Blue light-filtering glasses—commonly referred to as blue light glasses—are touted for their supposed ability to combat the physical consequences of excessive screen time. The glasses have been become a popular purchase, especially since the pandemic, to reduce blue light exposure that comes from computers, tablets and iPhones.

According to Harvard Medicine, blue light can help boost focus and mood during the day but can disrupt sleep at night and suppress the release of melatonin—the sleep hormone. Blue light has also been blamed for eye strain and discomfort. As a result, people have been shelling out for blue light-filtering spectacles in hopes of snoozing in peace and reducing visual fatigue. Even though sunlight is the primary source of blue light, our excessive digital diets have made people wary of their levels of blue light exposure.

But new research says the suggested benefits of blue light glasses are fuzzy.

In an analysis of 17 randomized control trials from six countries, published in the Cochrane Database of Systematic Reviews on August 17, researchers found blue light glasses may not improve visual fatigue compared to glasses that do not filter out blue light; conclusions could not be drawn about their impact on sleep or daytime alertness.

“Over the past few years, there has been substantial debate about whether blue-light filtering spectacle lenses have merit in ophthalmic practice. Research has shown that these lenses are frequently prescribed to patients in many parts of the world and a range of marketing claims exist about their potential benefits,” Laura Downie, PhD, author of the study and head of the Downie Laboratory: Anterior Eye, Clinical Trials and Research Translation Unit, at the University of Melbourne, Victoria, Australia, said in a press release. “The outcomes of our review, based on the current, best available evidence, show that the evidence is inconclusive and uncertain for these claims.”

While optimizing our health and performance is top of mind for many, the glasses might not be worth the money. Downie hopes professionals and consumers take note, adding that as a result of the findings, she does not endorse prescribing blue light glasses to the general public.

Downie also says it is “unclear” whether blue light glasses impact vision and sleep quality, as well as long-term retinal health. There was also a lack of information about the differences between the glasses regarding contrast sensitivity, color discrimination, discomfort glare, macular health, serum melatonin levels, or overall patient visual satisfaction.

The evidence is blurry

A 2021 article on the The American Academy of Ophthalmology website says, “there is no scientific evidence that blue light from digital devices causes damage to your eye.” The article adds that the eye strain many of us feel is probably tied to digital strain because we tend to blink less when scrolling, according to Dr. Rahul Khurana, a spokesperson for The American Academy of Ophthalmology.

Ways to reduce eye strain

Experts say there are ways to improve visual comfort without the glasses: Vary the types of things you are focusing on, or your field of vision. Looking at a computer all day only engages a specific part of your vision. It’s also important to blink and try the “20-20-20” rule: every 20 minutes, look at an object 20 feet away for 20 seconds.

Limit screen time overall, and dim the brightness levels when you can.

No harm, no foul

While researchers found no notable benefits to blue-light glasses, they didn’t find any key harmful consequences of using them either (besides the potential headaches and discomfort associated with wearing glasses in general). However, a key limitation is the duration of the trials, with assessment between one day to five weeks after wearing either the blue light or non-blue light glasses. The sample sizes also ranged from five to 156 per trial. Due to this, the team only made conclusions about short-term use.

The researchers hope to conduct further research on the effects of blue light glasses on sleep, eye health, and more, Dr. Sumeer Singh, an author on the study from the Downie Laboratory, said in the press release.

“They should examine whether efficacy and safety outcomes vary between different groups of people and [use] different types of lenses,” he said.