Scientists have long known there’s a link between sleep and work performance, with a lack of quality shut-eye shown to cause fatigue, low energy, and poor focus. Now, a new study has shown that enjoying a better night’s sleep and boosting your performance at work could be as simple as wearing a pair of blue light filtering glasses.

Most of the technology we use at home and in the office such as smartphones and all sorts of screens emit blue light that can disrupt sleep, according to previous studies. The pandemic has made us more dependent on all these devices as we moved from going to the office or to school to doing everything from home.

The media has recently described the benefits of blue-light glasses for those spending a lot of time in front of a computer screen. This topic is the focus of the new research, extending our understanding of the circadian rhythm, a natural and internal process that regulates the sleep-wake cycle and repeats roughly every 24 hours.

“We found that wearing blue-light-filtering glasses is an effective intervention to improve sleep, work engagement, task performance and organizational citizenship behavior, and reduced counterproductive work behavior,” said Cristiano L. Guarana, co-author, in a statement. “Wearing blue-light-filtering glasses creates a form of physiologic darkness.”

The researchers collected data from 63 company managers and 67 call center representatives at the Brazil offices of a U.S. multinational financial firm and measured task performance from client feedback. Participants were randomly chosen to test glasses that filtered blue light or normal glasses.

In the week they wore blue glasses, customer service representatives slept 6% longer, improved the quality of their sleep by 11%, and improved their task performance by 9%. They also increased their work engagement by 8.25%, their helping behavior by 18%, and decreased their negative work behavior by 12%.

Similar results were found in call center representatives. They slept 5% longer, improved the quality of their sleep by 14%, and improved their task performance by 7%. Their work engagement increased by 8.5%, their helping behavior by 17% while decreasing their negative work behavior by 12%.

“We have clear evidence that all of those outcomes were improved merely by wearing these glasses,” said Cristopher Barnes, co-author, in a statement. “Most organizations, if they had just made a large financial investment on an expensive performance improvement program and they got a 9% improvement (on task performance) as an outcome, they would be ecstatic.”

Thankfully, a lot of companies are already offering solutions. From cheap, brandless options to Versace sunglasses, blue light-blocking glasses have become relatively common as scientists have raised concerns about blue light. Even some creams are advertised with the same purpose, though the health benefits of such products are less clear.

A 2019 report by France’s Agency for Food, Environmental and Occupational Health & Safety (ANSES) found adverse effects of blue LED light on the eye, which, in time, can lead to impaired vision. So it makes sense, if blue light is stressful on the eye, that blocking it may help the wearer relax and sleep better.

“Specifically, we theorize that wearing blue-light filtering glasses creates a form of physiologic darkness, thus improving both sleep quantity and quality. We then argue that wearing blue-light filtering glasses is related to work engagement, task performance, and non-task performance via sleep quantity and sleep quality,” the researchers conclude.

The study was published in the journal Applied Psychology.