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The original claim is that exposure after sunset upsets your circadian rhythms. Now it's been twisted into "OMG! blue light will blind you". The good news is that this will hopefully put the nail in the annoying blue indicator LED coffin. All the cool kids are using white and RGB LEDs now.


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Affects circadian rhythms, damages retinas: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4734149/

Evening use of LED screens alters circadian rhythms and has a detrimental effect on cognitive performance: https://www.physiology.org/doi/full/10.1152/japplphysiol.001...

You can find more. Wikipedia has 40 citations here https://en.wikipedia.org/wiki/Effects_of_blue_light_technolo...

Your counterpoint is irrelevant. Non-artificiality isn't a guarantee of benefit: if you go outside in the daytime and look at the sun you'll go blind.


(f.lux author here): the initial part of this press cycle was effectively scare-mongering, and was later mostly retracted by Karunarathne. See https://www.theverge.com/2018/8/17/17724658/screen-time-blue...

This (older) article says: "we don't spend that much time staring at the sun". But just seeing the blue sky gives your retina about 50x the dose of blue light (hazard) as a normal LED display.

Blue light hazard is generally considered to be "reciprocal" which means for most doses, you can measure total energy (power * time). So it is easy to argue that one hour spent outdoors (not staring at the sun, just doing normal stuff) gives you more dose than 12 hours at a computer. So for light seen during the day, nobody has yet shown that seeing a computer is harmful, and the risk should be lower than spending an hour outdoors.

At night, it's another story, and there is not clear evidence here. The retina experiences daily circadian rhythms, and so risks to your eye may be enhanced by bright light seen at night. Less light at night is good for your circadian clock, and it is almost certainly good for your eyes too.


> high-efficiency blue LED fixtures

The extra blue is probably screwing up the circadian rhythms of humans and animals:

* https://www.health.harvard.edu/staying-healthy/blue-light-ha...

* https://www.npr.org/sections/thetwo-way/2016/06/21/482936520...


Wasn't the whole blue light thing disproved about a year ago? IIRC more light late at night disrupts the cycle, but the color of it was irrelevant.

> "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.


> blue light definitely messes with your sleep cycle

...and kills your eye cells.


This is confusing to me, would love if someone helped elucidate the details. My previous understanding was that bluelight is harmful because bluelight visually interferes with the body's circadian rhythm by leading the body to believe it's still daytime when it may not be.

This article says that "any bluelight is bad", is that incorrect? I don't understand, isn't bluelight measured as light on the 450nm range of the electromagnetic spectrum, whereas visual sunlight ranges from 400-700nm? So, is the thesis that light at 450nm from the sun is only emitted when the sun is highest in the sky, for a few hours a day, whereas bluelight from screens is ever present—causing the circadian rhythm to go out of whack (?).

The article also states that blue light on any part of the body may cause mitochondrial damage. I wonder if the most proactive biohackers would be inclined to wear long-sleeves at non-peak hours to counter this problem. [0]

Maybe this is why Dave Asprey is seen always wearing his blue light blocking glasses, even during daylight hours.

I am also not so inclined to dismiss this data because it only addresses fruit flies. It seems natural to believe that the closer we get to following the circadian cycles we evolved alongside with, the more likely our bodies are to behave optimally. Sure, we may be more resilient to these types of stressors than fruit flies, but, we already know that obeying circadian cycles is a key component to achieving better health, and the work of this paper just seems to push that idea a bit further than we may have originally been lead to believe. It doesn't take much of a stretch of the imagination to guess about how these factors could affect us.

[0] https://www.nature.com/articles/s41467-018-02934-5


It always seemed to me that these "blue light harms your eyes" proponents had never spent a day outside.

Allegedly blue LEDs are supposed to be really disruptive to sleep (not just due to brightness but due to wavelength. Body interprets blue as daylight and red dusk or something)

Yeah I couldn't be around lights that intense later in the day. Same thing with computer screens...I have them dim and disable blue wavelengths around sunset.

> 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

Maybe not.

https://www.unibas.ch/en/News-Events/News/Uni-Research/Light...


I've been listening to the Huberman Lab podcast, and he seems to think that blue light filtering during the day is a terrible idea in terms of your body's natural rhythms.

> According to the team, using dim, cooler, lights in the evening and bright warmer lights in the day may be more beneficial to our health.

so it's actually the opposite to the current common belief. it should be blue at night, warm during the day :)


> A blue light tells our brain "we're in the morning, wake up up!" while a soft yellowish light tells the opposite "slow down, dusk is coming".

I have no idea where you live, but in my sunny location the sunlight streaming through my window that wakes me up every morning is overpowering yellow. I associate "bluish" with darkness rather because evenings do become "bluer" before becoming dark. In fact, I have a colour changing LED bulb in my room, and I switch to yellow lights if I want to work longer at night - I find it more soothing on the eye, while it helps me be more "awake". The whitish / blueish light of the LED actually makes me feel drowsy.

On computer screens, I find that whitish / blueish light strain my eyes more, and thus apps like Flux - that change the display to a more yellowish tint - is more soothing and less stressful on the eyes.


> 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 thought the issue for macular health wasn't "blue light" in particular, but high-intensity light energy in general: https://pubmed.ncbi.nlm.nih.gov/29044670/


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)


"Contrary to common belief, blue light may not be as disruptive to our sleep patterns as originally thought"

Emphasis on "may".

"Our findings suggest that using dim, cooler, lights in the evening and bright warmer lights in the day may be more beneficial."

Emphasis on "suggests".

Also, the study's title itself.

"Cones Support Alignment to an Inconsistent World by Suppressing Mouse Circadian Responses to the Blue Colors Associated with Twilight."

Emphasis on "mouse".

Science oozes back and forth. You should not strongly interpret individual studies. Debunked is a strong word here.


"But ophthalmologists aren’t worried. The blue light emanating from the sun drastically overpowers any rays coming from your screen. And so far, all of the research on how real human eyes react to blue light has failed to link screens to permanent damage of any kind. Blue light’s most concerning effects still seems limited to sleeplessness."

OK, so what else is there to learn?


Last I heard there isn't strong scientific proof blue light is bad for you. I mean if you go outside at night the moon looks awfully close in color to a phone screen...
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