How Do Blue Blockers Work?

The Science of Blue Light

There's no replacing a good night's sleep. Drowning yourself in coffee may get you through your day, but caffeine and other stimulants simply can't provide the restorative effects offered by proper rest. That's why it's all the more concerning that a growing number of adults don't get enough sleep.

A 2016 study suggested that more than a third of American men and women fail to rest for the recommended seven hours a day, a shortcoming that can lead to chronic conditions ranging from high blood pressure to heart disease.

That same study found that the increasing prevalence of blue light in our day to day lives - that is, the kind emitted by electronic devices such as phones and computers - is partly to blame for that phenomenon, as exposure to it during nighttime hours has been linked to sharply lowered levels of melatonin production (the hormone necessary for healthy, regular sleep). Though it's easy to say that we all should simply try to avoid using those devices after dusk, that's easier said than done for those of us who work the night shift or who rely on technology to remain connected to our friends and family. What, then, is the solution?

How Blue Blockers Work

Before we can understand why it's important to shield our eyes from blue light, we must first understand the specifics of how it lessens melatonin production and affects our sleep. In this sense, the main issue is in how blue light interacts with the photosensitive retinal ganglion cells (pRGCs) found within our eyes. These cells hold a direct line to the suprachiasmatic nucleus (SCN), which governs the circadian rhythm of our bodies - in part by sending signals to the pineal gland concerning its production of melatonin.

Put simply, the stimuli experienced by pRGCs dictates much of the SCN's behavior in this regard. When these cells are exposed to blue light, they tell the SCN to tell the pineal gland to limit or halt the production of melatonin. Though researchers are still unsure as to why pRGCs react in this way to light on that wavelength, some have suggested that the cells' behavior is dictated in part by the blueness of the daytime sky. pRGCs, after all, cannot distinguish between natural and artificial light. When they're exposed to stimuli similar to that provided by a clear daytime sky, it only makes sense that they would tell the SCN to hold off on the production of sleep-spurring hormones - as far as they know, it's nowhere near yet time to go to bed.

If you simply cannot lessen your exposure to blue light after dusk, the next best step you can take is to prevent that light from affecting your eyes. That's where blue blockers (also known as sleep glasses) come in. The tint of their amber lenses are designed specifically to block light on the blue portion of the spectrum before it can reach your retinas, thus lessening the effects it can have on melatonin production. Though this may seem like an overly-simple solution, research has borne out the effectiveness of blue light blocking glasses in maintaining proper melatonin production and healthy sleep. A 2006 study, for example, found blue blockers to be "an elegant means to prevent the light-induced melatonin suppression."

For the Night Shift

Though all individuals can be affected by the issues related to a lack of healthy sleep, those issues are much more pronounced among those who typically work during nighttime hours. A 2009 study, in fact, suggests that night shift workers are at a nearly three-fold greater risk for occupational accidents than those who work during the day, a phenomenon that has been attributed in part to these individuals' exposure to blue light after dusk. Maintaining a healthy sleep cycle while working a third-shift job is tough enough on its own - the task only becomes tougher when your body refuses to produce the melatonin needed for a good night's (or day's, in this case) rest. 

Thankfully, researchers have discovered that blue blocking glasses can be tremendously helpful in maintaining proper melatonin production for these individuals. That was the conclusion reached by a 2005 study, which also indicated that night-shift workers who made use of blue blockers experienced no adverse effect on their work. "The blocking of short-wavelength light does not interfere with attention span, concentration, or response accuracy," the authors of that study wrote. "These findings suggest that 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.”

For the Technophile

As much as we love our smartphones, computers, and other electronic devices, the sad truth is that the blue light they emit can curb melatonin production when viewed after dusk. This phenomenon has become something of an epidemic in recent years as technology has become more portable and more prevalent - a 2015 report, for example, suggested that 71 percent of Americans sleep within a few feet of their smartphone. That proximity indicates that many of those individuals made use of the device while winding down for bed, a practice that in truth will only encourage more tossing and turning - and, in turn, more midnight browsing or app usage, which serves only to perpetuate the cycle of fatigue. Though technology addiction is a significant issue in its own right, you don't have to exacerbate the problems it can cause by allowing your devices to mess with your much-needed rest. Wearing blue light blockers while making use of smartphones or similar devices at night can help ensure that your level of melatonin production remains normal, even if you're tied to your technology right up to the moment when you close your eyes.

The lack of healthy sleep is nothing less than a national epidemic, a crisis that costs us billions a year in medical costs and steals both time and health from individuals across classes and localities. Wearing blue blockers may seem like a small and simple step, but it's an important one for those of us whose healthy sleep has been disrupted and limited by exposure to blue light. If you'd like to learn more about the technology behind blue blockers - or about all the ways in which quality eyewear can promote long-term health - please feel free to send us an e-mail or to give us a call at (818) 232-2556.