The effectiveness of blue-light filtering spectacles marketed to reduce eye strain caused by computer use and improve sleep quality has been called into question by a comprehensive review of 17 randomized controlled trials, representing the most robust evidence available to date. The review, published in the Cochrane Database of Systematic Reviews, was conducted by researchers from the University of Melbourne, City, University of London, and Monash University.
Blue-light filtering lenses, also known as blue-light blocking spectacles, have gained popularity and have often been prescribed or recommended, particularly by optometrists, since the early 2000s. These lenses are designed to filter out blue light, which is emitted by modern digital devices like computers and smartphones and is believed to contribute to eye strain and sleep disruption.
According to The Washington Post, the study aimed to assess the effects of blue-light filtering lenses in comparison to non-blue-light filtering lenses regarding visual performance improvement, retina protection, and sleep quality enhancement. Data from 17 trials from six countries were analysed, with participant numbers ranging from five to 156, and the assessment period spanning from less than one day to five weeks.
The findings revealed that blue-light filtering lenses may not provide short-term advantages in reducing visual fatigue associated with computer use, compared to non-blue-light filtering lenses. The review also highlighted uncertainties about the impact of these lenses on vision quality, sleep outcomes, and potential effects on retinal health over the longer term.
Associate Professor Laura Downie, the senior author of the review and Head of the Downie Laboratory: Anterior Eye, Clinical Trials and Research Translation Unit at the University of Melbourne, emphasized the importance of the findings for potential purchasers of these spectacles. She suggested that individuals should be aware of the lack of short-term advantages and the uncertainty surrounding other potential effects when considering whether to invest in blue-light filtering lenses.
The review did not identify consistent reports of adverse side effects associated with the use of these lenses. Any reported effects tended to be mild, infrequent, and temporary, like those experienced with non-blue-light filtering lenses. While acknowledging the rigorous methodology used in the review, Professor Downie highlighted the need to consider the quality and duration of the studies included. She underlined that high-quality, long-term clinical research studies involving diverse populations are necessary to provide more definitive insights into the potential impacts of blue-light filtering lenses on visual performance, sleep, and eye health.
The research community, eye care professionals, patients, and the broader public should pay heed to the inconclusive nature of the evidence presented in the review. The uncertainty around the efficacy and safety of blue-light filtering lenses emphasizes the need for further research to discern the potential benefits or drawbacks of these products in various contexts and for different groups of people.
The underlying mechanisms by which blue-light filtering lenses might alleviate eye strain, enhance sleep, and safeguard retinal health remain unclear. Claims about the lenses’ benefits are rooted in the notion that modern digital devices emit more blue light than traditional lighting sources, and are used for extended periods, often closer to bedtime.
Dr. Sumeer Singh, the first author of the review and a postdoctoral research fellow in the Downie Laboratory, highlighted that the amount of blue light from artificial sources, such as screens, is significantly lower than natural daylight exposure. Furthermore, blue-light filtering lenses typically only filter out around 10-25% of blue light, depending on the product, and filtering out higher levels would result in lenses with a noticeable amber tint, which could impact colour perception.
The review casts doubt on the claimed benefits of blue-light filtering lenses for reducing eye strain, enhancing sleep quality, and protecting the retina. The inconclusive evidence underscores the need for further comprehensive and long-term research to provide a clearer understanding of the potential effects of these lenses. As the debate on the merits of blue-light filtering lenses continues, individuals and professionals should consider the current uncertainties before making decisions related to their use.
