> There's extensive evidence that even relatively low levels of light harm sleep quality; blue light from white LEDs is particularly disruptive to circadian rhythm
> In the case of blue pumped LEDs he's referring to bulbs that use a short wavelength LED in combination with phosphor that absorbs the light and reemits it at lower, and broader, wavelengths.
This was part of my suspicion, but I'm not familiar enough to know if that was correct.
> I get the impression the writer's opinions are extremely niche.
I'll be the first to say "citation needed" to what I'm about to say, but I feel like we went through a cycle of "the science is clear: blue light is bad for sleep!" to "actually a lot of that was not good science", so I'm unclear of where the consensus actually is (if I ignore this article).
> Blue light is a type of light that is emitted by the sun and by electronic devices, and it has been shown to cause strain on the eyes and disrupt sleep patterns.
>I'd have said N=1 vs the study out there, but I too work with screens & LED lighting all the time & the "light spectrum" that affects me is not exactly the indoor component.
Yeah my anecdote proves nothing. But for what ever reason they don't seem to impact my sleep. Just throwing my data point out there.
Also my wife hates the sharp white light so we always go for the warm yellow LEDs.
Yeah, these articles are missing the big picture. I've seen too many people cite articles like this while implying effectively that sleep and wakefulness somehow is not related to lighting at all, and that's utter nonsense.
Lighting is VERY relevant to sleep cycles, and there's no doubts about this anywhere legitimate. The most effective is to not ONLY use red-tint in display controls but also have dim indoor lighting AND dark red glasses (darker and redder than even the generic blue-blocking sort). And the effective is dramatic. Like really get sleepy with dim light. It's not subtle, it's about as strong as an effect can be.
Studying merely the question of whether a little more or little less blue affects eye health in terms of serious diagnosable eye conditions is completely missing the point.
> "In addition to its impact on drivers, blue-rich LED streetlights operate at a wavelength that most adversely suppresses melatonin during night."
I wonder if this ends up saving thousands of lives by decreasing fatigue in drivers. The blue light argument seems like absolute hogwash; we're exposed to orders of magnitude brighter blue light every day. It's called daylight, and the streetlights dont't even emit UV.
There was a statement saying that too much blue light can harm the retina and some mentions of sleep-disrupting effects, but I tend to agree that the reasons why should have been given higher billing in the article as they're rather important.
>...excess light at times of the day when the Sun don't shine messes up our evolutionary psycho-biology, causing issues with sleep.
That is folk wisdom in the IT field. At best, it is blue light, but there aren't enough long term studies to conclusively say this. BMJ Open Ophthalmology published a study in 2018 that said blue light could be a factor in eye tiredness, but it also stated dry eyes due to lack of blinking for long periods a more serious cause of eye strain. It also noted very small fonts, low contrast, and medical conditions like uncorrected astigmatism and presbyopia as factors.
Human eyes don't have good night vision, we see best in daylight.
Black text on a white background is best, since the color properties and light are best suited for the human eye. That’s because white reflects every wavelength in the color spectrum. Because of the reflection, our irises don’t need to open as wide to absorb the white light. That leaves our irises in a neutral position and allows us to see with better clarity. This is especially true when white light is contrasted against black, which absorbs wavelengths instead of reflecting them.
Light text on a dark background makes the eye work harder and open wider, since it needs to absorb more light. When this happens, the light letters can bleed into the dark background and cause halation, which makes the text blurry. Our eyes focus better when the iris is narrow.
Additionally, most people are born with some form of astigmatism, a misshaped cornea that blurs vision. For people that have the worst forms of astigmatism, light text on dark backgrounds aggravates the condition. When looking at a light display, the iris closes more, decreasing the effect of the deformed cornea. When using a dark display the iris opens to receive more light and the deformation of the cornea makes halation worse.
On the flip side, dark mode helps with floaters, tiny fibers or spots that appear in a person's vision. These are caused by changes to the fluid in the eye which cause shadows to be cast on the retina. Floaters distort vision in light mode. This condition tends to increase with age.
Also, people with light sensitivity might be better served by a dark background.
Both light and dark mode should be offered for accessibility reasons.
>Pretty sure this is all snake oil — both f.lux and Night Shift. I don't doubt that blue light affects our brains. But I see no evidence that color filter software has any impact.
A color filter such as in Flux and NS removes blue light.
>If the issue is the number of blue photons per square millimeter of our retinas, why isn't it being discussed as such? This means screen brightness and distance from your face would have a much bigger impact than a color filter.
No, it doesn't mean that at all.
Or rather, it does, but it's a moot point. All you're saying is: you can reduce blue light with an orange filter, but you can also go away from your screen or dim it so you can't see it. Or even not use a computer at all.
While all of those things hold, the "orange filter" achieves the same thing (removing blue light) without affecting our ability to work regularly on the computer (increased distance, less brightness, etc).
I'm not sure how people come up with such logic errors.
>FWIW the only person I've known to use f.lux is an insomniac who barely ever sleeps and is always tired.
It's not worth much. It's not supposed to cure insomnia (which has 2000+ different causes), just to keep up with the natural light changes and improve sleep.
Full text in English (I posted a link to the translated version by Google, which was automatically edited to the original):
Munich - LED displays and so-called blue light are not a danger to eyes or sleep. This is explained by the German Ophthalmological Society (DOG).
Blue light belongs to the visible part of the electromagnetic spectrum and is characterized by energy richness. "Nevertheless, the light intensity when using electronic devices is far too low to cause retinal damage to the eyes," explained DOG expert Michael Bach of the University Medical Center Freiburg.
The natural illuminance in the free one with cloudy winter sky amounts to in our latitudes approximately 5,000 lux, on a sunny day up to 100,000 lux. A computer screen, very brightly adjusted, remains at a distance of 50 centimeters, however, below 500 lux. "Even if children sit for hours in front of screens due to corona-induced distance learning, at least blue light eye damage is not to be feared as a result," the vision researcher noted.
Contact lenses that block blue light also did not protect against eye fatigue during screen work better than standard contact lenses, according to a recent study (American Journal of Ophthalmology 2021; DOI: 10.1016/j.ajo.2021.02.010), the DOG said.
Studies: No evidence of health risk from cell phone radiation
Smartphones taboo for young children
Death and illness cases: Samsung apologizes
DOG expert gives the all-clear also in relation to possible sleep disturbances, which could cause the blue light by evening reading at electronic devices. This assumption, too, has since been refuted by a study, he says (Sleep Health 2021; DOI: 10.1016/j.sleh.2021.03.005). Bach therefore recommends simply avoiding maximum display brightness when reading on an electronic device before falling asleep.
DOG President Hagen Thieme thinks it is important to bring these research findings to the general public. "They serve to educate and protect consumers from misleading advertising and unsettling false reports that pursue purely commercial interests," said the director of the University Eye Hospital in Magdeburg.
Note: the top rated post has focused on editorial quality and glossed over the fact that it is narrow band light and cannot be compared as equivalently in wide spectrum terms beyond perception (e.g colour temperature), this is pointed out in the 2nd immediate child by sandworm101.
I should point out that the properties of the light beyond perception _are_ important due to ipRGCs: the mammalian retina contains ipRGC photo-receptors that do not relay images to the brain but are responsible for various reflexive responses. These receptors are sensitive to a wide spectrum of light peeking around blue [1]. Ultimately these ipRGCs release melanopsin which is known to affect circadian rhythm, and is thought to control sleep wake patterns [2].
I expect you've heard about this vaugley before as I have, but what is interesting in the context of LEDs is that ipRGCs appear to respond to more of a continuum of spectrum, so unlike our cones they would be "perceiving" LED light quite differently to our consciously perceived images.
> For nighttime lighting, try to avoid sources with much emission at wavelengths below 500 nm, because these knock out night vision and disrupt sleep cycles.
Moonlight has significant energy at wavelengths below 500 nm [1]. Does this light disrupt the sleep cycles of other primates, or is this something that developed in humans only after we invented "indoors" and started sleeping there away from sources of bluish light?
It's unfortunate that you're being downvoted without anyone telling you why they're downvoting.
The issue isn't brightness, it's the actual color of the light. The tl;dr version is "blue light definitely messes with your sleep cycle." There's a Wikipedia page about this, with several references at the bottom: https://en.wikipedia.org/wiki/Effects_of_blue_light_technolo...
(And I'm sure a search in your favorite search engine will find even more information on this subject)
In the research page linked, there is extensive research on the effects of bright light exposure to circadian rythms, which may indeed alter quality of sleep by altering natural biorythms (note that no effect is produced on sleep itself, but rather on its timing, and this in turn affects its quality).
There is, however, very little research linked to blue light in particular, and it is inconclusive and contradictory. The best source they cite is actually against the hypothesis:
"Occasional claims that the light sources with emissions containing blue light may cause eye damage raise concerns in the media. The aim of the study was to determine if it was appropriate to issue advice on the public health concerns. A number of sources were assessed and the exposure conditions were compared with international exposure limits, and the exposure likely to be received from staring at a blue sky. None of the sources assessed approached the exposure limits, even for extended viewing times."
On a more subjective note, how they bury the actual research below tons of related-but-not-really articles, pop media links, and "explanations" makes me suspicious.
And mind, I do set my screen to redder tones in the evening and find it pleasant and probably helps me set the mood to go to bed, but I don't think research supports physiological or health reasons to avoid blue light or spend money on blue light avoiding, as the OP link seems to say (I don't read German :(
I just looked at the newest article in your list ("Evening use of light-emitting eReaders negatively affects sleep, circadian timing, and next-morning alertness") and
* there was no mention at all about blue light
* the difference between sleep onset of treatment and control group was 10 minutes - with errors of +-13 and 19 minutes(!), ergo there was no measurable effect.
As can be seen the absolute amount of dark blue to blue (380-500nm) is pretty high regardless of wheather conditions. Full daylight is about 10-20klux, so between 3000lux and 7000lux of blue light alone. For comparison: anti-depression lights are about 2000-3000lux over the whole visible spectrum. Yet people sleep perfectly fine in regions where the sun sets at 11pm in the summer.
There obviously may be an effect, but if it exists, it has to be small.
Maybe not.
https://www.unibas.ch/en/News-Events/News/Uni-Research/Light...
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