A systematic review into blue-light filtering lenses in glasses has found the popular feature is unlikely to reduce eye strain associated with digital device use in the short-term, undermining claims of their potential benefits.
The review of 17 randomised controlled trials, led by University of Melbourne researchers and published in the Cochrane Database of Systematic Reviews, found clinical evidence did not support claims that blue-light filtering lenses impact sleep quality, or protecting against damage to the retina.
The ‘short-term’ timeframe for evaluating the interventions ranged from two hours to one week of use.
While digital devices with screens, including computers, tablets and phones all emit some degree of blue light, claims that blue-light filtering lenses, often called ‘blue-blocking’ lenses, reduce digital eye strain have been questioned.
The research team analysed data from studies performed in six countries, which included a total of 619 people.
Review senior author, University of Melbourne Associate Professor Laura Downie, Head of the Downie Laboratory: Anterior Eye, Clinical Trials and Research Translation Unit, said the findings have implications for eye care professionals and consumers.
“We found there may be no short-term advantages with using blue-light filtering spectacle lenses to reduce eye strain associated with computer use, compared to non-blue-light filtering lenses,” Associate Professor Downie said.
“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 spectacle lenses.”
Associate Professor Downie said the lenses are often prescribed to patients and that many marketing claims exist about their potential benefits, which patients can find confusing.
“The outcomes of our review, based on the current, best available evidence, show that the evidence is inconclusive and uncertain for these claims,” she said.
“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.”
Review first author, University of Melbourne Dr Sumeer Singh, a postdoctoral research fellow in the Downie Laboratory, said: “High-quality, large clinical research studies with longer follow-up in more diverse populations are still required to ascertain more clearly the potential effects of blue-light filtering spectacle lenses on visual performance, sleep and eye health.”
“They should examine whether efficacy and safety outcomes vary between different groups of people and using different types of lenses.”
Dr Singh said the amount of blue light our eyes receive from artificial sources, such as computer screens, is about one 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 per cent 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,” Dr Singh said.
The research was undertaken in collaboration with colleagues at City, University of London and Monash University.