I was trading New Year’s resolutions with a circle of friends a few weeks ago, and someone mentioned a big one: sleeping better. I’m a visual neuroscientist by training, so whenever the topic pops up it inevitably leads to talking about the dreaded blue light from monitors, blue light filters, and whether they do anything. My short answer is no, blue light filters don’t work, but there are many more useful things that someone can do to control their light intake to improve their sleep—and minimize jet lag when they’re traveling.
My longer answer is usually a half-hour rant about why they don’t work, covering everything from a tiny nucleus of cells above the optic chiasm, to people living in caves without direct access to sunlight, to neuropeptides, the different cones, how monitors work, gamma curves, what I learned running ismy.blue, corn bulbs, melatonin, finally sharing my Apple Watch & WHOOP stats. What follows is slightly more than you needed to know about blue light filters and more effective ways to control your circadian rhythm. Spoiler: the real lever is total luminance, not color.
↫ Patrick Mineault
And yet, despite a complete and utter lack of evidence blue-light filters do anything at all, even the largest technology companies in the world peddle them without so much as blinking an eye. It’s pure quackery, and as always, we let them get away with it.
The largest optician chain in the UK, Specsavers, offers a blue light filter coating on their lenses but the only mention of this is on their page debunking blue light filters.
I use the accessibility features to make my screen all red tinted. This does not affect the daylight receptors in the eyes and is also respectful of astronomy enthusiasts if you ever visit their gatherings.
Companies added these in response to users clamouring for this*. Sometimes users want irrational things, is it the responsibility of providers to deny them that?
* I should know, silly as it is, I ran third party tools for years to get this functionality.
I think the long-standing knowledge that exposure to blue light destroys night vision, a hard reality of astronomy and photography for many years which seems unquestionable. Unless of course astronomers and photographers have been in on the “blue light conspiracy” for over 100 years now! I suspect it’s very unlikely the effect of blue light is 100% conspiracy and zero physical manifestation. For me the biggest problem will be trusting people to self-report reliably, and most of the studies rely on a degree of self-reporting. What is really needed is an objective measure of a physical effect, instead of subjective self-reporting, and think that is still some way off.
cpcf,
Self reporting could be problematic. Surely there’s got to be a scientific study that doesn’t rely on self-reporting.
This link suggests red light is used because it’s easier to stay acclimated to the dark.
https://www.giangrandi.org/optics/eye/eye.shtml
This seems plausible to me, but it doesn’t necessarily imply anything about sleep quality. I’m wondering if there could be a physiological link, those who deliberately practice nighttime routines may put themselves in a mental state for better sleep. Many parents find nighttime routines helps with putting kids to sleep. Setting lights to red could become part of one’s routine but it might not have the same impact on someone else. The blue light bad theory seems to get contradicted when students get sleepy in class under some of the harshest lighting conditions they’re likely to encounter. The quality of sleep is probably more correlated to brain activity than the color of light before sleep.
Alfman
I think when a physical effect is demonstrated, like night vision, then it’s unlikely there won’t be some related impact. Years ago when I was studying astronomy and astrophysics, I recall reading a paper that had something to say about hypersensitivity to red light, a topic of interest to astronomy back in the pre-digital days. If these people exist, and I have no reason to doubt they do as it’s a medically documented condition, then it’s likely the same exists for other wavelengths as well. There was also a paper that looked at the natural daylight spectrum, and how our vision has evolved in the presence of the Sun, it makes sense. It leads to bigger questions, like why flowers and insects use UV wavelengths.
It would be a tad hypocritical to report the existence of these phenomena then claim in a round about way that we humans are immune!
From my perspective, much of this blue light discussion seems based in gross generalisations, ignorance of nature and half truths on all sides of the debate.
cpcf,
I personally don’t notice colors making a difference for me, but I agree with you that we should not generalize because it could effect people differently. Sometimes even placebo pills are shown to work, there might be a placebo effect here too. I don’t know either way, but it highlights the trouble of relying too much on anecdotal evidence.
Given that sleep studies are a thing, I would think someone’s run the experiments and collected the data in a more scientifically rigorous setting. I’d be curious to read what the scientific data says across a larger dataset.
I’ll go with the evidence-based communities using blue light/red tint filters extensively at night like astronomy, aviation, submarines, etc.
Blue light filters have provided a clear improvement in my quality of life, for very little changes in terms of the graphics pipeline, when I have to work at my monitor late at night. So I have no idea what the point of that post really is.
Xanady
I think it’s common sense that some people will experience effects to varying degrees, the mistake is to generalise, marketing companies generalise and project because it’s profitable. We all have an ailment they can cure, or we have every ailment, we can push back and call that claim generally bogus, but the reality is some people do!
Totally, and that’s where it gets slippery because “common sense” is basically just pattern recognition with a confidence boost. People react differently, always have, always will, and the moment you try to flatten that into a single neat claim you’re basically doing PR, not reality. Marketing has to generalise because it can’t sell nuance, it sells a story that fits on a label, and the easiest story is “this is you, this is your problem, this is your fix.”
And yeah, you can call the broad claims bogus because a lot of them are, but it’s also not nothing just because it’s overhyped. Some people do get real effects, sometimes strongly, sometimes subtly, and that’s the annoying bit: the existence of genuine cases gives the whole thing a glow of plausibility, which then gets projected onto everyone else. So it turns into this weird loop where the generalisation is wrong, but not uniformly wrong, and that’s exactly the gap companies wedge themselves into.