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Screens, Blue Light and Poor Sleep: Still Debated Links

Of the many reasons that can hamper your daily productivity, poor sleep is at the top of the list. But is poor sleep connected to the constant use of technology?  This is is still a point for debate.

Those incessantly glued to a screen before bedtime for either work or personal reasons – for some, an inevitable event during the pandemic, when most communication is via a screen, could be losing sleep because of blue light.

Blue light coming from phones, tablets and laptops could reduce the quality of sleep, making us grouchy, snappy and less produtive. 

All light sources, even  fluorescent bulbs and LED lights, emit blue light that can throw the human body off its natural internal clock, known as the circadian rhythm. This happens because our brain perceives the presence of bright light indoors as daylight and stops the release of the melatonin hormone, responsible for regulating the body’s 24-hour sleep-wake cycle.   

An easy, low-cost solution to restore one’s disrupted sleep cycle, as suggested by a new study, is to wear glasses that filter blue light before those short, high energy wavelengths reach the retina. Glasses that block blue light are aplenty, online and in stores.

But whether blue-light blocking lenses work is still a question. A new study shows it does; others, such as this  2017 review, do not.

New Study

In a study published in the Journal of Applied Psychology ,researchers at the Indiana University (IU) Kelley School of Business and the University of Washington (UW) Foster School of Business discovered that filtering blue light is crucial to a good night’s rest, improving work performance the next morning. 

Two US multinational companies based in Brazil, one with 63 workers in managerial roles and another with 67 call center employees, tested blue-light filtering eye gear. Half the participants were randomly assigned the filtering glasses. They were told to wear them for one week. Each night they wore them for two hours before going to sleep. The other half were given placebo glasses, which looked similar but had no light-filtering lenses. 

Managers Slept Better With Blue-Light Filtering Glasses

In comparison to those who wore the placebo glasses, the managers reported sleeping 5% longer with 14% higher quality of sleep after wearing blue-light filtering glasses. This had a positive impact on how the managers fared at work and interacted with coworkers.

The survey found that managers who wore the glasses showed 8.51% more engagement with work and 17.29% more helping behavior than usual, while their negative attitude was cut by 11.78%. 

The glasses helped because blue light has the strongest effect on the eyes, unlike all other light, said study co-author Christopher M. Barnes, PhD, professor of management at the UW business school, in a news release.

“So, filtering out blue light eliminates much of the suppressing effect of light on melatonin production, allowing the evening increase in melatonin to occur and thereby enabling the process of falling asleep,” Dr. Barnes said.

Call Center Workers Improved Customer Satisfaction

The study participants who worked in the call center said wearing the blue-light dimming glasses helped them sleep better, too, compared to the placebo-wearers. They reported sleeping 6% longer and 11% better.

The call center workers also showed 8.25% higher engagement levels at work. They became 17.82% more helpful, which in turn reduced negative work behaviors by 11.76%. There was also an increase in customer ratings: a 9% rise, compared to participants who wore the placebo glasses.

Call center workers have more to gain by blocking blue light because they often work late into the early hours of the morning. The researchers found that the glasses are more helpful to people who stay up late than to morning larks, who go to bed early and rise early.

“Although most of us can benefit from reducing our exposure to blue light, owl employees seem to benefit more because they encounter greater misalignments between their internal clock and the externally controlled work time,” Cristiano L. Guarana, assistant professor in the Department of Management and Entrepreneurship at the IU business school, said in the  news release.

Other Studies Aren't as Sure

The 2017 review differs from the above findings. The review states that there is “a current lack of high quality clinical evidence to support a beneficial effect with blue ‐ blocking spectacle lenses for reducing eye fatigue.”

Other researchers are in agreement. Amir Mohsenin, MD, PhD, assistant professor in the Ruiz Department of Ophthalmology and Visual Science at McGovern Medical School in Houston, said he doesn’t believe that blue-light glasses help at all.

“We don’t really have any data that supports blue blocking glasses as being better for your eyes when you’re using a computer. In fact, I would say that we don’t know if there’s any potential harm in wearing blue block glasses. It’s hard to recommend something without knowing more details about it,” Dr. Mohsenin said in a January press release from the Texas Medical Center in Houston. 

The take-home

Purchasing blue glasses at prices ranging from $10 to $100 may not help, according to the Cleveland Clinic.

Rishi Singh, MD, an ophthalmologist at the Cleveland Clinic Cole Eye Institute in Ohio, said that digital eyestrain can be caused by a variety of reasons, including not blinking enough when staring at a screen. Dr. Singh suggested sitting 25 inches away from the screen. He also recommended the “20-20-20” rule: Break eye contact with the screen every 20 minutes for 20 seconds and focus on something at least 20 feet away.

When we focus our eyes on something close up, like a screen or even a book, our eyes are strained and contracted, which can cause eye discomfort. But if you look ahead to a distant object, our eyes relax,” Dr. Singh said. 

 

Seema Prasad is a freelance health reporter based in Bengaluru, India. She tweets  @SeemaPrasad_me

 

 

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