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Blue-light-filtering glasses improve sleep and performance at work the next day

Photo by nacer eddine on Unsplash.

Do you feel like you might be getting too much screen time these days? Pinned down, as we are, by the pandemic, many of us are overdosing on doom-scrolling, Zoom-gazing and Netflix-binging—behavior that makes it more difficult to get a good night’s sleep.

But wearing glasses that filter out blue light can lead to sounder sleep and a more productive workday, according to new research co-authored by Christopher Barnes, a professor of management and Evert McCabe Endowed Fellow at the University of Washington Foster School of Business.

“Blue-light-filtering glasses create a form of physiological darkness, thus improving both sleep quantity and quality,” says Barnes, who studies the many workplace ills produced by employee fatigue. “Better sleep leads to improved productivity, engagement and social behavior at work, and reduces counterproductive and unethical behaviors.”

Blue light special

Most of the technology we take for granted in everyday work and life—smartphones, tablets, laptop computers—emits blue light, a particular wavelength on the visible spectrum that is known to disrupt sleep cycles when absorbed too close to bedtime.

That’s exactly what’s happening to us… increasingly. In normal times, we work at screens throughout the day and stare at them well into the evening. Extended screen time during the isolation of the COVID-19 pandemic has only increased our exposure to this problematic hue of visible light.

Fortunately, blue-light-filtering glasses and screens have been shown to mitigate the harmful effects of excessive screen time at the wrong time. They facilitate a better night’s sleep.

But do the benefits of blue-light filters continue into the workday? And do they affect everyone equally?

Protecting circadian cycles

To find out, Barnes collaborated with Cristiano L. Guarana of Indiana University’s Kelley School of Business, a graduate of Foster’s PhD Program, and Wei Jee Ong, a current doctoral student at the Foster School.

Chris Barnes

In two studies, Barnes and his colleagues measured the performance of managers and call center employees at a multinational financial firm who were asked to wear identical-looking glasses that either filtered blue light or did not (they didn’t know which).

Blue-light-filtering glasses delivered discernible benefits to their wearers: better sleep quality and quantity, as well as improved productivity, attitude and social behavior in the workplace.

Finally, the researchers measured these variables through the context of circadian rhythm—the internal process that regulates our sleep-wake cycle, repeating roughly every 24 hours. Not everyone’s circadian cycles align, which is why some of us tend to be night owls and other morning larks. This is known as our “chronotype.”

Noting the chronotype of each study participant, the study produced some evidence that night owls benefit most at work from wearing blue-light-filtering glasses. Barnes explains that this is because night owls tend to experience the greatest misalignment between their internal clock and their work schedule. They are most likely to start an early workday on the groggy side.

Inexpensive productivity boost

Barnes notes that the study’s finding is important because blue-light exposure can have a cumulative effect on performance, at least in the short term. The more consecutive poor sleeps, the worse a person performs.

“Blue-light exposure should be of concern to organizations,” says Guarana. “The ubiquity of the phenomenon suggests that control of blue-light exposure may be a viable first step for organizations to protect the circadian cycles of their employees from disruptions.”

Since nighttime screen time is a habit that is hard to break, distributing blue-light-blocking lenses to employees for home use could be an inexpensive strategy to boost productivity—especially in pandemic times.

“This study provides evidence of a very cost-effective means of improving employee sleep and work outcomes, and the implied return on investment is gigantic,” adds Barnes. “I do not know of any other interventions that would be this powerful at such a low cost.”

The Effects of Blue-Light Filtration on Sleep and Work Outcomes” is published online in the Journal of Applied Psychology.