The human lens filters most light at the peak of the given spectrum for free retinal (383nm), and so once you get to 450nm like an LED, the hazard data in the visual range is 100x less sensitive, see Fig 1 here:
It bears repeating that computer screens have <5% the hazard-weighted irradiance of a blue sky. (Can't make a direct comparison with lasers.)
Not sure the conversion to white light is correct, and it is unclear to me right now if this much retinal is available in vivo.
If you guys ever wanted to figure out your app on a smart TV (or apple TV), I know there'd be a lot of thankful people!
Also, I'd love to contribute to the ongoing dev of f.lux (I don't think I've had to pay for it?) How might I?
Huge thanks to the author from me as well!
Then you can assign it to the Accessibility Shortcut and turn it on or off by triple pressing the Menu button.
Also, you can be below threshold for circadian responses just by being very dim.
I know very little about this so I'm genuinely curious.
"15.4-inch (diagonal) LED-backlit display with IPS technology; 2880-by-1800 native resolution at 220 pixels per inch with support for millions of colours"
What possible laptop alternatives are out there that are better for eyes?
One example of this is hiking in fresh snow for hours, no sunglasses, meaning exposures well above 10,000 cd/m2 to "white light".
Computer screens are way dimmer - an hour of iPad use is .0365 J/cm^2.
http://www.nature.com/eye/journal/v30/n2/full/eye2015261a.ht... is a good summary.
For long-term exposure (AMD risk) we have very little data, so understanding the mechanisms (such as above article does) can help.
If so I would argue f.lux does a lot more. For one thing you can choose the hue it goes to, but also unlike the Windows 10 one which (AFAIK) is simply on/off, f.lux will adjust based on a schedule which means that you don't typically notice the effects (as the change happens slowly). This, combined with the ability to change damn near every parameter it uses, makes f.lux significantly better.
Edit: apparently windows does have hue adjustment and sunset/sunrise activation/deactivation available. TIL.
EDIT: HN is becoming more like Reddit every day, I see. Ridiculous. Down-voted for pointing out the existence of helpful features. EDIT: might have been my fault.
And I assume you understand that since you edited that line out.
Since our update last year (v4) f.lux stopped doing this and does a lot of other tricks to reduce impact on framerates too.
I presume that they used a laser because they anticipated that it would potentially take years to see a result from a non-coherent blue light source, far exceeding their available funding, patience, and ability to keep uncontaminated cell cultures going.
Applying a blue laser with unknown irradiance to a retinal cell line from a single human genetic source in vitro is very, very far from proving a link between blue light and diseases such as macular degeneration and RP.
All this demonstrates is that coherent blue light is capable, under certain circumstances, of interacting with retinal to produce cell damage.
Any relationship to human disease on the basis of this paper is pure speculation. Advising people to wear "blue blocker" sunglasses or avoid cellphone screens (or take Vitamin E!) is pure fantasy made up by the scientific press to sell your retinas.
Isn’t the other “sniff test” that we haven’t seen a huge increase in age related retinal diseases since the introduction of computer monitor and handheld devices?
If these sources had such a big impact, it would be obvious from incidence numbers.
I used f.lux for 2 years. I found that I would stay up way past my bedtime, glued to the computer screen, and end up with correspondingly tired & fucked up eyes.
So I got rid of f.lux, and after that, I would go to bed at a more proper time. When the screen starts irritating my eyes, it's a direct indication that it's time to close the computer and get the hell to sleep. Ever since that, my eyes have done a lot better, because I no longer push to stay up way past my bed time.
So the only solution I have figured is to be regimented about my screen time. I love working late at night and now have to tell myself to turn the work off. That kinda sucks.
Btw, It happened both with my previous laptop with LCD screens and the current LED screen.
For a few months I got hooked to Mobile gaming, and that just multiplied the problem! So I drastically cut down on my mobile time and that helps. My mobile had an LCD screen btw; so LED or LCD doesn't seem to be a factor for this particular problem.
I also found retina display helped reduce eye strain.
Thank you for reading/writing out your interpretation of the article so clearly (highlighting points others are likely to trip on not coming from a related background)
Part of my ritual of setting up a new monitor is to turn down the brightness and increase the contrast. They almost always default to very bad values. Brightness, temperature and green/blur balance are all off for an office setting.
In the worst case the backlight was capable of outputting twice as much light as I really needed.
I suspect part of it is also planned obolescence --- when the backlight is running at full brightness, its lifespan is greatly decreased. Now the aforementioned monitor is approaching 15 years of age and brightness has reached 20/100, so there's still plenty of life left in it.
I wouldn't mind having to create multiple display profiles for this, but right now, flux seems to only support non-LUT based, Matrix based calibrations and only if they have VCGT headers, and then only based on those headers.
But this seems highly problematic.
Take a look at this page here for why:
I assume you based the current mechanics of f.lux when it comes to handling color profiles based on what the quickgamma homepage says about this:
Apple has been using the LUT since many years for its operating system built in color management. In fact, Apple has registered the private ICC Profile tag video card gamma table (vcgt) with the International Color Consortium (ICC). This tag is used in a dedicated Monitor Profile and holds the gamma values, which are then loaded into the LUT by a loader program.
Hardware based Monitor Calibration Systems also use the vcgt tag, which in this case contains the correction data to achieve the monitor calibration. Because Windows did not provide a LUT loader, each calibration program had to provide its own LUT loader program. ...
Things changed when Windows 7 came along and provided its built in calibration loader, which not only loads the LUT at system start up, but also takes care of Standby and Hibernate.
As you might notice, the two stories from those pages seem to conflict?
Right now, when I use Windows to load my icc profile, I get correct colors. Same if I use the DisplayCAL profile loader.
However, if I start f.lux during the day (where f.lux shouldn't mess with the colors at all) I get semi-incorrect colors - they end up "more correct" than when I have no color profile loaded at all, but still VERY incorrect.
Is what you want more like "don't mess with the operation of color profiles when f.lux is disabled or otherwise shouldn't be adjusting the screen?"
I was very happy when I found f.lux. Finally something replacing my own tool I wrote for my Atari.
The main benefits with f.lux is you can easily set brightness and on/off with keys in any program or game, no need to navigate with mouse in menus.
Figure 3 in the paper seems to show that 500 nm is safe, and that melanopsin has high absorption at 500nm, which has important effects on circadian rhythm.
Anyone more knowledgable than me know if this setup is safe?
But the main thing you'll want to make sure is that you can get enough light. There is some evidence that >200 lux with this wavelength will help, but most light therapy uses tons of light (1500 melanopic lux or more):
I'm guessing melanopic lux is the lux output weighted over the spectral absorption curve of your eyes?
Some napkin math: I have ten 3W LEDs, and each might produce around 1000 lux when fully driven. If we drive each at half strength, and half of the generated lux is melanopic lux, that's 2500 melanopic lux.
Melanopic is weighted by the non-visual response in the eye, and this number corresponds pretty closely to the spectrum that drives circadian effects, and likely, mood. So whereas an incandescent might be 0.45 melanopic lux per visual lux, a really blue sky (or a 500nm LED) is around 2.0 "M/P".
I originally purchased these nice LED strip bars with enclosure in blue, but after reading this site by the manufacturers of a commercial green therapy light, I was convinced to switch to turquoise/cyan.
Turquoise isn't that popular so I wasn't able to find any strips/bars, and I got these individual 3W bead LED modules instead.
For the Hue integration, I'm using a Mesh Bee + UartSBee v5 with firmware from PeeVeeOne. It outputs PWM, and I'm hooking it up to a cheapo constant current LED driver I got from Aliexpress. Since all the LEDs need to be in series for a constant current driver, I'm probably looking at a ~20V power supply to power the whole thing.
My bedframe has a headboard, so I'm planning on 3D printing some mounts that clamp on top.
If it were me, I'd probably run everything in parallel just to keep the voltages lower, and be able to use readily available power adapters.
Aliexpress has a PWM controlled constant current driver that takes 5-35V in and outputs 350ma max . 10 of them are $20, so they're not too expensive.
At a forward voltage of 3.3V for the LED's, you'd be looking at slightly more than 1W per LED at 350ma (P = VI).
Those constant current supplies probably have an efficiency of maybe 66%, taking that into consideration, I would think a 12V 2A power supply would be enough to drive the entire thing. And that could be a wall wart that you get at the local hardware store.
I already got the board you linked, supposedly configured for 700 mA. Haven't tested yet. The datasheet for the part says it can go up to 2A, so I could potentially modify the feedback circuit for 1A, which would reach the full 3W rating of the LEDs.
One issue with that driver chip is that the PWM/enable is active low, so I think I may just stick an inverter on the output of the Mesh Bee. The SDK for the NXP part has changed since the ZLL repo was updated, and I haven't had much luck getting it to compile myself.
The easiest way to test it is to get a multimeter, and put 1A through the led, then measure the voltage across the diode, and that will be the voltage you're targeting. (or you can just use one of the 700ma current regulators for a good estimate, placing the enable to ground.)
Also keep in mind that those current regulators are buck converters and they're not 100% efficient (no regulator is, really). So you're going to want to add 20-30% more power at a minimum on top of the load you're planning on driving with it.
And if you're going to drive 12V of LED's, expect to need 15-18V to drive the buck converter. That's because of the way buck converters work.
The feedback voltage on that chip is a fixed 1.2V and that's used as an internal voltage reference (I guess because they didn't add one into the chip).
They have a circuit diagram for that part, and it looks like CS and Rcs are the most important things on that sheet. CS is the "Current Sense" that measures the voltage across the current sense resistor (Rcs). They give the formula for Calculating Rcs to get to 1A (ILED = 0.155 / Rcs), and I get .15 ohm for Rcs at 1A.
Then you can either replace it with another sense resistor with something like this , or an appropriate length of copper wire  to give you the correct resistance.
As far as the PWM/enable inversion goes, just invert it in software. 100% full duty cycle would be off and 0% would be on. If you have a Raspberry PI laying around you can easily set one of the pins to PWM to test out your inverter code .
I'm going down a similar path to build a UV light box for exposing PCB's and the like.
Best of luck!
Edit: You might need a mask to create a slit of light so you can see the spectrum clearly.
I'm sure there'll be _some_ blue light. I don't know if a prism would be high resolution enough to tell if it's a dangerous level.
I already have a normal Hue bulb next to my bed on a schedule, similar to the wake up light, but a light strip right above my head seems more appealing to me.
I mean the delayed phase sleep disorder. Will talk to the doc about it.
Can someone explain why it would be worse to look at a cell phone in the dark? It's emitting the same blue light (or less, if the display gets dimmer) as it is in a bright environment. Why is that light more harmful in a dark environment?
It is this principle that camera apertures are based on.
Now if you have your pupil wide open in a completely dark environment and put a 100% brightness screen at ~10cm of your eyes, what do you expect will happen ?
Our eyes are made for nature, that means day and night, now we have technology that is akin to a handheld sun and you use this at night at 10cm of your face, our eyes are simply not equipped to handle this.
Indoors, I use about 30% brightness. As the day gets dimmer, that slides down to about 25%. If I'm reading something in bed, I start at about 10% and as my eyes adapt, go down to 1%. When I'm finding it hard to keep my eyes open, I take that as my signal to go to sleep. Am I ridiculously unusual?
You aren't unusual for trying to prevent your eyes from being harmed. If you were, an article which helps inform on the topic of eye care would not be popular.
I absolutely notice a blue refraction from car headlights when driving at night. I keep thinking I'm seeing a police light from somewhere. It's fine, just interesting. Well, after looking at a few lens coating websites, and realizing my lenses reflect blue light back at me if I have a light source to reflect, they're obviously blocking blue light -- cool!
I've never been much for f.lux style color shifting, I HATE the obviously inaccurate colors. I also wonder if we'll find that some of these technologies don't work nearly as well as a blue filter, and that perhaps the light just LOOKS less blue.
But I'm sure glad to have glasses that now block some blue light. Also, it validates my desire to keep the blinds open at work; I have LOTS of light coming into my cubicle area. Sometimes it's even a bit annoying but keeping my pupils small should help.
I never work in a perfectly dark room. My office is next to a window, both at home, and at work. The lights are on. Plus, all of these things help keep my pupils small which apparently helps prevent the blue light harm to begin with.
Why is it that you prefer the incorrect colors without flux to the incorrect colors with flux?
Sounds like you prefer cool color temperature which is no more correct than warm color temperature.
Colors appear to change dramatically under different lighting conditions, but we accept these changes as normal given context. Changing the white balance on your screen is no different. It's not inaccurate, it's just rendered as if in different lighting conditions.
We have the ability to adapt to different color temperatures and perceive the relative output, but we're still missing information when shifted from the full spectrum daylight we evolved with.
Consider a recorded rock song: if we gradually apply a low pass filter of increasing strength, the high frequencies will be cut. We'll still be able to hear and recognize the cymbals, for example, but the stronger the filter, the less accurate the output.
Just because we can recognize relative colors under different lighting conditions, it doesn't mean that they're still accurate when we remove information.
That is a really interesting distinction! Blue is a color derived by social consensus, but it is also a particular wavelength of photons. I'm curious about what's there if we dive in and examine what specific wavelengths of light (numerically) cause damage, and what is the overlap with what we typically consider the color blue. I'm sure it's not one to one.
I think some ultra-bright headlights are actually slightly blue.
I wonder how significant the difference is between pupil dilation while looking at a bright phone in a dark room and while looking at a bright phone in a bright room.
I personally can't have the lights off even if I'm watching a movie. Maybe because I was raised without TV, I can't sit still for more than 20 minutes watching entertainment before I feel the urge to do something productive like wasting time on the internet.
I prefer low light, not pitch black. Generally speaking I want my monitor to be the main focus. Same for TV; if I care about the viewing experience I dim the lights. I might even prefer pitch black honestly, but due to the reasons being discussed, the contrast is just too great.
> Don't you feel clumsy, sleepy and uncomfortable when everything is dark?
> How can anybody go more than 10 minutes without needing to use vision to interact with their surrounding environment?
Not sure, tbh. I imagine it has to do with not wanting to interact with the environment most of the time. Ie, what am I going to do with my banister? It's just sitting there.. why do I need to interact with it? Most of my house is the same way. If I'm doing X, rarely do I need to interact with the rest of the house or room.
Does it bother you that there are things behind your head that you can't see?
Eventually after like 6 hours in the dark and accidentally using just one eye for reading- eventually I started to see really trippy and weird visual noise in the dark areas of the room. I also noticed that if shone at the right angle- the pitch black areas of the room suddenly lit up, as though I was giving my over-exposed eye some kind of night vision, which is weird because you'd expect an oversaturated eye to be completely blind in the darkness.
Now this is all anecdotal, but reading screens in pitch black light has always felt bad for me. I don't understand people who insist on watching TV shows or movies in a fully pitch black room. I mean I get why school teachers and home theater enthusiasts do it- but for normal TV viewing, it just seems wrong to me.
Somewhat constricted. They're still more open that if they were in a fully lit environment, even more so in the sun.
The back camera usually has an IR blocking filter, but often the front camera does not. You can check by videoing an IR led (like from a remote control) with the front camera and seeing if you can pick up the flashing when you activate it.
To get a feel for this, point your cell phone at your desk area and take a picture (without HDR enabled). If you can't take a picture without over– or under–exposing the screen or the wall, then your setup is putting strain on the eyes.
Your camera's cell phone barely manages to hold approximately eight stops of latitude. Blowing out that pathetic dynamic range has no grounding in relation to any notion of "eye strain".
That's precisely what makes it a decent tool for detecting lighting imbalance. Just because our eyes mask the issue with high perceptual dynamic doesn't mean it's not straining them.
It's not the easiest mode to find, but works.
From what i heard this is also why sunglasses that don't block UV light are worse than not having sunglasses at all.
I just found this article, which details why f.lux is better than Night Shift. But it's written by f.lux, so it's a bit biased.
I'm guessing both are better than nothing, but is one actually better than the other?
- You have a great deal of control over the blue level. Night Shift's blue level is higher than F.lux's default, and not adjustable.
- Flux transitions more naturally as the sun goes down.
- More scheduling options, "disable until tomorrow".
- the big one: disabling per-app or for full-screen apps. You probably don't want Flux on while watching a movie or binging on a videogame. (I set up my lady friend with Night Shift and watched a movie with her recently, spent the whole film wondering why they made such awful color choices)
(Tested on iMac and MacBook Air, may be different for other screens)
I've never heard blue being a danger other than its effect on the biological clock, so that seems like a pretty bold claim. Ultraviolet, sure...
Though buried in there is something about immune system and vitamin E levels...
I really find it hard to believe that blue light exposure is automatically bad. We have receptors for that specific purpose. Wearing blue light filtering sunglasses all the time as the article suggestions seems a bit ridiculous. Why give up one color entirely?
Never make life changed based on the results of one single study.
But it is perhaps misleading to concentrate on things that are exclusively blue... The real problem is light containing the relevant range of frequencies, which includes many non-blue colors, due to the relative presence of other frequencies. For example, your eyes would probably absorb much fewer relevant photons when staring at an empty patch of sky than when staring at the sun, even though the sun is not considered blue. And looking at the sun does cause unpleasantness.
Ozone doesn't have a smell. What you actually smell is your nose burning. Ozone is a very aggressive oxidizer.
Looking directly at the sun is also a super bad idea.
Wait, what? Do you have a source for this?
This does not sound right. This is what I see on Wikipedia which is also exactly what I was taught in high school:
> It is a pale blue gas with a distinctively pungent smell.
On the other hand the Inuit had to invent snow goggles to prevent blindness caused by the bright sun reflected off the white snow-covered terrain. Like, actual eye damage blindness. That's been attributed to UV but perhaps blue wavelengths play a role as well.
When you look at the sky during a bright day your pupils are narrow and let little portion of the light through. When you look at blue light in the dark - they are dilated and let more light through.
Few things are "automatically" bad. Over time though, effects are cummulative, and there are also breaking points for lots of bad stuff.
But isn't this bad with other consequences? I thought the lack of blue/violet light was the cause of myopia?
Keep in mind that this is age-related macular degeneration. Your photoreceptor cells are protected by the α-tocopherol until "a person's 50s or 60s." You wouldn't need any prophylactic interventions until then.
Would the inverse also be true?
I suppose you could develop myopia later in life as a result of inflammation of the extraocular muscles (orbital myositis), but this would be 1. temporary, and 2. not treated as its own disease, but rather as a symptom.
The cynic in me wonders if the researchers have any ties to VSP.
I don't have any advice except to learn Braille, which I'm sure is not very encouraging. I hope a cure is found soon.
I messaged Cree on Twitter, expecting a very corporate response, but they linked to some studies (which I haven't yet had time to explore.) FWIW - https://www.energy.gov/eere/ssl/street-lighting-blue-light-a... and https://www.lrc.rpi.edu/resources/newsroom/pr_story.asp?id=3... were the resources they suggested.
I would suggest that one problem is that LEDs don't "warm dim" (unless you get some special ones from Philips and a few others), and people tend to dim them less overall.
Does this mean that consuming alpha tocoferol can combat the toxic effect of blue light? If so, at what dosage?
I find it easier on my eyes at night (both laptop and TV), and it has its place since the TV can't run f.lux and redshift.
If anyone is looking for a good pair, I buy mine from Gunnar  (no affiliation).
Blue light blocking: https://www.eagleeyes.com/pages/blue-light-blocking
Computer sunglasses https://www.eagleeyes.com/pages/digital-eye-protection
I use those and they work wonders.
Yes, Macs have a setting to invert the color palette, but that's not useful to me — a lot of my windows are dark; I don't want them inverted, and it makes images unintelligible. What I really want is something that doesn't screw with images, but detects dark-on-light text and maps the colors in such a way as to preserve contrast and even hue.
It took me a long time to figure out the why. I love dark layouts in terms of aesthetics, but I cannot use them.
Without being biased, from what I have read so far, the research seems favorable for dark-on-light as long as proper room lighting is achieved and monitor brightness and contrast is adjusted for it. In poor light conditions, the inverse seems to be true.
While there's a reason for current defaults, everything should be optimized for and have options for both black and dark schemes.
I wonder, though, what the real problem is that you have with dark themes. It could be related to the combination of wide-gamut monitor blacklights and high-index plastic eyeglass lenses. I wrote something about this here: http://scottlburson2.blogspot.com/2016/01/lcd-backlights-and...
Making the text several sizes larger than usual helps a bit. (Like, 20 point instead of 14.)
In theory, you can look at the CRI rating, but in fact CRI only uses a small number of wavelength probes for the test, so a rating of 100 doesn't necessarily mean a smooth spectrum, it could be the manufacturer has tuned wavelength peaks in order to game the test. There are better rating systems being developed, but they're not used by manufacturers or mandated by governments yet.
I actually think it might be the lightbulbs that change colour which could be problematic. I wouldn't be suprised if some of those did generate the colour just with single wavelength blue, green and red sources. Hopefully the better ones would have individual phosphors for each r/g/b source which produces a spectrum which when combined is reasonable.
I would be particularly careful about cheap/unbranded colour-variable lightbulbs. I doubt they've been through much or any consumer testing, it seems you can buy anything straight off the boat from China through domestic web stores these days.
CRI may not be the best rating for spectrum smoothness, but it's the only one we have for now. It's still hard to find bulbs that even bother to rate themselves.
A LED with low color temperature and high CRI should have pretty much the same spectrum as incandescent. If you want really low temperatures look for some retro filament style LED lights.
Is this so seriously a threat to vision that it's worth it? I don't have the sleeping issues with screens some people seem to report, so I wasn't really willing to commit to it over that.
Change the settings. What you should do is take a sheet of paper and put it next to your screen. Then match your screen's white to the sheet. It's only a bit less blue. There's no need to set everything dark orange.
The article mentions wearing them outside, but they work inside as well.
I wear them, and they provide other benefits for me as well (https://news.ycombinator.com/item?id=16529054#16531413)
I have that, and while it is subtle, I definitely can tell it is there. It doesn't ruin general color perception, unlike many obviously yellow/brown lenses. But, it definitely alters the world to have a slight yellow tinge, a bit like you can get from the haze caused by a distant dust storm or wild fire.
It doesn't bother me, but I am aware of it. I actually prefer brown sunglasses and photochromatics because what is marketed as "gray" often looks sickly purple to me.
Maybe dark adaptation can change that, but I haven't found anything about that upon quick unprofessional examination of .
Examples of a GB-R LED backlit display include the NEC PA302W, so they aren't common.