Medically reviewed by Brandy Hall, MSN, RN, on 03/29/2023
In today's tech-driven world, with everything from TikTok to Twitter lighting up our screens with new exciting information, it can be a challenge to close our eyes and actually get to sleep.
You know how it goes. You curl up in bed with your iPad, vowing to read just one chapter of “Where the Crawdads Sing.” The next thing you know, you’re Googling an ex to see who they’re dating now, reading the latest news headlines, watching recipe videos, and searching for a great take-out Thai restaurant in your neighborhood. By the time you finally power down your iPad, your eyes and brain are too stimulated for sleep.
But why is screen time at night such a bedtime blocker? The answer lies in the literal light. Most electronic device screens are made with light-emitting diode (LED) technology, a source of blue light. While blue light is all around us — the largest source is the sun—it becomes a problem when we get too much of it before bedtime.
Enter blue-light-blocking-glasses. Also called blue light-filtering glasses, these specs have specially crafted lenses designed to reduce blue light while allowing the rest of the light spectrum to get through.
We know what you’re probably thinking: “Could wearing blue-light-blocking glasses let me have my iPad and get my shut-eye too?” The short answer: maybe. The long answer? It's not just the glasses that have anti-blue light magic.
How Blue Light Affects Our Sleep
Our sleep-wake cycle is a circadian rhythm, one of the many physical, mental, and behavioral changes that happen in our bodies during a roughly 24-hour cycle. And it's highly sensitive to the presence and absence of light. Here's how it works:
When certain cells in our eyes detect darkness, they send a message to the suprachiasmatic nucleus, or SCN, a structure located in the hypothalamus portion of our brain that's made up of about 20,000 nerve cells. The SCN then tells the pineal gland to produce the hormone melatonin, which makes us sleepy.
In the morning, when our eyes detect light, the SCNS tells the pineal gland to slow the production of melatonin so we can wake up more easily.
Sunlight is in fact one of the biggest sources of blue light, which, going back to the sleep-wake cycle explains why the majority of us feel more awake during the day. As the sun goes down, our brain gets the signal it's melatonin time. But if we're in the habit of scrolling on our phones before bedtime, the blue light from our screens can signal to the brain it's not sleepy time yet, blocking melatonin production. Over time this can become a problem.
Recent studies that covered small sample sizes (20 or fewer people) also suggests a correlation between one to two hours of night time blue light exposure and loss of sleep quality:
- One small study found that compared to reading a print book, using an e-reader one hour before bedtime prolongs the time it takes to fall asleep, cuts the amount of REM sleep, and diminishes alertness the following morning.
- Another study found that two hours of blue light exposure at night shortens sleep time, disturbs sleep, and leads to more grogginess the next day.
- Research has also found that one hour of blue light exposure stimulates the production of cortisol, a stress hormone that increases alertness and shuts off sleep.
Over time a chronic lack of quality sleep could build up to other symptoms like fatigue or stress.
What the Research Says About Blue-Light Blocking Glasses
Blue light gets a bad reputation for its connection to sleep loss, but researchers aren't completely sold on blue light blocking glasses as a solution. That's because there are no large, long-term studies looking at blue-light-blocking glasses, says Dr. Bhavna Sharma, who is an expert in sleep medicine and the Associate Program Director of Pulmonary and Critical Care at Einstein Medical Center Philadelphia.
Still, says Dr. Sharma, “Given what we know about blue light, it might be worth a try to see whether or not [wearing blue light blocking glasses] helps.”
This is what a few small randomized, controlled trials have found:
- A study on 20 adults found that wearing blue-blocking glasses three hours before bed significantly improved sleep quality and mood compared to a control group.
- A trial on 14 people with insomnia who wore blue-light-blocking glasses for two hours before bed found that compared to clear placebo lenses, the blue-light-blocking glasses improved sleep time, sleep quality, and soundness of sleep.
- A trial with 20 healthy adults who wore blue-light-blocking-glasses for a week from 6 p.m. until bedtime concluded that these glasses did not improve sleep time or quality after a week of testing.
We didn't list every study, however, due to more recent research. A 2017 meta-analysis reviewing studies on blue-light-blocking-glasses reported that they could not conclude wearing them improves sleep quality, eye fatigue, or eye health. A 2020 systematic review and meta-analysis of studies of blue-light-blocking-glasses concluded that research is mixed, but would most likely to help people with insomnia, bipolar disorder, attention-deficit hyperactive disorder, or a delayed body clock.
Which Blue-Light-Blocking Glasses to Try
If you're ready to try a pair of blue-light-blocking glasses, SleepScore recommends lenses by Swanwick, finding that the brand's orange lenses block more blue light than other lenses, with styles that include classic aviators and a fit-over pair designed to be worn with reading glasses. In SleepScore studies, people who wore the orange lenses in the evening fell asleep faster and enjoyed increased deep sleep, making them a SleepScore Validated Product.
If wearing a pair of glasses doesn't appeal, you can also try blue-light-blocking screen protectors, which you add directly to the screens of your devices, including your iPhone, iPad, or MacBook. The screens both reduce eye strain and help to protect your screens from scratches and cracks.
Other Ways to Reduce Eye Strain and Improve Sleep Quality
Dr. Sharma cautions that these specs aren’t medical devices. They haven't been approved by the FDA or any other health oversight group to ensure they do what they say they do. If you do decide to try blue light blocking glasses, you may want to double-check manufacturer claims as not all glasses provide the level of filtering that they claim.
So if you want to set yourself up for a successful night of sleep, the best thing you can do is be more mindful of when you use electronics. “It’s best to avoid blue light-emitting devices at least an hour or two before bedtime,” says Dr. Sharma. This "Tech Tuckaway" DIY project can help.
You can also try:
- Using your smartphone’s “Night Shift” or “night mode” feature and/or decrease the brightness of any screen you’re using.
- Getting plenty of activity and some sunlight during the day to help you stay alert and regulate your circadian rhythm with natural light.
- Dimming or turn off all the lights in your house a few hours before bed to get your body geared for a good night’s sleep.
- Creating a bedtime ritual that includes an old-fashioned printed book under soft lamplight. If you must use an e-reader, choose one with e-ink, which uses less blue light.
- Following The American Optometric Association's 20-20-20 rule — i.e. taking a 20-second break every 20 minutes to look 20 feet ahead of you — can also help your eyes rest.
- Blinking! We tend to rest our eyes less when staring at a screen, so blink often and consider using eye drops to keep the surface of your eyes moist.
