Blue light is very, very bad.

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hank
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hank
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Here’s a short summary history of the field:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2831986/

Environ Health Perspect. 2010 Jan; 118(1): A22–A27.
doi: 10.1289/ehp.118-a22

What’s in a Color? The Unique Human Health Effects of Blue Light

Quote:

… Hastings and Sweeney’s paper, published in the December 1958 Biological Bulletin, gathered dust for decades. No one thought these findings might hold any relevance for humans, whose circadian rhythms were then widely believed to be relatively insensitive to light.

But scientific discoveries in the past two decades have changed all that. Not only does light reset the human circadian rhythm, but the same blue light that has the strongest impact on dinoflagellates has equal power to reset our own clocks—although most visible wavelengths can reset the clock, the blues do the job with the greatest efficiency. …

… In 1976, Czeisler’s advisor attended a closed meeting of some 18 top circadian scientists at the Max Planck Institute, and Czeisler, then a graduate student, tagged along. As the scientists toured an apartment in the bunker that was illuminated by table lamps, Czeisler asked a question that he says in retrospect seems ridiculous but that helped turn the field on its head. “What’s it like when it’s dark in here?” he asked. “‘It is dark in here,’ Dr. Wever responded,” Czeisler says.

It turned out that by “dark in here” Wever meant the overhead fluorescents—which represented daylight when the researchers turned them on each morning—were turned off. The table, kitchen, and bathroom lamps, which subjects could control themselves, weren’t believed to influence circadian rhythms. But apparently they did.

From 1980 to 1987, a series of papers came out that changed the field’s thinking on how human circadian rhythms are entrained…

… Czeisler was able to suppress melatonin secretion and shift circadian rhythm in the latter patients by exposing them to bright light. “That just blew us away,” he says.

But it didn’t blow away skeptical journal editors. One who rejected the paper said, “These people aren’t really blind, they are lying,” according to Czeisler, despite the subjects’ failure to perceive a neuro-ophthalmologist’s brightest light when he shined it directly into their eyes. After 5 years and 20 rejections, the New England Journal of Medicine published the paper 5 January 1995 after first making Czeisler test more subjects and cover both their eyes and their whole bodies, “just in case light might be penetrating some other body part.”…

hank
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Hat tip to Soylent News
===============

Let There be ‘Circadian’ Light | | from the Oh dept. | | posted by Fnord666 on Saturday February 22, @20:24 (Science) | | https://soylentnews.org/article.pl?sid=20/02/22/0338234 |
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[0]martyb writes:

[1]Let there be ‘circadian’ light:

Researchers said the wavelengths at sunrise and sunset have the biggest impact to brain centers that regulate our circadian clock and our mood and alertness.

Their [2]study, “A color vision circuit for non-image-forming vision in the primate retina,” published in Current Biology Feb. 20, identifies a cell in the retina, which plays an important role in signaling our brain centers that regulate circadian rhythms, boost alertness, help memory and cognitive function, and elevate mood. (See [3]interview with lead researchers)

[…] Lead author Sara Patterson, a graduate student in neuroscience at the University of Washington School of Medicine, said how we set our internal clocks to the external light-dark cycle has been studied a lot. But how the changes in the color of light affect our brain has not.

“Color vision used for something other than color perception was the most exciting part for me,” she said.

In the study, Patterson and colleagues identified a cell known as an inhibitory interneuron or amacrine cell in the retina, which signals to photosensitive ganglion cells that affect our circadian brain centers. The researchers said these amacrine cells provide “the missing component of an evolutionary ancient color vision circuit capable of setting the circadian clock by encoding the spectral content of light.”

Patterson said so little is known about rare retinal circuitry that it was possible to find a new blue cone cell. She said there is a lot more to be discovered about how blue cone cells are projecting to other areas of the brain.

Journal Reference: Sara S.Patterson, James A.Kuchenbecker, James R.Anderson, Maureen Neitz, Jay Neitz. “A Color Vision Circuit for Non-Image-Forming Vision in the Primate Retina” Current Biology (DOI: [4]10.1016/j.cub.2020.01.040)

The entire article is available on [5]Science Direct.

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[6]Original Submission

Discuss this story at:
https://soylentnews.org/comments.pl?sid=20/02/22/0338234

Links:
0. https://soylentnews.org/~martyb/
1. https://newsroom.uw.edu/news/let-there-be-circadian-light
2. https://www.cell.com/current-biology/fulltext/S0960-9822(20)30084-1
3. https://newsroom.uw.edu/resource/science-behind-circadian-lights
4. https://doi.org/10.1016/j.cub.2020.01.040
5. https://www.sciencedirect.com/science/article/abs/pii/S0960982220300841
6. https://soylentnews.org/submit.pl?op=viewsub&subid=39314

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So many different takes on this... but I went and downloaded an Android app called Sfilter. I kept going through the color filters until I found the one that made my eyes the most comfortable. Does the screen look like crap? Well...yeah... but my eyes are much more comfy, blue light or no.

"I am the flashlight king! I can light anything!"

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