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Comment by ferongr | Hacker News Reader

Is there any proof that the change of color by programs like flux or built-in OS "night-light" features improves anything?

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I'd be surprised if it doesn't frankly. The blue-light effect on the circadian is well documented science. Don't think anyone is challenging that.

...and turning on flux makes the screen decidedly less blue-ish even by a non-scientific eyeballing so I'd be very surprised if it doesn't check out on a broad level.

Whether it delivers the tangible results promised is a different question.

Broadly speaking I've noticed a correlation between late screen time and bad sleep (or rather falling asleep).

>Broadly speaking I've noticed a correlation between late screen time and bad sleep (or rather falling asleep).

Your observation could be due to the placebo effect. That's why a study is warranted. A yellow post-it could have similar effects if everybody constantly said that having a post-it on the display frame prevents circadian rhythm disruption.

Do you get less blue light or do you get more red light?

I use flux like stuff everywhere because it feels better but I never really analysed if there is less blue light.

Your mileage may vary, but as someone with retinal degeneration it makes a pretty big difference. Photons in the red wavelengths of light carry less energy and put a lot less stress on the retina. Screens are pretty unpleasant for me to use unless they have a color filter on them, and it's the same reason I always keep deep red sunglasses on.

I'm not an expert, but somehow I doubt the strain your eyes feel is directly caused by the energy of a photon.

Retinal degeneration patients are all advised to avoid blue light exposure for this reason. Not only is there a great deal of research to back it up, but subjectively blue light also makes the photopsias and afterimages worse.

Can you link a source? I've found a lot of sites claiming blue light is bad, without a real reason. This[1] site seems to support my uncertainty.

[1]: https://www.aao.org/eye-health/tips-prevention/should-you-be...

Also re: photopsias, and strain.

> The wavelength of light may also affect the photophobia percept. Main et al. (103) found that shorter wavelength (blue) light was more uncomfortable for subjects with migraine than for those with tension-type headache or controls. These investigators also reported that longer wavelength (red) light was also less comfortable for subjects with migraine (103).

Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3485070/#!po=0....

Yea downvote me for asking... y'all need to learn to ask.

You said said that even though you were probably uniformed (not an expert) you thought that somebody with firsthand experience was probably wrong.

So technically you learn to need learn (how) to ask.

I'm guessing you wanted to ask something along the lines of: "I would not have thought that. Could you point me to some sources that shaped that line of thinking?"

I have an iPad with True Tone -- I was originally skeptical (the colors aren't accurate!), but subjectively I end up picking up my iPad instead of my phone quite a bit just to avoid the harsh "blue" light. I have no idea what the impact is on my sleep, but it feels like a nice feature to have anyway.

See, that's the problem with red-light reduction software: it seems like it does something nice, but there doesn't seem to be any concrete evidence supporting it other than personal anecdotes of "I can live without this anymore". I haven't seen a study done yet that says "f.lux helps you get better sleep, and not because it makes your phone's colors look horrible".

On my Android phone, you can use night-light which just changes the spectrum of photons that hit your eye. The theory is pretty simple -- since lower wavelength photons have less energy than higher wavelength photons, the radiation ends up having less destructive potential. I would consider that an improvement.

That's not it at all and nobody cares about "destructive potential" of screen-emitted photons, though. The actual reasoning behind shift to lower wavelengths is that our circadian rhythms are entrained by ambient light, with "blue" light being assumed as indicative of daytime and "red" tones – of sunset (ergo, time to ramp up melatonin secretion and prepare to sleep).

> That's not it at all and nobody cares

FYI - macular degeneration and circadian rhythm disruption are not mutually exclusive, and lots of people try avoid both of these things...

But is there actually any scientific proof of something like this? The studies on the effects of blue light concern way different levels of luminous output.

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