You know, it's funny - there's a couple places where this kind of thing seems to have come up. There's research around crop nutrition levels that shows decreases in nutrient levels as yield per acre goes up, there's research on supplements and vitamins that shows synergistic effects between seemingly unrelated substances, we've seen surprising effects from adding or removing species from an ecosystem. One begins to suspect that the "reductive" method of science - the sort of physics- or mathematics-type "reduce the variables of the problem until we can isolate effects" approach - isn't particularly well-suited to dealing with biological systems. You see it in bioinformatics as well - we've sequenced the genomes for many organisms, and have learned a lot from doing so, but we're also learning the limits of that approach pretty strongly - the organism isn't defined just by its 'code', but its environment; the presence, distribution, and concentration of various chemicals; etc. I suspect as we move more towards the "biological" century here we're going to have to readjust how we approach things to start trying to find those synergistic effects earlier in the process, rather than pull everything down to its constituent parts and then experimenting pairwise with various combos. I get the difficulties in doing that, but I feel like we've repeatedly found the stuff we've discarded as irrelevant to the problem ("things that are not in the visual wavelength the eye perceives") in fact do wind up being relevant (wider full-spectrum light has effects outside the mere spatial perception of objects).
I have a theory that cheap LED lights with low quality drivers are bad for dogs. LEDs with low quality drivers very often have a high amplitude flicker at 50/60Hz, which is about the flicker fusion rate for humans so we don't perceive it (at least usually), but dogs are known to have a substantially higher flicker fusion rate and probably perceive the flicker. Probably worth considering, especially if you have a dog with epilepsy.
(Incandescents also flicker at 50/60Hz of course, but the thermal inertia of the filament makes this a lower amplitude flicker.)
The push toward LED seems to be primarily for emission target related reasons. It is very hard to buy incandescent bulbs in the UK; even for those of us that accept the cost implications. Also, many less expensive LEDs flicker at the rate of the frequency supply of the current (ie 240 or 120 Hz). This is very annoying and related to the instantaneous response of LED vs the averaging effect of the alternating current through an actual glowing hot filament. It is interesting to read on the development of blue and white LED technology.
There is a 15-30% difference between the groups at baseline (fig 8c-9c, 8d-9d), about the same magnitude as the claimed effect of the experimental condition.
I think the result would be much stronger if these baselines were comparable, so they show they have accounted for other variables like time of day and light history. I am also skeptical of any effect in the retina lasting 6 weeks, with no fading.
Consider that people are often exposed to much more infrared light outdoors, so "worked under a relatively dim incandescent lamp" is not a particularly novel stimulus. Imagine that any of these people spent time outdoors during the six weeks - thousands of times more infrared light there.
I’ve always been mildly bothered by the LED lighting in my home, as if it’s simultaneously bright but not illuminating. In simple consumer terms, if I wanted to shop for a variant that more closely replicated incandescent lighting, what exactly am I looking for on the packaging? Or does this not exist?
Very interesting. I've always thought that there was something a bit "off" about LED torches and car headlamps; the brightness is there, but something about the light just doesn't seem to illuminate as well as an old dim incandescent or even fluorescent tube.
Just to point to anybody that comes here directly, the article has no relation at all with perceived illumination, color fidelity, or anything else people complain about leds.
It's an interesting niche topic that you may want your working place to notice if you work indoors.
It was known among MTB riders who ride at night sometimes: typical XM-L T6 Chinese headlights were unusable in the forest when you move fast. Good diodes (like Nichia 219B) worked. And XM-L was dominant even in very expensive «brandnamed» lights for many years (you could buy Aliexpress headlight for $20, you could bu "Italian" lamp for $250, result is the same)
I'm not in this scene anymore for many years, but when I was, I built my one lamp from custom light engine (essentially round PCB with DC-DC current limiting schematics an LEDs) with 3x219B, Chinese body and CARCLO TIR Optics...
Was just discussing last week with a colleague how for the same 'lumen' there was such a dramatic difference between led and incandescent bulbs for ease of reading paper books.
wouldn't this be a good thing? I prefer my circadian cycles not to be disturbed by artificial lights and if i am reading this right, it is what happens with led lights. this would be different of course if i had no access to natural lights. glad to be corrected :)
It should be noted that even if we assume that the conclusion of this study is correct, i.e. that artificial lighting should have a wide spectrum including near-infrared light, that does not mean that returning to classic incandescent lamps is the right solution for this problem.
The incandescent lamps with tungsten filaments have a much lower temperature than the Sun, thus much more energy is radiated in infrared than needed.
There was about a year or two ago a discussion about a very interesting research paper that reported results from testing an improved kind of incandescent lamp, with energy efficiency and lifetime comparable to the LED lamps.
The high energy efficiency was achieved by enclosing the lamp in a reflecting surface, which prevented energy loss by radiation, except for a window that let light out, which was frequency-selective, so only visible light got out, while infrared stayed inside. The lamp used a carbon filament in an environment that prevented the evaporation of the filament.
With such a lamp, one can make a tradeoff between energy efficiency and the content of healthy near infrared light, by a judicious choice of the frequency cutoff for the window through which light exits the lamp.
Even with enough near-infrared light, the efficiency should be a few times higher than for classic incandescent lamps, though not as good as for LED lamps. Presumably, one could reach an efficiency similar to that of the compact fluorescent lamps (which was about half of that of LED lamps), for such an incandescent lamp that also provides near-infrared light.
I find it a little strange that there is no real discussion of limitations in this paper. They mention the limitations of something they cite, but nothing about the data they themselves collected or the conclusions they draw from it
I've been using incandescent more often. All my vanity lights are 40w appliance bulbs now. The difference at night is remarkable. The LED is just too much even at 2700k. I still prefer LED for high power situations like br30/40 can lights.
Scientific Reports is a junk journal fyi. Not conclusive, but indicative.
Despite saying the visible flux component is "small" and that the tungsten lamps "were not expected to [be used] as task lamps," Figure 6 (a) and (c) shows... desk lamps right at the work stations like task lamps! Not only is this experimentally unblinded, but the visible light immediately in front of the test subjects is noticeably brighter and warmer. The effect could simply be due to reduced eye strain.
What would James Randi do? "Extraordinary claims require extraordinary proof," and unfortunately this isn't it.
This would be more interesting if they add a visible light filter on the lamps so they only emit infrared radiation, and have an identical double-blind control with a 60 watt heater bulb so it emits no SWIR but the same radiant heat (which could confound and/or unblind).
No mention of CRI which seems kind of odd. LEDs for lighting are increasingly graded by how natural their emission spectrum is. Older lights are quite bad, newer ones sacrifice a tiny bit of performance for more uniform spectrum.
This should also be true for TL lights. Which kinda contradicts common sense seeing that those are used all over the place in offices, kitchens, and hospitals, makes me think this paper is bogus.
Yes, there is something obviously wrong with most LED lights, but it isn't too much of short wavelength light, but on the contrary. It's the near absence of cyan light in most LEDs. Our eyes are by far the most sensitive to it, the majority of receptors in the eye are sensitive to it, and we may focus primarily on it (focus differs for different wavelengths). This is how you get the feeling of something being wrong with your vision as you for example walk into a mall, and so on.
If anything, higher temperature lights seem to make it better, not worse, but the problem will persist as long as the cyan hole stays there.
The authors, bless their hearts, suggest that running halogen lamps at lower-than-rated voltages might be a good idea.
> If this is done with a halogen bulb, which is a type of incandescent tungsten bulb, the filament lasts for a longer period as evaporated tungsten is redeposited on the filament rather than blackening the bulb glass. Hence, using a halogen bulb at lower voltage is a realistic alternative in terms of health and energy consumption.
Unfortunately, as I understand it, the redepositing action only occurs at high temperatures.. It's a chemistry thing. I have been led to believe that running halogens at low voltages will cause the bulb glass to blacken sooner. See https://en.wikipedia.org/wiki/Halogen_lamp#Effect_of_voltage...
I hate the LED street lamps so much. I can tell they've got a really spiky and unnatural spectrum, unlike the HPS lights, not to mention that they're white or bright yellow...
There are some full spectrum led lights, they just cost over $100 a piece. And they might get banned in the future for not being energy efficient enough.
I found some interesting tidbit about this bigger issue. And I want to share how to more easily check it.
We many times see some people reporting that they clearly see lower quality LED light flicker and is really distracting to them and even causes them headaches.
Now, I didn't see this until recently (unless in failing lights) in the right conditions. If the light is very, very dim: For instance, only 1 light on in the night, and you are in a division far away from the light so that it's extremely dim. There, I could finally really see it flicker.
I've replaced that light for a better one and the effect went away.
I have incandescent light bulbs at home I have to pretty much smuggle from China. It's amazing how we're replaying the asbestos playbook a century later. Only this time it's government mandated.
Why is it that right now there is still on the frontpage of an "article being found flawed after 6k citations " ( https://statmodeling.stat.columbia.edu/2026/01/22/aking/ ) but this random article coming out of nowhere makes the front page on the same day?
People really should get it and stop sharing newly published papers to the general public. The value of one single academic paper is exactly 0. Even a handful of such articles still has 0 value to the general public. This is only of interest to other academics (or labs, countries, etc.) who may have the power to reproduce it in a controlled environment.
Be very skeptical of correlations like this that have dubious or poorly understood causation. Be even more skeptical if they are about day-to-day stuff that would likely have large swaths of people able to reproduce something like it on huge scales yet they haven't. Extraordinary claims require extraordinary evidence.
LED lighting undermines visual performance unless supplemented by wider spectra
(nature.com)207 points by bookofjoe 25 January 2026 | 195 comments
Comments
(Incandescents also flicker at 50/60Hz of course, but the thermal inertia of the filament makes this a lower amplitude flicker.)
I think the result would be much stronger if these baselines were comparable, so they show they have accounted for other variables like time of day and light history. I am also skeptical of any effect in the retina lasting 6 weeks, with no fading.
Consider that people are often exposed to much more infrared light outdoors, so "worked under a relatively dim incandescent lamp" is not a particularly novel stimulus. Imagine that any of these people spent time outdoors during the six weeks - thousands of times more infrared light there.
It's an interesting niche topic that you may want your working place to notice if you work indoors.
I'm not in this scene anymore for many years, but when I was, I built my one lamp from custom light engine (essentially round PCB with DC-DC current limiting schematics an LEDs) with 3x219B, Chinese body and CARCLO TIR Optics...
Good times.
That seems remarkable and almost too good to be true?
https://www.hubermanlab.com/episode/red-light-to-improve-met...
The show notes have links to quite a few more papers. I have no idea if this is good science but this is not just a one off paper.
The incandescent lamps with tungsten filaments have a much lower temperature than the Sun, thus much more energy is radiated in infrared than needed.
There was about a year or two ago a discussion about a very interesting research paper that reported results from testing an improved kind of incandescent lamp, with energy efficiency and lifetime comparable to the LED lamps.
The high energy efficiency was achieved by enclosing the lamp in a reflecting surface, which prevented energy loss by radiation, except for a window that let light out, which was frequency-selective, so only visible light got out, while infrared stayed inside. The lamp used a carbon filament in an environment that prevented the evaporation of the filament.
With such a lamp, one can make a tradeoff between energy efficiency and the content of healthy near infrared light, by a judicious choice of the frequency cutoff for the window through which light exits the lamp.
Even with enough near-infrared light, the efficiency should be a few times higher than for classic incandescent lamps, though not as good as for LED lamps. Presumably, one could reach an efficiency similar to that of the compact fluorescent lamps (which was about half of that of LED lamps), for such an incandescent lamp that also provides near-infrared light.
Despite saying the visible flux component is "small" and that the tungsten lamps "were not expected to [be used] as task lamps," Figure 6 (a) and (c) shows... desk lamps right at the work stations like task lamps! Not only is this experimentally unblinded, but the visible light immediately in front of the test subjects is noticeably brighter and warmer. The effect could simply be due to reduced eye strain.
What would James Randi do? "Extraordinary claims require extraordinary proof," and unfortunately this isn't it.
This would be more interesting if they add a visible light filter on the lamps so they only emit infrared radiation, and have an identical double-blind control with a 60 watt heater bulb so it emits no SWIR but the same radiant heat (which could confound and/or unblind).
Yes, there is something obviously wrong with most LED lights, but it isn't too much of short wavelength light, but on the contrary. It's the near absence of cyan light in most LEDs. Our eyes are by far the most sensitive to it, the majority of receptors in the eye are sensitive to it, and we may focus primarily on it (focus differs for different wavelengths). This is how you get the feeling of something being wrong with your vision as you for example walk into a mall, and so on.
If anything, higher temperature lights seem to make it better, not worse, but the problem will persist as long as the cyan hole stays there.
> If this is done with a halogen bulb, which is a type of incandescent tungsten bulb, the filament lasts for a longer period as evaporated tungsten is redeposited on the filament rather than blackening the bulb glass. Hence, using a halogen bulb at lower voltage is a realistic alternative in terms of health and energy consumption.
Unfortunately, as I understand it, the redepositing action only occurs at high temperatures.. It's a chemistry thing. I have been led to believe that running halogens at low voltages will cause the bulb glass to blacken sooner. See https://en.wikipedia.org/wiki/Halogen_lamp#Effect_of_voltage...
Ban on all fluorescent tubes (T5 and T8 lamps) from August 24, 2023
Ban on all CFL lamps from February 24, 2023
Extension of the exemption granted to HPD lamps from 3 to 5 years
Extension of the exemption for special purpose lamps from 3 to 5 years
We many times see some people reporting that they clearly see lower quality LED light flicker and is really distracting to them and even causes them headaches.
Now, I didn't see this until recently (unless in failing lights) in the right conditions. If the light is very, very dim: For instance, only 1 light on in the night, and you are in a division far away from the light so that it's extremely dim. There, I could finally really see it flicker.
I've replaced that light for a better one and the effect went away.
People really should get it and stop sharing newly published papers to the general public. The value of one single academic paper is exactly 0. Even a handful of such articles still has 0 value to the general public. This is only of interest to other academics (or labs, countries, etc.) who may have the power to reproduce it in a controlled environment.
Be very skeptical of correlations like this that have dubious or poorly understood causation. Be even more skeptical if they are about day-to-day stuff that would likely have large swaths of people able to reproduce something like it on huge scales yet they haven't. Extraordinary claims require extraordinary evidence.
there may be more light (photons) but their spectrum is too limited for my eyes to see like halogen, etc.
I still only use compact florescent in my home, led is useless to me