better than those who used clear lenses.
And for the proverbial cherry on top, the best blue-light blocking glasses are relatively inexpensive and widely accessible. As a 2019 study noted, blue-light-filtering efficiency "did not correlate with price." The pair we recommend is only a little over ten dollars and can fit over prescription glasses for spectacle-wearers.
Blue-light blocking glasses help you fall asleep and stay asleep when used at the right time, i.e., 90 minutes or so before your target bedtime. But that’s not to say you should avoid blue wavelengths 24/7. You still need blue light when you wake up and throughout the day to keep yourself in circadian alignment, which, in turn, has the added benefit of helping you meet your sleep need more effortlessly.
If you need help deciding when to get blue light and when to avoid it, try the RISE app. Its 20+ science-backed habits, including “Block All Blue Light” and “Blue Light Control,” provide personalized in-app reminders based on your unique chronobiology to help you fulfill your sleep need. Because when you sleep better at night, you’ll have better energy levels during the day.
Blue light glasses are actually useful for helping you fall asleep and stay asleep when worn at the right time, i.e., at least 90 minutes before your target bedtime. On the other hand, scientific evidence indicates that blue light glasses don’t actually do anything for eye health.
While science shows that blue light glasses aren’t effective in addressing digital eye strain, these eyeglasses aren’t harmful to your eyes either. Wearing blue light-filtering lenses will likely not improve or worsen your eyesight.
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