Many of us are constantly attached to our screens daily – but do glasses marketed to block blue light from screens really protect our eyes?

Glasses that claim to block blue light might not have a significant impact on eye strain from computer use or on the quality of sleep, a recent Cochrane review suggests.

An in-depth study, evaluating 17 randomized controlled trials, found no conclusive evidence supporting the benefits of such glasses. Furthermore, the review did not find evidence that these lenses offer protection against retinal damage, an outcome not assessed in the included studies. Since the early 2000s, these blue-light-blocking glasses have gained popularity, with many optometrists recommending them.

This comprehensive review, featured in the Cochrane Database of Systematic Reviews, was a collaborative effort of researchers from the University of Melbourne, City, University of London, and Monash University.

The research team sought to understand the effects of these lenses in terms of visual performance, retinal protection, and sleep quality improvement. The 17 trials analyzed came from six countries, with study sizes ranging from five to 156 participants and durations varying from a single day to five weeks.

Associate Professor Laura Downie, senior author of the review from the University of Melbourne, remarked, “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. 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. People should be aware of these findings when deciding whether to purchase these spectacles.”

However, Professor Downie also emphasized the importance of understanding the limitations of these studies.

“We performed the systematic review to Cochrane methodological standards to ensure the findings are robust. However, our certainty in the reported findings should be interpreted in the context of the quality of the available evidence. The short follow-up period also affected our ability to consider potential longer-term outcomes,” she added.

Dr. Sumeer Singh, the review’s first author, remarked that further high-quality, extended research is necessary to conclusively understand the effects of blue-light filtering glasses.

Surprisingly, the review did not reveal consistent reports of side effects from these glasses. Any reported effects were mild and transient, including discomfort, headaches, and mood dips. Such effects are likely tied to wearing glasses in general.

Professor Downie expressed, “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, including that they may reduce eye strain associated with digital device use, improve sleep quality and protect the retina from light-induced damage.

“The outcomes of our review, based on the current, best available evidence, show that the evidence is inconclusive and uncertain for these claims. Our findings do not support the prescription of blue-light filtering lenses to the general population. These results are relevant to a broad range of stakeholders, including eye care professionals, patients, researchers, and the broader community.”

The exact reasons for the potential benefits of these glasses remain speculative. One argument is that modern digital devices emit more blue light than older sources, and their usage has increased, especially closer to bedtime.

Dr. Singh noted, “The amount of blue light our eyes receive from artificial sources, such as computer screens, is about a thousandth of what we get from natural daylight. It’s also worth bearing in mind that blue-light filtering lenses typically filter out about 10-25% of blue light, depending on the specific product. Filtering out higher levels of blue light would require the lenses to have an obvious amber tint, which would have a substantial effect on colour perception.”

Source: 10.1002/14651858.CD013244.pub2

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