There’s a lot to learn about how blue light affects our eyes | Hacker News Reader

There’s a lot to learn about how blue light affects our eyes

popsci.com

101 pointsALee25 comments

(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.

Flux is amazing I just posted below, always surprised this is not a default install for devs. thank you for the authorship!

OT: I used flux ages ago. You seem still to be active since you intro'd yourself als the flux guy. Out of curiosity, why should anyone still use flux nowadays when all OSes have time-based red-shifting built-in?

I still find it better than the built-in night-shift on MacOS.

A greater deal of blue filtering was available on f.lux last time I used it. Unfortunately since it did not allow for setting hours other than the local sunrise and sunset times, it wasn't useful to someone like me that suffers light exposure insomnia during the months with longer daylight hours. Even though my home has been setup to accommodate this, f.lux, at least last time I used it, would not. The built in feature in my OS happily lets me choose for myself when to filter blue instead of denying me that choice.

It sounds like you've moved on so this likely isn't useful, but f.lux lets you override the GPS coordinates, so you could likely just negate your latitude to shift to your location's winter schedule.

Personally - more options, more modes, more control.

Thank you for making f.lux. I've been pointing friends to it for years. f.lux also inspired an open source program that I've been running on Debian. http://jonls.dk/redshift/ https://en.wikipedia.org/wiki/Redshift_(software)

than you for f.lux

Just dropping by to say thank you for f.lux! I'm able to keep hacking at night because of it.

More accurately, you're able to stop hacking at night and thus have energy for hacking during the day.

Thx for f.lux it's great. A little question : would it be possible to implement an Exposure slider in f.lux ? Sometimes you want to have even lower luminosity than the lowest backlight value possible, and sometimes in plain sun one could want to brighten its screen even if it means smashing the colors (saturating the rgb channels). Is there a way to sponsor this feature ? Thanks !

Taurine found in the RedBull drink and body building supplement will help repair the damage bright light carries out on your eyes, its also a nootropic helping users to lay down memories when they sleep, dream frequency including remembering dreams will also increase, dreaming is a sign that memories and learning is taking place amongst other things. Re no one showing a computer screen is harmful, the blue light from devices can keep people awake for longer including when using F.Lux, and the circadian rhythmes are such that it supresses the release of melatonin the sleep hormone which typically starts to rise from around 21:30 peaking around 01:30 before dropping off sharply. This time various depending on where you live in the world and day of the year as its link to sunset times. Melatonin is also 4x more potent as an anti-oxidant than Vitamin C and also helps increase the release of mesenchymal stem cells which aid the repair process carried out when we sleep. So yes studies have shown computer screens, smartphones used late in the evening and at night can cause damage to the body. Its not exclusively blue light which keeps people awake either, red light can also keep people alert, this is why vehicle brake lights are red, red being associated with danger which arouses the mind and body. One of the problems with the human body is it can also function adversely if expected light is missing from the light spectrum of the source. This will become more common place with the use of narrow band light sources like LED's when compared to the sun. The body has evolved over thousands of years in an environment which we are changing rapidly through technology and evolution can not keep up with man made changes.

Lots more information about this in Richard Feynman’s Color Vision lecture:

http://www.feynmanlectures.caltech.edu/I_35.html

Wow, I just read the first section (four or five paragraphs) and learned two new things already. Is this representative of Feynman’s writings? The level of both clarity and information is impressive.

If you haven't yet read Feynman, you're in for a treat. It's not common at all to find someone with both great domain knowledge and great communication skills.

Android 9, and maybe 8 but I never checked, offers an opacity setting.

I leave the filter on, and the setting to a point where I see an overall display color temp close to the old NTSC value: 6,500k. Being an 80's kid, values centered on 6,500 were common. I remember the shift upward becoming more common. It was intense!

For people who were viewing during the cooler periods, warmer displays are something one can feel. It is a lot like the feeling one gets when stepping outside after a long, device free, period indoors.

A 6,500 ish display temp presents an orange tint when compared to most device defaults seen today. For me, this is almost unnoticeable after a brief time. I adapt quickly and basically become unaware.

A nice, darker phone theme helps.

I really like the warmer settings, but they do have an impact on me. Sleep and eye fatigue. For most things I find I just do not care and will save a really warm session for a movie, or other special time.

I bought a monitor with a "Low Blue Light" feature built-in. At first I didn't use it, but after reading up on it I decided to give it shot. I have three monitors on my desk so I reduced the blue on the other two manually.

It was a bit hard to get used to at first, it seemed to make things a bit more green to me, but after about a week I switched it off and it only took a few minutes to notice the difference. My eyes felt a lot more strained with it turned off.

If I were doing graphic work I suppose I'd have to turn it off, but I'm not so I don't worry much about how it effects the little bit of UI work I do.

Do these monitor features have any advantage over f.lux, Windows/Apple Night Light, or similar software implementations that work on any monitor?

The obvious one is they work for input sources that don't support those software programs, e.g. game consoles, TV hardware, etc. (Now why you would WANT that feature on those input sources is none of my business.)

Well, for one thing they (at least in ASUS's case) appear to do the opposite of Night Light / flux by subtracting the blue channel rather than increasing the red channel. This means at first the image looks a tad green/yellow-er, but you get used to it much more than Night Light's red tint. I've had it for a year now, mostly on the highest level (certified as "70% blue light reduction") and I still sometimes check that it's on. (But once you see the onscreen UI in a blue-ish white it's very obvious)

My eyes also get a lot less fatigued with it on compared to OS features/flux, even after tuning my monitor & room brightness accordingly with a colorimeter.

A lot of it might come down to certification and blue light reduction methods at the monitor level. In ASUS's case they claim to be certified by TUV Rheinland[1].

[1] https://www.asus.com/Microsite/display/eye_care_technology/

Mentioning Flux - a free blue light reducing app that is beautiful and functional - as I’m always surprised how many people haven’t heard of it.

Takes exactly 5 mins to get used to it and after working with flux on I’m amazed how overwhelming default monitor settings feel.

https://justgetflux.com/

On Windows the pointer remains white so once you get used to the rest of the screen (a few minutes the first time, and pretty much instantaneous thereafter), the pointer appears to take on this very potent blue. Switching flux off at this point is damn near blinding, so it is definitely having a profound effect.

"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?

My normal glasses have the blue light filter, not my sunglasses though.

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