Blue light glasses gained popularity over the past few years with the idea they protect our eyes against screen usage — but a new analysis shows they might not be as beneficial to our eye health as previously hoped.

Researchers reviewed data from 17 randomized controlled trials — the "current, best available evidence" they could find on the topic — and published the results Friday in the Cochrane Database of Systematic Reviews journal. The findings? Glasses marketed to filter out blue light probably make no difference to eye strain or sleep quality. 

"We found there may be no short-term advantages with using blue-light filtering spectacle lenses to reduce visual fatigue associated with computer use, compared to non-blue-light filtering lenses," said Laura Downie, senior author of the review and associate professor at the University of Melbourne, Victoria, Australia, in a news release. 

"It is also currently unclear whether these lenses affect vision quality or sleep-related outcomes, and no conclusions could be drawn about any potential effects on retinal health in the longer term," she added. "People should be aware of these findings when deciding whether to purchase these spectacles."

The studies they reviewed ranged in size and length, with a span of as few as five to as many as 156 participants assessed over different periods, from less than one day to five weeks. The authors said more research with longer follow-ups in more diverse populations are needed to better assess any potential effects.

"(More studies) should examine whether efficacy and safety outcomes vary between different groups of people and using different types of lenses," author Dr. Sumeer Singh, a postdoctoral research fellow in the Downie Laboratory, advised for future research. 

Blue light, like that emanating from computer screens and smartphones, does stimulate the eyes, something that can cause sleeping problems. During the pandemic, doctors reported seeing an uptick of vision issues related to computer use including eye strain, which can lead to headaches, frontal headaches, pain around the eyes and pain behind the eyes, as well as dry eyes and related problems.

Americans were also worried about how increased screen time during lockdowns would impact their eyes. A July 2020 Alcon/Ipsos survey found 60% of people said they were concerned about the potential impact.

Sellers of blue light blocking glasses or filters promised a solution — but this isn't the first time experts have shown skepticism about their effectiveness.

Earlier this year, optometrist Dr. Robert Johnson told CBS News Pittsburgh that, while he is concerned about the impact of screens on our vision, blue light blockers aren't the answer. 

"I would have patients coming in saying they just ordered blue-blocking glasses from the internet for their daughter and what was my opinion," he said. "This blue-blocking situation has been bogus basically from the get-go. ... It's one of the absurdities that come from advertising."

But while blue light blockers may not do anything, they won't hurt you. In fact, he said, "it causes absolutely no damage."

Instead of shelling out money for special shades, however, experts advise taking screen breaks. 

Dr. Christopher Starr, an ophthalmologist at Weill Cornell Medicine in New York, previously told "CBS This Morning" that those glasses aren't needed as much as small breaks away from staring at the screen.

"Taking breaks is important, and I think that's the real key here, not so much glasses or filters over your screens," Starr said.

He recommends small breaks away from screens every 20 minutes. During that break, look into the distance at an object at least 20 feet away or farther, for 20 seconds or more. Also shut your eyes for 20 seconds during the break.

Johnson also goes by the "20-20-20 rule."

"For every 20 minutes, look away in excess of 20 feet for 20 seconds," he said. "That will relax your focusing mechanism that will give your eyes a break and that will make you more comfortable." 

-John Shumway and Analisa Novak contributed to this report.

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