If you often spend time in front of digital screens, there's a good chance you’re not sleeping as well as you could be. You can blame it on the sleep-disrupting blue light from your gadgets. That's because blue light exposure too near to bedtime throws a wrench into your circadian rhythm (your body's internal clock), keeping you from the sleep you need.
What you lack is a pair of blue-light blocking glasses. Perhaps you're raising your eyebrows in skepticism and asking, "Do blue-light blocking glasses work?" If that's the case, this article will show you the science behind blue-light blocking glasses, and why they are possibly the most cost-effective investment for feeling and functioning at your best.
Please note: The information provided is not intended as medical advice.
So, what is blue light? The visible light spectrum ranges from 380-780 nanometers (nm). Blue light sits between 400 nm and 490 nm, which is why blue wavelengths are also called short wavelengths.
Because blue light is scientifically "shown to enhance alertness and vigilance," blue light exposure in the few hours leading up to your bedtime is generally thought to disrupt your circadian rhythm as it signals to your body it is still daytime.
In fact, research shows our eyes are much more receptive to light in the latter part of the day onward. Dim lighting as low as 25 lux (for context, sunlight has an illuminance of up to 100,000 lux) in the evening is enough to suppress half of your body’s melatonin production. (Melatonin is a sleep-promoting hormone.) Consequently, you take longer to fall asleep (increased sleep latency) and have trouble sleeping through the night (increased sleep fragmentation).
But that’s not to say, you should avoid blue light at all times. The reason being, your body needs light (including blue light) in the morning to kickstart your internal body clock for optimal circadian rhythm functioning. So, the primary issue isn’t about avoiding blue light sources 24/7. Instead, be strategic about when you should and should not bask in blue light to help you get the sleep you need while keeping your circadian rhythm running smoothly.
As much as we wish to switch to a pitch-black environment as we wind-down for bed, that isn't entirely possible or realistic. This is where blue-light blocking glasses come in handy. But, before we go into the proven efficacy of blue light blocking lenses, let's first look at how blue light exposure interferes with sleep.
You probably don’t realize how powerfully light (particularly blue light) interacts with your biological clock to impact your sleep-wake cycle. As we’ve mentioned, light exposure too close to your bedtime thwarts your efforts for meeting your sleep need.
Contrary to popular belief, your biological clock isn’t a single internal clock. It's actually a network of peripheral clocks distributed across organ systems and cells. The master circadian clock — called the suprachiasmatic nucleus (SCN) — runs these peripheral clocks on a tight ship. The SCN receives internal and external circadian cues to kick off a series of biological processes pivotal to your day-to-day functioning.
Among these circadian cues, light exposure is the most potent one for humans. Light starts and stops your circadian rhythm, which in turn, influences your wake and sleep times. In that sense, light (especially blue light) acts as a double-edged sword that can keep your body clock on track or throw it off course.
When it comes to keeping your body clock on track, it’s very important to get light first thing in the morning. This is the cue to your body to suppress melatonin now that it’s morning, but it also tells your body to start producing melatonin again 14-16 hours later.
However, as we mentioned, light can also throw your body clock off course and cause circadian misalignment. To understand how circadian misalignment holds you back from the sleep you need, let’s take a look at the interaction between nighttime blue light exposure and your body’s melatonin production.
Two to three hours before your bedtime, your body starts producing melatonin. This is called the dim light melatonin onset (DLMO) and marks the start of your daily Melatonin Window in the RISE app. Your Melatonin Window is the window of time in which your body generates peak levels of melatonin to give you the best chance of falling asleep and sleeping through the night, and you need to go to bed during this window to take advantage of it.
Unfortunately, blue light exposure foils your body's attempts to synthesize melatonin. This is due to a special group of neurons in your retina called the intrinsically photosensitive retinal ganglion cells (ipRGCs). The ipRGCs send light signals to the SCN to run interference with your sleep-wake cycle.
Although the primary function of ipRGCs is to promote circadian alignment, untimely blue light exposure can lead to the opposite. That's because ipRGCs express the photopigment melanopsin. In the presence of blue light, melanopsin suppresses your natural melatonin production. This will delay your Melatonin Window, and you naturally find it harder to drift off to sleep at your normal bedtime.
The reason being, ipRGCs' response to light exposure does not immediately turn off in the absence of light. It will take some time for your body's melatonin production to start working again after you've extinguished all light sources. Predictably, your target bedtime is pushed back further. This cuts into your sleep duration and hikes up your sleep debt (the amount of sleep you’ve missed out on over the past 14 days relative to your sleep need).
Research also indicates blue light exposure disrupts normal sleep patterns as it:
All of these blue-light-induced biological changes prevent you from getting naturalistic sleep — meaning you wake up not feeling and functioning at your best.
So, do blue-light blocking glasses work? The answer is a resounding yes. Blue-light blocking glasses primarily work to:
Here’s what happens when you put on blue-light blocking glasses:
As you can see, the simple act of wearing blue-light blocking glasses helps preserve your Melatonin Window and promote circadian alignment, both of which are essential for meeting your sleep need.
Several studies also back up the effectiveness of blue-light blocking glasses:
With a stamp of approval from the scientific community, there's no reason not to take advantage of the sleep-promoting benefits of blue-light blocking glasses. The good thing is that you don't need a prescription to buy them. Nor do you need to spend big bucks, as you'll see in a moment. But here are some important things you need to keep in mind about choosing and using your blue-light blocking glasses.
Because ipRGCs are capable of "very long-lasting light responses," exposing yourself to blue light for an hour can sustain melanopsin production longer than that. To maximize the sleep-inducing benefit of blue-light blocking glasses, we recommend wearing them at least 90 minutes before your Melatonin Window. The RISE app gives you a timely nudge when you add the "Block All Blue Light" habit to your Energy Screen.
The rationale is to give your body sufficient time to wane its melanopsin content and start up its melatonin production. By the time you're ready for bed, your body will likely be suffused with optimal melatonin levels. Predictably, you fall asleep easily and stay asleep throughout the night.
Some people assume computer glasses with blue light filters will suffice as blue-light blocking glasses. Unfortunately, these spectacle lenses are typically clear and aren't immune to all blue wavelengths. Instead, you should go for orange (amber) lenses.
In the scientific literature, a 2009 study pitted the effectiveness of wearing blue-blocking amber glasses against ultraviolet-blocking yellow ones three hours before sleep. The amber group showed significant improvements in sleep and mood compared to the yellow group. Another 2018 study also confirmed wearing amber lenses for two hours before bed improved sleep in insomniacs compared to clear lenses.
The good news is, you don't have to shell out much for a pair of blue-light blocking glasses. In fact, a 2019 study shared that blue-light-filtering efficiency "did not correlate with price." You can easily find affordable ones on Amazon, such as this pair of blue-light blocking glasses with orange lens. It can fit over prescription glasses, too.
Yes, blue-light blocking glasses are some of the most important — and easiest — things you can do to meet your sleep need. But that's not to say they are a cure-all if you have poor sleep hygiene to begin with. The truth is, relying solely on blue light lenses as a quick fix won't help you get the sleep you need. They are only truly effective when you already have the other tenets of good sleep hygiene down pat.
If you need a step-by-step guide to better your sleep hygiene, check out our Sleep Guide.
At this juncture, perhaps you're still apprehensive about using blue-light blocking glasses. After all, there are other ways to block blue light, right? For example, doesn't the night mode on your phone work just as well?
Although these blue-light blocking functionalities expose you to warmer colors on the light spectrum, they aren’t foolproof against the sleep-delaying effects of blue light. In fact, a new study featured in the Journal of Sleep Health shows the iPhone's Night Shift feature has no beneficial impact on sleep.
In the study, 167 young adults were split into three groups:
The results declared there were "no differences in sleep outcomes attributable to Night Shift." The study also noted that those who abstained from screen time slept better than those who turned on Night Shift on their phones.
Moreover, even if your eyes are protected from gadget-esque blue light, there are other indoor and outdoor sources of blue wavelengths to contend with. Even if you install dim lights and light-blocking curtains or navigate by candlelight during your wind-down (all of which we recommend!), there may be times when you're caught off guard by the sneak appearance of blue light — cue your refrigerator's light bulb when you're craving a nighttime snack.
As you can see, it's far easier to don a pair of blue-light blocking glasses. All you need to do is get used to the idea of wearing them before bed. The RISE app can help you with that. Add the "Block All Blue Light" habit to your Energy Screen, and you'll receive an in-app notification 1.5 hours before your Melatonin Window.
Excessive screen time manifests as various symptoms of digital eye strain, such as dry eyes, eye fatigue, and blurry vision. If you're using blue light glasses to tackle digital eye strain, it may be a fruitless attempt.
First up, the blue light from digital devices doesn't actually cause eye strain or eye diseases like macular degeneration. Rather, it's the long periods of time spent in front of a screen that gives rise to computer vision syndrome.
To relieve eye strain from staring at your computer screen all day, follow these eye care tips:
If your symptoms still persist, consult an ophthalmologist (an eye doctor) to rule out any underlying vision problems.
Provided that you're already practicing good sleep hygiene, blue-light blocking glasses help you meet your sleep need. Sleeping better at night gives you the best chance of having better energy during the day to do the things that matter most to you.
The trick is to wear your pair of glasses at the right time, so you're well-protected against the sleep-disrupting effects of blue light. RISE can help you build sleep-promoting habits with ease from dawn till dusk, including when to wear your blue-light blocking glasses in the evening. Get the RISE app today for better sleep and better days.
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