Admittedly, I used to think blue blocking glasses were a little gimmicky. But the more I dive into the science, the more I think they are an essential tool in the shift worker’s tool kit.
If google search trends are any indication, interest in blue-light-blocking glasses has skyrocketed since mid-2017. You can find a wide range of information and recommendations on the subject with a quick google search.
Unfortunately many of the recommendations are not particularly helpful for shift workers, frequent fliers, or anyone trying to optimize sleep. A lot of sites concentrate on “computer” glasses that help reduce eye strain from prolonged screen use. These computer glasses may work as advertised, but we shift workers require a little more specificity in our lens selection.
In this article I’d like to clear up some misconceptions about blue-light-blocking glasses, as well as blue light in general.
I’ll also provide you with the information necessary to pick the best pair(s) of blue-light-blocking glasses for your particular situation.
The benefits of blue-light-blocking glasses for shift workers
Improved Sleep
Blue light has the greatest capacity to suppress melatonin, a hormone that signals to the body that it’s time for sleep. The shift to modern energy efficient lighting from LEDs, CFLs, as well as the screens on our electronic devices, is exposing us to far greater amounts of blue light than ever before.
People who filtered out blue wavelengths for three hours before bed had a 58% increase in melatonin levels, as well as increased sleep quality and duration.1 Also, a pilot study looking at night shift workers specifically showed improved sleep quality and duration for those that wore blue-light-blocking glasses from the end of their shift until they were home in bed.2
Reduce the negative health risks linked to shift work
Night shift work is associated with multiple health risks including diabetes, obesity, heart disease, cognitive decline, mood disorders, premature aging and some types of cancer.
Although more studies are needed to identify the exact mechanism, the main culprit is thought to be nighttime light exposure and its effect on the biological clock. Wearing proper blue-light-blocking glasses at appropriate times could go a long way towards mitigating these health risks.
Helps your body adjust to schedule changes
Light is the biggest synchronizer of circadian rhythms. Without control over the lighting environment, it will be impossible to fully adapt to a night shift schedule.
We can’t prevent the sun from rising, and often have little to no influence over workplace lighting. Blue-light-blocking glasses are an easy way to regain some control and help the biological clock synchronize with the work schedule.3
Ease of implementation
There are many lifestyle choices shift workers can adopt to lower their health risks. Eating healthy, exercising, fasting, and avoiding cigarettes and alcohol to name a few. And although I highly suggest adopting better habits around these lifestyle choices, I acknowledge that it can take substantial willpower to do so.
Filtering out harmful blue light on the other hand, is the low hanging fruit to go after first. Simply purchase a pair of blue-light-blocking glasses and wear when appropriate.
When is blue light beneficial?
You don’t want to wear blue-light-blocking glasses all day. While blue light can be harmful, particularly to our melatonin cycle, it is only inappropriately timed blue light that we want to avoid. To maintain a healthy circadian system, light exposure at the right time is just as important as avoiding it at the wrong time.
Correctly timed blue-light improves mood, promotes wakefulness and can also help memory and cognitive function.4,5 Light therapy, using light boxes that emit blue-light, has been shown effective in treating seasonal affective disorder (SAD) and shift work sleep disorder (SWSD) as well.6
Blue light also has the capacity to advance, or delay circadian rhythms – which could be good or bad depending on your upcoming schedule. This point is important for shift workers and frequent fliers, and a prime reason to invest in a quality pair of blue-light-blocking glasses.
What to look for when buying blue-light-blocking glasses?
Blue-light is generally considered as the visible part of the light spectrum ranging from 380 nanometers (nm) to 500 nm. This is also the part of the spectrum most disruptive to our circadian systems.
While glasses that filter out blue-light up to 450 nm may be effective for reducing eye strain, they are not sufficient for preventing, or facilitating circadian phase shifts.
At the very least, your glasses should block everything below ~480 nm. This is the wavelength which has been shown to cause peak melatonin suppression. But, as you’ll see in the image below, wavelengths beyond 500 nm (green light) can suppress melatonin as well. Melatonin suppression continues at decreasing rates as wavelengths become longer or shorter than the 480 nm peak.
If you want maximum protection, you’ll also want to block a substantial portion beyond 480 nm.
With that being said, here are my recommendations for the best glasses.
Glasses to suppress blue light's effect on circadian rhythms
These glasses block the most blue light and are the ones to wear leading up to your ideal sleep time. For a dayshift schedule, this means putting them on after sunset, or two to three hours before bed.
For night shift, wear them for at least the last couple hours, if not the last half of your shift, and don’t take them off until you’re in bed with the lights out. Light exposure during the latter part of the night and early morning causes a phase advance of your circadian rhythm – something you’ll want to avoid to increase your chance of quality sleep.
My personal choice for blue-light-blocking glasses is BON CHARGE. Their glasses have been tested to block 100% of the wavelengths below 550 nm. They come in a wide range of stylish frames and are available with prescription lenses.
Offered in a variety of styles and tested by a third party laboratory, Night Swannies block over 99% of blue light up to 490 nm, and over 98% up to 500 nm.
Swanwick Sleep also offers prescription lenses, as well as fit over glasses.
The BioRhythm Safe glasses block 99.8% of light between 450 and 510 nm.
Note: If you work a permanent night shift schedule, you may want to forgo blue-light-blocking glasses during the shift, wearing them only on the commute home and before bed. This is because you’re baseline melatonin profile may be such that peak levels occur during the daytime sleep period. Though my recent article on permanent night work explains why this is unlikely.
Will wearing blue-light-blocking glasses during night shift affect performance?
I initially assumed wearing these glasses during night shift work could cause problems, but a study from The Journal of Clinical Endocrinology & Metabolism suggests otherwise. In fact, participants in the study wore glasses that filtered out all light below 530nm for the entirety of their night shifts, without any adverse effect on attention span, concentration, or response accuracy.7
“strategies designed to preserve normal melatonin secretion produce few, if any, impairments in neurobehavioral functions and are unlikely to negatively affect on the job performance.”7
What if I require safety glasses?
The Skyper by Uvex meets ANSI and CSA standards in addition to blocking 98% of all blue-light.
Uvex also provides safety glasses designed to fit over your prescription glasses.
Important note: Do not wear glasses from the above category while driving. Quality blue-light-blocking glasses can make it difficult to recognize traffic lights, road signs, and potential hazards. For this you’ll want to grab the pair below.
Glasses to wear when driving home after night shift
When commuting during daylight, you want to prevent the sun from advancing your circadian rhythm and making it harder for you to sleep. The solution is sunglasses that are also blue-light-blocking (most aren’t).
The best lenses for driving are grey and brown (with polarization), as they are colour neutral.
The Espresso lens by Uvex fits this criteria as it is colour neutral, has about 12% light transmission, and also filters 97% of blue light. In fact this is the exact lens used by researchers at the Biological Rhythms Research Laboratory at RUMC in Chicago.8
The Uvex Espresso comes in multiple styles and is also ANSI and CSA approved.
Glasses that block blue light that are also driving approved seem to be hard to find. This is why I recommend the UVEX for this purpose.
A search on Amazon will turn up other options. For example, this pair from BluBlocker is polarized and supposedly blocks 100% of light below 500 nm. However customers have noted that green traffic lights appear dim, making them harder to see. One customer also noted that “general driving awareness” was different.
For a more in-depth look at how light affects our health and circadian rhythms, including even more tips for protecting yourself, check out What is blue light, and why is it harmful?
- doi.org/10.1111/opo.12385[↩]
- ncbi.nlm.nih.gov/pubmed/19637050[↩]
- ncbi.nlm.nih.gov/pubmed/30700675[↩]
- ncbi.nlm.nih.gov/pmc/articles/PMC5602660[↩]
- ncbi.nlm.nih.gov/pmc/articles/PMC4989256[↩]
- ncbi.nlm.nih.gov/pmc/articles/PMC3020104[↩]
- doi.org/10.1210/jc.2004-2062[↩][↩]
- ncbi.nlm.nih.gov/pmc/articles/PMC3841977[↩]