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Jul 03, 2023

Glasses with blue light filters don’t protect wearer’s eyes, study suggests

Claims tinted lenses reduce eye strain, protect the retina and help with sleep not backed up by research studies Paying £30 to upgrade a pair of standard spectacles so they have a blue light filter on

Claims tinted lenses reduce eye strain, protect the retina and help with sleep not backed up by research studies

Paying £30 to upgrade a pair of standard spectacles so they have a blue light filter on them is a waste of money as the tint does nothing to protect the wearer’s eyes, a scientific review has suggested.

Blue light filters have become increasingly popular recently following claims they prevent strain on the eyes caused by staring at computer screens and other devices.

The evidence has long been flimsy and the subject of debate. Now a gold-standard review of 17 leading trials has found the blue light lenses are ineffective.

Scientists gathered the best available data from a host of studies which followed people over time and found blue light lenses provide no benefit.

“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,” said Prof Laura Downie, review author from the University of Melbourne.

The scientists found the data that existed on the purported benefits of blue light lenses were of little credibility.

When held to the high standards of a Cochrane review - the highest standard in evidence-based health care - the team found they were unable to draw strong conclusions because the data was so weak.

Despite long-held uncertainty over the efficacy of the lenses, opticians have espoused their apparent benefits for years.

It was claimed that by blocking out blue light, the highest energy part of the visible light spectrum, the glasses could take some strain off the eye, help with sleep and protect the retina.

Modern screens, such as smartphones or computers, emit more blue light than traditional, more mellow sources and it was suggested that wearing blue light lenses while using technology might help.

Blue light lenses can be added to a prescription for around £30 at all major glasses retailers and people are also wearing blue light lenses at work without a prescription in the hope it saves their eyes from screen glare.

“Over the past few years, there has been substantial debate about whether blue-light filtering spectacle lenses have merit in ophthalmic practice,” said Prof Downie.

“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.”

Experts are calling for larger, more substantial studies to be run in order to give a better guide as to the efficacy of the glasses.

But Dr Sumeer Singh, a postdoctoral research fellow at University of Melbourne, said the proportion of blue light to which a person actually is exposed is minimal.

“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,” she said.

“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.”

The review was called “gold standard” by Prof Andrew Przybylski, director of research at the University of Oxford’s Internet Institute, who said the notion that blue light from devices negatively impacts health and sleep “is popular but not well evidenced”.

He added that the standard of the 17 studies was of such a low standard that less than half had basic statistics provided, which means the negative result of the review could be a consequence of “garbage in, garbage out”.

“This review is fairly damning. 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.

“It would be a good thing that people apply the same wariness they have towards technology to the research that confirms their fears and to those who sell quick-fix solutions.”

The report is published in Cochrane Database of Systematic Reviews.