Are Blue Light Glasses A Complete Waste Of Time?

A new study casts doubt on the trend of avoiding blue light

Pictured: Stock photo of a guy wearing glasses. Almost certainly not even blue light glasses. At least it’s a good photo. Photo by Fábio Lucas on Unsplash

Blue light is one of the many things that hits the headlines often, because it is both a symptom of the modernity and also a thing that is vaguely theorized to be potentially bad for you. We all love to hate something we invented only decades ago.

One of the newest healthcare fads is blocking blue light - yes, literally just light that is blue - and one of the faddiest ways to do this is using glasses. But recent headlines popping up around the globe have argued that actually these glasses are totally ineffective.

So let’s take a look at the data, and see whether there is much reason to stick odd-looking glasses on your face to protect from certain parts of the electromagnetic spectrum.

The Science

The idea that blue light is bad comes largely from the fact that it isn’t natural. In the natural world, the only blue light you get is from the sun, which puts out the entire gamut of colours. So if you see blue at a time when humans wouldn’t naturally get any in their eyeballs - say, at night, when the sun isn’t around - it’s unnatural and therefore problematic. There’s also a theory that blue light causes additional strain on your eyes, because you wouldn’t naturally get a lot of it if you were living cheerfully in the Paleolithic era.

Hilariously, what comes up when you search Paleolithic on stock photo websites is a whole host of things that simply DID NOT EXIST at that time. Charcuterie is a particularly funny example. Photo by Kim Daniels on Unsplash

This has led to a slew of products aimed at preventing you from getting blue light into the brain. They range from expensive phone screen overlays to simple settings changes on your devices that can stop them from emitting certain parts of the electromagnetic spectrum. But blue light can come from many things - such as your normal household lighting, and so one fad is to wear blue light blocking glasses.

The new study that’s making headlines is a review by the Cochrane Collaboration. I’ve talked about Cochrane before, but they are basically the gold-standard for the appraisal of evidence in medical interventions. If you want to know if something works, you go to the Cochrane Database of Systematic Reviews and hope that they’ve looked into the question.

The group at Cochrane looked into the question of whether blue light blocking glasses had any benefits for human health, including sleep, eye strain, and other issues. After looking through hundreds of studies in the scientific literature, they identified 17 studies assessing blue light glasses. None of those studies found a convincing benefit for the glasses on any metric examined.

Pictured: Fine, apparently. Photo by Alexander Jawfox on Unsplash

Thing is, this finding was more about a lack of evidence than anything. Of the 17 randomized trials that have been conducted looking into blue light glasses, only two had more than 100 people enrolled, and only one of those was half-decent. What the review really shows is that most of the evidence so far looking at blue light glasses tells us little to nothing about whether they work.

We do have that one half-decent study. In 120 people randomized to either have blue light glasses or not, there was no benefit to wearing them on a range of measures related to eye strain while doing tasks on a computer. So for at least that claim, we have pretty good evidence that these glasses are unlikely to have a benefit.

But for the much more interesting question of whether these glasses help with sleep, or long-term eye disease, there just wasn’t much evidence. Many of the trials included fewer than 20 people, which is not useful for determining whether an intervention is likely to work.

To quote the authors of the review:

Potential effects on sleep quality were also indeterminate, with included trials reporting mixed outcomes among heterogeneous study populations. There was no evidence from RCT publications relating to the outcomes of contrast sensitivity, colour discrimination, discomfort glare, macular health, serum melatonin levels, or overall patient visual satisfaction. Future high‐quality randomised trials are required to define more clearly the effects of blue‐light filtering lenses on visual performance, macular health and sleep, in adult populations.

This is scientist-speak for “we couldn’t find any good evidence, and the bad evidence was contradictory”.

Bottom Line

Most of the headlines I’ve seen about blue light glasses are wrong, because they are far too definitive about this very uncertain finding. What we can say from this review is that these glasses are unlikely to help with eye strain when working using a screen. That does have some implications for their ability to help with eye strain generally, but it’s not definitive for other outcomes. As for sleep and health more broadly, the research is insufficient to draw any firm conclusions.

That doesn’t mean you should go out and buy these glasses, of course. The idea that extra blue light is impacting your sleep is itself not well-demonstrated, and the solid belief that glasses will ameliorate the issue helps no one but glasses salespeople. Personally, I’m not worried about blue light as a health issue - the evidence I’ve seen has been very unconvincing - but on the other hand you can get very cheap blue light blocking specs so if you really want to use them I have no strong opinions.

The only advice I’d give is that they all look silly, so pick a cheap pair.