Blue-light filtering lenses, also known as blue-light blocking spectacles, have been increasingly prescribed or recommended, often 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.
Are Blue Light-Blocking Glasses Worth the Hype?
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 a reduction in eye strain associated with digital device use, improved sleep quality, and protection of the retina from light-induced damage.
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In the search to find the scientific evidence for blue light filtering glass benefits, researchers set out to assess the effects of blue-light filtering lenses compared with non-blue-light filtering lenses for improving visual performance, providing protection to the retina, and improving sleep quality.
They analyzed data from all the randomized controlled trials they could find on the topic and found 17 trials from six countries. The number of participants in individual studies ranged from five to 156, and the period over which the lenses were assessed ranged from less than one day to five weeks.
Blue-Light Filtering Spectacles Fizzle in Delivering Promised Benefits
They found there may be no short-term advantages to 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, the quality and duration of the studies also need to be considered. The 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.
High-quality, large clinical research studies with longer follow-ups 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.
The review did not find any consistent reports of adverse side effects from using blue-light filtering lenses. Any effects tended to be mild, infrequent, and temporary. They included discomfort wearing the spectacles, headaches, and lower mood. These were likely to be related to the wearing of spectacles generally, as similar effects were reported with non-blue-light filtering lenses.
The potential mechanisms by which blue-light filtering lenses might be able to help with eye strain, sleep, and protecting the retina are unclear. One basis for claims about the benefits of these lenses is that modern digital devices such as computers and smartphones emit more blue light than traditional lighting sources and are being used for longer, and closer to bedtime().
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 is 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 color perception.
References:
- Vagge, Aldo et al. Blue light filtering ophthalmic lenses: A systematic review. Seminars in ophthalmology vol. 36,7 (2021): 541-548.(https://www.tandfonline.com/doi/abs/10.1080/08820538.2021.1900283?journalCode=isio20)
- Singh, Sumeer et al. Do Blue-blocking Lenses Reduce Eye Strain From Extended Screen Time? A Double-Masked Randomized Controlled Trial. American Journal of Ophthalmology vol. 226 (2021): 243-251.(https://www.ajo.com/article/S0002-9394(21)00072-6/fulltext)
- Bigalke, Jeremy A et al. Effect of evening blue light blocking glasses on subjective and objective sleep in healthy adults: A randomized control trial. Sleep Health vol. 7,4 (2021): 485-490.(https://www.sciencedirect.com/science/article/abs/pii/S2352721821000127?via%3Dihub)
Source: Eurekalert
