Many of us assuage our guilt over maxed-out screen times and scrolling before bed by wearing blue light-filtering glasses. But do they make a difference? Probably not, say scientists in a new review of available evidence.
Blue light is a prominent part of the visible light spectrum but is also emitted by artificial sources like phones and computers.
Optician-recommended blue light filters have been rising since the early 2000s. Marketing claims suggest that they reduce the eye strain and sleep disruption caused by excessive blue light.
But scientists from the University of Melbourne, Australia as well as the University of London and Monash University, Australia, have reviewed 17 randomised control trials to find out whether blue light filters really make any difference.
The answer? They found that it’s likely that the lenses in fact make no difference to eye strain or sleep quality caused by screens whatsoever – at least in the short term.
The team also found no evidence that the lenses protect against damage to the retina (the part of your eye which takes light and turns it into signals for your brain). This is partly explained by the fact the original studies did not evaluate this.
“This review is fairly damning,” said Prof Andrew Przybylski from the University of Oxford – who was not involved in the review. “It provides the public an opportunity to pause and ask themselves if they really should be changing their behaviour or buying things to address what they fear are problems of the digital age.”
According to the researchers, the amount of blue light our eyes receive from artificial sources like phones and computer screens is only around one-thousandth of what comes from natural daylight. What’s more, the lenses only block out 10-25 per cent of blue light.
“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,” said first author Dr Sumeer Singh.
Senior author Prof Laura Downie of the University of Melbourne added: “People should be aware of these findings when deciding whether to purchase these spectacles.”
However, since the review only looked at short-term studies with timescales between one day to five weeks, more research is needed to determine the lenses’ effectiveness in the longer term.
Singh called for “high-quality, large clinical research studies with longer follow-up in more diverse populations” to get a clear answer on whether there are any benefits of blue light filters – and whether these apply to everyone.
But if you already wear them, don’t worry. The studies didn’t find any negative side effects of wearing these lenses beyond those usually associated with wearing glasses, such as discomfort and headaches.
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