I found the basic premise of this blog post to be incredibly flawed. The author seems very sure of himself that blue light filters don't work, but making arguments related to cell types and emissions spectra and circadian rhythms is not the way to make a conclusive argument in a topic like this. Science is littered with recommendations about things that "plausibly" made sense, but that turned out to be flawed or just absolutely wrong when actually put to a real, scientific test. One example most people are familiar with: the recommendation against eating eggs in the 90s was based on the fact that eggs have a lot of cholesterol, and we knew high LDL levels in blood were associated with a greater risk of vascular and heart problems. So, "logically", it seemed that limiting dietary cholesterol would reduce heart disease. Except when scientists actually tested those recommendations, they turned out to be largely wrong - when you eat a lot of cholesterol, for most people their body's natural production of cholesterol goes down, so unless you're in the small subset of people who are particularly sensitive to dietary cholesterol, eating eggs is fine.
Making recommendations based solely on a theoretical mechanism of action is bad science. The only way to actually test this is with a study that looks at different types of light restriction and its effect on sleep. Obviously it's kind of impossible to do a blinded study for blue light filters, but you could get close by testing various permutations of light changes (e.g. total luminescence, eliminating only very specific wavelengths, etc.)
As another commenter said, it may be a placebo effect, but if it is, who cares? All I care about is that I get a better night sleep, and as someone (unusual among programmers I know) who really doesn't like dark mode, a screen reddener greatly helps me at bedtime.
His argument seems to be that the night modes don't remove much blue. My initial assumption was that it was about physical filters. Yellow or amber 99%+ safety lenses are a thing and several of my coworkers wear them. Looking through them at those painfully bright blue leds makes them appear to be off. Yes everything looks strange, but they work. Likewise a different coworker manually removes all blue in the monitor settings themselves independent of the brightness setting. That also works. The author's assertion should be qualified amd narrowed a bit.
I can absolutely confirm that night mode works wonders. Since ten years ago I discovered them I no longer have dry eye like problems.
This is great it works for you but hopefully you realize the weakness of anecdotal evidence when it comes to declaring something is universally effective.
Your n of 1 argument is the equivalent of âmy grandpa smoked until he was 95 so smoking clearly canât be bad for your healthâ.
Blue light blockers are a scam that was created when some circadian rhythm research went viral (in a highly misrepresented way) online a few years ago. It's a stunt to make some quick cash from unwitting buyers.
"It's a stunt to make some quick cash from unwitting buyers."
I've used a number of blue light filters, and I've never paid for them.
My Gunnars give me immediate eye relief after a day of work looking at a display. Are you sure it's a scam?
To the extent that there's some sort of clinical statistically significant lift over, say, however you might control for a placebo here, who knows? To the extent that it's working for you in a meaningful way, placebo or not... does it even matter? If they're working for you, they're tautologically not a scam, except insofar as you find yourself missing out on benefits promised that aren't being realized, or you feel that the price you've paid is disproportionate to the benefit because some much cheaper option exists in some sense.
Put another way, placebo or not, if there's an effect, and it's a positive one for you, it really doesn't matter. It's working.
But you could make your same argument for the pro blue light filter side.
Sure, and I'd write the same thing if we were talking about a blog post that said everyone should use blue light filters because of some plausible physical mechanism.
Did you read the article? He points out âItâs possible that Night Shift does something, but the biggest study I could find of Night Shift mode (still a pretty small study) found little effect on sleep, so if thereâs an effect, it must be tiny.â He links the exact type of observational study you asked for
Regardless the maximum possible effect will be constrained by the biology of the cells responsible for responding to blue light. Maybe knowledge of the biology is incomplete or flawed but to not use it to inform whatâs possible seems foolish.
So what if itâs a placebo effect? Well some people are spending money and time investing in blue light filtering glasses and other solutions. Itâs potentially snake oil and it could keep them from pursuing better solutions that would actually help them sleep
If the author goes "I couldn't find enough high quality studies on the topic I'm discussing", then the conclusion should be that we need more studies, not to come to unwarranted conclusions in the absence of actual data.
> Well some people are spending money and time investing in blue light filtering glasses and other solutions.
Ironically, we actually do have a number of good studies on the effects of blue light filtering glasses (easily findable with a Google search) and they do demonstrably reduce onset of sleep time. Where more research is needed is on software-only filters for screens.
If that's the case, I want to see studies on how blue light filtering glasses fare versus just regular-ass sunglasses (of equivalent tint). Is it the reduction of blue light that helps people, or is it just the reduction of light, full stop?
Just the latter on its own is quite thoroughly proven to help people sleep, and helps with migraines, and so on.
Or what about UV light? I've never seen anyone say that an anti-UV coating/lens material in glasses helps with sleep (nor that it doesn't). But UV is still high frequency light that enters our eyes, even higher frequency than blue light, and there's at least some research to suggest it might affect human circadian rhythms despite its invisibility to us. But I've never seen anyone suggest that wearing your regular glasses (because most regular glasses these days are UV-blocking) before bed, or before a nap during the day (or before trying to sleep through the day, for a night shift worker), could help someone get to sleep.
I'd imagine it could also depend on exactly how much blue light is filtered; it's not like all blue light filtering glasses are tinted to the same degree. Glasses that all but make the world look like a reptile house might do a lot more than glasses that have only the faintest of orange tints. It's not like lenses either block blue light fully or don't block it at all; there's a spectrum here. How much blue light is supposed to get blocked for it to matter?
Were the studies that showed blue light blocking glasses to improve sleep done with lenses so tinted they were essentially sunglasses, or did they use nearly clear/only slightly tinted lenses akin to the blue light blocking lenses that are marketed as alternatives to regular clear lenses?
That sentence does not give me a lot of confidence. The conclusion does not follow the initial statement at all.
They absolutely help my eyes not be so strained. If its placebo, its a working placebo.
>Are people actually using Night Shift? >Aggravatingly, yes.
What is the authors problem lol? It feels a lot better on eyeballs to use warm light things. Why does he care?
I find it somewhat pleasant, but by far the best thing I did to help my eye strain was greatly lower the brightness. Basically, I was told to make it so that my phone's camera could see something on the screen and my desk at the same time without washing out.
After doing that, I have found that the "temperature" of the screen doesn't really matter to me that heavily.
> Basically, I was told to make it so that my phone's camera could see something on the screen and my desk at the same time without washing out
+1. The low-tech version of this I've heard and I've been doing is:
Hold a printed white paper sheet right next to your monitor, and adjust the amount of brightness in monitor so the monitor matches that sheet.
This of course requires good overall room lightning where the printed paper would be pleasant to read in first place, whether it's daytime or evening/night
I think this was what I was told the first time. The advantage of taking a picture with my phone's camera is it kind of made it obvious just how much brighter the screen was then the paper.
Which, fair that it may be obvious to others to just scan their eyes from screen to paper. I've been surprised with how much people will just accept the time their eyes have to adjust to a super bright screen. Almost like it doesn't register with them.
There's some overlap with bias lighting here - good overall room lighting works if you've got good daylight, but it's much easier to get bright bias lighting at night than to light up the entire room.
Concur that most displays are set 25-50% too bright by default.
I confirm that this helps me as well. Quite often I don't have any fancy filter, I'm permanently setting display/monitor to low temperature and my eyes/vision couldn't be happier. I don't even need darkmode, regular mode works just fine for me as long as blue light is toned down. Granted, I'm not doing any color correction or anything color sensitive work.
I used to have terrible headaches about 20 years ago when I started spending a lot of time in front of the screen. I went to an optometrist who tested my eyes and told me I could get low prescriptions (.5) but warned me that there's no way back and that many people are fine with my current vision, choosing not to get a prescription. Luckily I figured out that it was blue light that was bothering me and once I turned it down I haven't had any problems since. I'm in my mid 40s and my vision has naturally deteriorated a bit but I am still fine with no prescriptions.
And I don't believe this to be placebo. Every time I stare at a regular screen for longer than 5 minutes I get eye strain. At the same time I suspect this doesn't help everyone, but at least to me this is a great solution that still works.
Can you elaborate on âno way backâ?
Not OP, but when I got glasses as an adult and while they really improved the sharpness of my vision I could feel my unassisted vision getting worse, so I stopped using them and get by with slightly unfocused but unassisted vision. I assume if I wore them full time my unassisted vision would degrade to the point where I then need the glasses full time.
I meant that once you decide to wear prescription optics you canât go back to not wearing them, of course excluding eye surgery. In my case I could stick to good enough vision and luckily 20 years later Im still not wearing glasses. My main point was that I was getting eye strain from blue light and once I reduced it the problem dissapeared.
Is the author arguing anything about eye strain? The word âstrainâ doesnât even appear on the page.
I think theyâre purely talking about the idea that cutting back on blue light will help you sleep better. Nothing else.
Why would the author care? Honestly it does seem like one of those junk science things that popped up a couple years ago that all of a sudden was everywhere. I literally remember comments here on hacker news from people saying Apple was killing people because they were blocking F.lux and didnât have night shift yet. Yes they were the most hyperbolic, but they were there.
I kind of like Night Shift too, for similar reasons. But I donât think it ever did anything for my sleep. Nor did I ever expect it to.
> What is the authors problem lol?
I'm not the author, but every time I've seen Night Shift (and things like it) being used, they've done a grand job of royally fucking up the colors of whatever's on screen.
> It feels a lot better on eyeballs to use warm light things.
That's, like, your opinion, man. The lights in my house are all 5000K lights, and I love it.
I expect you'd get way more out of reducing the brightness of your screen [0] than fucking with its colors. So many people seem to love having searingly-bright screens shining into their faces... I don't get the fascination.
[0] If you've got the monitor's brightness at minimum and it's still too bright, then there are software controls to further reduce it.
I respect that other people have the right to their opinion, but 5000K lights 24/7 is so completely insane to me. How? How do you get by with "dentist office mall kiosk" lighting blaring every hour of the day?
I have an adaptive Lifx bulb that changes from 5000K during the day and then shifts down to 3000K at night, before tapering down to 2700K for overnight and it's amazing. 5000K in the corner of a dark room is just so disjointed and intense and upsetting to me, if I stay at an Airbnb for more than a night or two and there are daylight bulbs installed, I'll literally buy replacement bulbs and change them out.
> they've done a grand job of royally fucking up the colors of whatever's on screen.
Pretty sure that's the point?
You can just do things. Not everything needs a study, you donât have to justify yourself to anyone!
Try things, if you like them, do them!
Try not living a neurotic âstudyâ based life, I am trying it and its pretty great!
You can and should! Just donât go justifying that your choices are rooted in science when they arenât.
What, you think Newton relied on a study to believe his own conclusions?
You think Newton couldn't devise a reasonably quantitative experiment?
I am aware that meta-studies of glucosamine chondroitin show No Significant Gains in joint pain. I would never waste my money on it.
But my newly adopted dog had hip issues, and I bought a few months worth of a diet supplement in the hopes of doing something meaningf... dammit, it's glucosamine.
They claimed double-blind studies showed decreases in limping in just two months.
Two months, more or less, I stopped seeing him limp by the time we left the dog park. He still does sometimes, but it's rare - not every damn day, by any means.
We aren't that fricking different biologically from dogs in our skeletal attachment system. Maybe it's still a placebo, but it seems to defeat that idea. Maybe enough human issues are based on things that don't translate to dogs - sitting at a desk all day, eating junk food, walking upright... - that it helps them, but not enough of us.
Don't know. These GC supplements have convinced me it's worth my money, and he loves eating them, so he votes 'yes', too.
I found it interesting that placebo effect is also sort of relevant in pet care: it makes owners believe the pet is doing better.
Unfortunately, the study that showed this used the same medicine my dog had been on, and since it was for epilepsy, I can totally believe that whether I thought it worked had no connection to its effectiveness.
Yes, I'm aware I'm not a double-blinded observer. Hard to find those in personal spaces.
Absolutely and this is something that can be tested rather easily. If blue filters aren't immediately helpful to eye strain then they probably don't work for you but if they are they probably do work for you.
Every dismissive reply talks about eye strain nada that is by far not what the author is taking about.
You can test the negative easily, but the positive is harder. Thus: placebos.
On the level of the individual a working placebo is a success.
You're saying that my eyes straining going away from reduced blue light is placebo? I can feel it right away and it gets worse in minutes, time and time again. As soon as I remove blue light the strain is gone. Honestly, I don't care what other people have to say, to me it's obvious that it helps and I stick to it. Again, I don't think this is universal and it may not help you if you don't notice immediate improvement.
Neurotic is bad by definition, but using studies to inform your habits seems like a wise thing to do.
Obviously you shouldn't follow studies blindly, especially because many studies are poorly conducted and do not replicate, but in general, we know that just following your gut is suboptimal and sometimes dangerous in cases when studies give us clear information.
Unfortunately it doesn't seem to be easy to understand what studies are actually demonstrating, based on how often you see people making giant leaps to conclusions that don't really follow from study results.
> Unless your strategy is to create a photo-lab-like screen in pure black and red, or wear deep-red-tinted glasses, itâs unlikely that a pure colorshift strategy will cut out that big of a chunk of the spectrum.
I absolutely think this is the right approach. The glasses which do 'blue light filtering' which barely change your perception are clearly placebo, but a very strong redshift I think is obviously a different creature.
I have a red flashlight I use at night to read books. Itâs weird after an hour I donât really see it as red anymore, just dim off white.
Absolutely, although dark orange seems to work well enough. If you can put them on and still tell the difference between most colors, they aren't working. I use my pair for one purpose: reading in bed with a backlit e-reader. I can't imagine trying to do much else with them on, they have plastic wings to block light from the side and they're not light.
But they work.
Night shift seems to have a very strong causal effect on my sleep cycles. Up until about ten years ago I was a night owl, rarely falling asleep before midnight and rarely waking up before 8. Then I started getting serious about light hygiene and using night shift and now I'm a serious day person, rarely staying awake after 11 and rarely waking up after 7. But the real clincher is that when I travel I don't change the time zone on my computer (because it screws up my calendar). But my sleep cycle continues to track my home time zone for a very long time. I life in California, but at the moment I'm in Hawaii. I've been here three weeks so far. At home I'd fall asleep around 11 and wake up around 7, but here I'm getting sleepy at 9 and waking up at 5.
My wife, on the other hand, is a hard-core night owl even with night shift. So apparently there is a lot of individual variation.
This article has inspired me to do a control experiment by switching night shift off. Check back here in a week or so for the results.
> Night shift seems to have a very strong causal effect on my sleep cycles.
> light hygiene and using night shift
The OP article is primarily about separating the variables you lumped together.
I remember when I found Flux (third party predecessor to night shift) sometime in 2013. It worked in a week, I'd been staying up until 3am for most of the year and a started going to bed at midnight.
> light hygiene
Awesome, hadnât come across this term before.
You might appreciate the concept of chronotypes.
https://en.wikipedia.org/wiki/Chronotype
The DOAC podcast recently hosted Dr. Michael Breus on same.
Apple Podcast link, or conjure your own:
https://podcasts.apple.com/au/podcast/the-diary-of-a-ceo-wit...
Bear in mind that chronotypes, as stated in the wiki, only varies about 2-3 hours from each other. This is just to say that there is no nocturnal person in terms of biology, we are all diurnal mammals after all.
Yeah, like anything, proponents like the guy in the podcast I referenced probably overhype the importance / impact.
Yep, when you expose night owls to just natural light they go to sleep earlier like early birds.
Been more careful with my lighting this week :) howâs yours?
>It doesnât make any sense in 2026 that Gmail doesnât have a dark mode
I've been using dark mode on gmail for years, not sure what OP is talking about here.
But also, my sleep quality got much better when I turned on f.lux. And it got better still when I added a second light to my bathroom that can do a 1800K super-warm light (that's also very dim).
And as an added pro-tip, I use f.lux during the day to cut my color temp to 5900K (instead of the default 6500K) and it made a huge difference for how long I could work without getting tired eyes.
I have my phone in monochrome (i.e. greyscale) mode and just subjectively it's much easier to look at especially at night. I have it at the lowest brightness and it's still very readable. Human eyesight is basically monochrome in low light settings anyway.
I have an accessibility shortcut to turn my screen greyscale with triple taps but I kept turning it off so I could see the clues on sudoku and now I've forgotten I even had this for almost a year
Low brightness is great though. I didn't realize most of the battery drain on a phone is often just the screen. Lowering the brightness to as little as I need has been great for battery life
I bought some amber glasses from blublocker.com[1], because they link to a research paper that actually measured how much of each wavelength their filters allow (as well as other brands). They're pretty dark, so you have to crank up the brightness on your screen, but I'm confident that I'm not getting ANY blue.
1: https://www.blublocker.com/blogs/news/what-blue-light-blocki...
Those glasses state that they are the only pair that âblocked 100% of harmful blue light in the 400-450 rangeâ
But melanopsin contained in the cells that regulate circadian rhythms have an absorption spectrum extends to slightly beyond 540 nm (see the OPâs post). As the author says, âItâs not sensitive to blue, itâs sensitive to cyan (and blue and green).â
Those glasses probably do what they say in terms of wavelengths they filter, but they are only partially filtering out light relevant for circadian rhythm regulation and sleep.
Nice. The article also mentions BluTech lenses (BluTech LLC, Alpharetta, GA). I've found the marginal utility of bluelight blocking solutions are very context specific, indeed. And mostly-completely bahokie garbage, sadly, but not when it's BluTech and BluBlocker. BluTech/BluBlocker for the screen-induced fatigue is the correct solution. I always get BluTech HI Indoor AR pucks for my prescription lenses. And just switch to prescription sunglasses when I go outside.
Get a daily email with the the top stories from Hacker News. No spam, unsubscribe at any time.