Submitted title was "Blue light is toxic to human eyes". That broke the site guidelines, which ask you to "please use the original title, unless it is misleading or linkbait; don't editorialize.
Did we not already know about this ?
I remember 5+ years ago blue LEDs were pulled off of the market (at least in France) because the spectrum they emit in is way too close to uv and could burn your macula.
Yes, UV rays cause damage to pretty much any organic matter, that's the reason we wear sunscreen, sunglasses, and why cheap "fake" sunglasses can be harmful for your eyes (the glass is simply tinted and does not filter out the UVs, which is what they should be doing)
edit: the way I remember it is that like any type of radiation, anything that goes into your body stays there pretty much until your death, the only way to keep your "uv capital" in good shape is to be proactive about it, cant do anything retroactively. This is why about 1/3rd of Australians will develop some form of skin cancer in their lifetime.
I just wanted to point out that most cheap (and therefore plastic) sunglasses are actually perfectly fine in terms of UV protection. Polycarbonate is UV opaque.
If you Google this subject there are several websites where people went out and bought cheap an expensive sunglasses and had them tested and reached the same conclusion: UV protection does not justify expensive Raybans.
Black lights used in clubs generally don't have enough power to cause eye damage or sun burn, therefore, I would not be too concerned.
Lights used in something like a tanning bed, can obviously burn your skin and also damage your eyes that is why people should wear eye protection, or do the healthy thing and not tan at all.
When I did research as an undergraduate, one of the MS students in the lab I was working in moved a powerful UV light used to cure glues from the corner of the room to the center and used it without putting a box over it as was standard procedure. Of course, he didn't look at the light himself, but he also didn't announce its use either. I saw the UV light as I was walking through the lab. It was basically a bright purple/blue light. Several hours later I was effectively blind due to pain, which continued for a few days. I basically had the equivalent of a bad sunburn on my eyes.
This was one of several reasons I quit that lab. Since then I've avoided academic labs that have UV lights or lasers because I don't trust that the students follow safety procedures at all.
Well at least a start is to use software like f.lux that reduces the blue levels on the screen. There are also over screen filters and yellow tinted glasses that can filter the blue light.
It sounds like one should use it permanently, and not just at night. But the real problem is the spectral composition of the synthetic white light on screens. Now I want fluorescent backlights back.
Is there any reason to think that narrowband blue is worse than broadband blue? It makes for poor CRI when used as a light source but if the display blue is near the peak sensitivity frequency for blue it should result in slightly less total power being delivered to the eye than an equivalent blackbody spectrum white light.
Use f.lux or an equivalent (most OS have their own implementation by now) that filters out the blue light at software/rendering level, it's not perfect but you do instantly feel the comfort it brings to your eyes.
Been using f.lux for over 10 years and it also helps alot with going to sleep at night. When it's off your eyes/brain thinks that they are in daytime / broad daylight, when it's on I fall asleep 2 or 3 times faster than without.
The benefit of software such as f.lux and Gnome Nightlight is that they turn themselves on at night and off in the morning. It seems like the OP wants to remove blue light at all times, in which case should be handled through your monitor settings. A software solution would be unnecessary.
The biggest problem I have with it is that everything looks so much worse that I just wind up turning it off all the time.
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.
> The biggest problem I have with it is that everything looks so much worse that I just wind up turning it off all the time.
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.
Okay, but that's a trade-off, you're still getting a fair amount of blue light through in that case. How much less blue light do you want? What's optimal for minimizing eye damage if that's a significant risk?
You don't want to eliminate all blue from your life. Decreasing it is good enough. What's the point of making your computer screen red if the minute you step outside in the sun you lose any benefit?
Make sure you change it to the "Slow: Natural Timing" transition speed so the shift is gradual. The faster speeds (which I believe are default) are jarring and too easy to notice.
I've been wondering if GB-R LED backlit displays help? I haven't seen any reviews which compare the LED spectrum vs a standard white (blue)LED backlit display, but it might be something of interest.
Examples of a GB-R LED backlit display include the NEC PA302W, so they aren't common.
So I used to have glasses with a blue blocker filter on them - I absolutely hated every second of wearing them. Literally everything appeared yellow through them - my screens, sheets of paper, even snow looked like it had been peed on - awful. I mean, it's certainly not surprising - they did block blue light after all. But I wore them for 3 months and then marched back to the optician to have them replaced with normal lenses. And the optician has promised that the effect would be very subtle and hardly noticeable in daily use - well, maybe I'm particularly sensitive to it, but the effect was very noticeable to me.
My new eyeglasses have a coating that reflect blue light. They absolutely do NOT shift the color spectrum. You can't tell the coating is there. Perhaps it's newer or different tech. Look into it.
I just don't understand how that could possibly work - it doesn't matter if the glasses absorb or reflect blue light - as long as it doesn't reach your eyes, anything that is normally white will look yellow, as you're not seeing the blue component. You can't filter/reflect blue light and still see it.
Colour perception is not that simple. The visual cortex compensates. It's the same sort of compensation that means that you see the same colours for objects under artificial lighting and in sunlight, even though spectral analysis will show them not to be.
Yup. I don't know how else to explain it. Trust me, I'm very sensitive to color temperature changes. I have 4 pair of eyeglasses I rotate through every day. Only 2 of them have the latest anti-blue coating. You simply cannot see it. I don't know what product it is, but a good example description from Zeiss:
Are you talking about the coating opticians are pushing for "computer glasses" now in the US?
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.
Judging by the relative light intensities of daylight and computer screen light, I would say it will be sufficient to close your eyes for 6 minutes when you are outside on a sunny day to offset 10 hours of computer use.
Maybe dark adaptation can change that, but I haven't found anything about that upon quick unprofessional examination of [0].
The post's URL actually includes links to the sci rep paper and the full text pdf paper is available from there for free for everyone. No sci-hub needed.
This is not a permanent solution because simply shifting the color temperature has the side effect of generating melatonin and disrupting your circadian clock. You really need a daylight white spectrum and not concentrate all the blue-green energy in one blue spike.
To protect your eyes from blue light, Karunarathne advises
to wear sunglasses that can filter both UV and blue light
outside and avoid looking at your cell phones or tablets in the dark."
> To protect your eyes from blue light, Karunarathne advises to [...] avoid looking at your cell phones or tablets in the dark.
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?
Your pupils are more dilated, due to the surrounding darkness, and hence let more light in. If you were to dim your screen enough to compensate, it would likely be too dark to read.
Because of the way your eyes work.
If it is bright, your pupil will be shrunk, to not be blinded by the luminosity.
When it is dark, your pupil will be opened wide up.
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.
My phone (unlike my PC, or a TV) is smart, and thus dynamically alters brightness based on ambient light. It's pretty cool and certainly mitigaets the above somewhat
At least on my phone (LG G5), the lowest brightness setting is still incredibly bright in an otherwise dark room. I use Twilight[0] to dim it further, though unfortunately Google changed Android so it can't affect the soft buttons. (Which is fine for almost all apps because the soft button bar is black, but of course Chrome changes it to white with no way to fix it.)
iOS is the same. Even on the warmest setting and lowest brightness it's still very bright. Unfortunately, there is no app to do anything about it like there is on Android.
You can configure iOS Home button triple-click to invert the screen, so it's white text on a black background. There is a "Smart Invert" option so that photos are not affected.
I'm on X so no more Home button, but good suggestion. For last 9 months I had my phone on grayscale, which was nice, but still a bit high for my taste.
You can also apply an accessibility filter to increase the darkness in iOS. I have this mapped to a triple home-button click and use it all the time (after reading to kids etc)
I recommend, instead of Twilight, to use Lux[0]. It has many settings and lets you completely set your own brightness curve, with "negative" brightnesses that darken your screen with an overlay included. Also lets you adjust color temp, of course. The free version had all the features I needed.
Hmm. If I've been in the dark for a while and then pick up my phone, the brightness hurts my eyes for a moment until they adjust to it. When I put the phone down, it takes a moment before I begin to be able to see things in the dark room. Doesn't that indicate that my pupils were initially dilated in the darkness and then constricted when I began looking at my bright phone?
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.
If it is the delay in dilation that causes the damage, I imagine it's exacerbated by constantly changing dilation as well. Ie, if I'm staring at my phone in the dark, I rarely keep focus on it. I often glance to the left or w/e, thus causing the screen to appear too bright again. Same for laptop-ing in the dark. I often find myself looking at keys, or thinking off in the distance, or w/e.
serious question: Why do people like to do work or leisure in pitch black rooms? 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?
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.
> serious question: Why do people like to do work or leisure in pitch black rooms?
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?
Nope
> 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?
Very personal answer to your serious question (sorry if it isn’t relevant for others): I can’t stand the stimulus caused by light (one of the problems that come with being part of the autistic spectrum). I wear sunglasses at work (because of the bright fluorescent lights above). Being able to work in the dark is a relief.
get some IR leds and illuminate your face and take a selfie in the dark looking at your phone using the front camera.
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.
It's funny that I'm reading this thread because I just went through this exact same thing last night and it was weird. I don't ever make a habit of using my phone in the dark, but I did yesterday and I did at full brightness and for many hours and it did not feel good.
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.
Interesting; when I got 2 new pair of eyeglasses last month, again I fell for the usual "buy all the coatings" spiel. I didn't much understand what they were, but I was told one causes refractions that bother some people.
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.
Isn't blue light important in the mornings for keeping the circadian rhythm aligned? I thought you were supposed to avoid it in the evenings only. Probably it'd be fine for you if you're getting a lot of light, but might be bad if you don't.
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.
We're able to see similar colors under different lighting conditions only because the mind adjusts what you see for lighting. Seems like the same should be true for filters.
What makes f.lux inaccurate? Color perception is relative and if you are in a dark room, your eyes should adjust to different white points naturally. This is the same thing that makes it so a white piece of paper looks white no matter whether you are inside or outside, even though the actual light reflected from the paper has a radically different spectrum in each case.
shrug. Same way the 'average' person does. Looks totally wrong. I notice it from the first minute it starts to shift. I notice it every time I look at the display of a coworker who uses it. I tried it for a few months thinking it would cue me to go home, at least, but I just started snoozing it the instant it began sunsetting -- forget the more extreme ends of the progression.
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.
"Inaccurate" is definitely an incorrect way to describe the colors. The colors are correct from relative colorimetric perspective, you're just changing the white point.
Any 3-color screen will never be true to life accurate. It's always a simulation of the real thing projected into the three dimensions of color that most of us perceive.
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.
Just because "white" can be recognized as "white" under varying color temperatures doesn't mean that the spectrum isn't truncated, and thus less accurate.
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.
The same happens with computer screens. Most offices are under-lit (or over-lit but only if ALL your UI has a dark background).
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".
> Your camera's cell phone barely manages to hold approximately eight stops of latitude
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.
... but I don't put a 100% brightness screen in front of my eyes at night. Do people really do that? Don't they know how to adjust brightness?
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?
It can be beneficial to suppose a perfectly spherical cow.
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.
This isn't weird at all. I'm jealous of your 1%. The default low on my phone is maybe like 5-10% (I don't know how to check this), and it feels crazy bright when I'm in bed.
If you're on Android, I recommend Screen Filter[1] which will draw a semi transparent overlay on top of nearly everything (depending on the phone and/or OS version, it might not dim the status bar, bottom navigation buttons, lock screen, etc.). I use it a lot when reading at night, because the lowest brightness setting on my phone is also too bright for dark-adapted eyes.
Wow, thanks a lot. Just tried it out and I'm loving it so far. I really appreciate the default reversion in case the slider is set too low, as well as the non-linear percentage slider allowing for fine-grained control at lower brightness values.
For iPhones you can set a full screen “zoom” with low light filter on. It’s under Settings -> General -> Accessibility -> Zoom. Set the filter to Low Light, then turn on zoom, then double tap with three fingers to zoom out all the way.
I do for videos because I notice that I just see a lot more. Turning down the brightness is like turning down the light in the room that was filmed in. That's both on OLED and on LCD screens (wish I could go back to OLED, though, but it has gotten fairly rare among cheaper phones).
I use f.lux all day I don't know if I'm particularly sensitive or if it's all in my head but when I turn off f.lux, especially at night, to watch some movie or video I can physically feel my pupils dilate and it almost feels like my eyes go from being at rest to being strained.
I'm using this [0] Home Assistant component. I also use a similar component to slowly turn my lights on in the morning instead of an alarm clock, which works really well.
Same - I have flux setup to be active during work hours (at work) and evening hours (at home) so it's filtering blue light on all my devices. When I accidentally close it or turn it off for a movie, I feel like a vampire in sunlight. I have such an easier time falling asleep thanks to flux.
Before using f.lux fulltime I noticed that I sometimes got headaches after long days in front of displays, so I started using f.lux not only after sundown, but also during the day and it's very effective. There's no way I'm going back. Essential piece of software for me.
I’ve really started to like gruvbox lately. It’s naturally a warm color theme already so I would imagine it should still look good under a heavy blue light filter.
Can someone say if it is harmful to use a blue light filtering software 24/7? I get its use at night, but would using it from sun up to sun down cause any problems?
Only if you never went outside. Otherwise, it shouldn't. Blue light emitting screens are recent, if blue light is off, it's still more light than a book.
But never going outside would mess with circadian rhythm.
You can't develop myopia or hyperopia after your eyes/skull/orbital muscles are done growing. So this suggestion probably applies only to adults.
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.
I don't know about a source—a medical textbook? Those conditions are explicitly caused by the eye being squished out of the "proper" shape for focusing light by the way the skull and extraocular muscles end up developing.
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.
Actually yes. Doctors have told me that I should wait til 25 to see If I am candidate to eye laser operation because that is the average age where people stop developing his muscle eyes.
Check the spec sheet of the bulbs, specifically the color temperature in kelvin. Ignore the "warm white" and similar marketing terms, they are too fuzzy.
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.
95+CRI is an indicator for mostly lack of spikes. Look at Yuji (yujiintl.com), they seem to be the only ones selling actual high-CRI LEDs with sane pricing (i.e., no ideological markup).
I'd like to try one of these out, but at $20 per bulb it's a a bit steep. Are you able to comment how they compare to the Feit Electric 90+ CRI bulbs sold at Costco for a few dollars a bulb?
It's tricky, though, since most LED bulbs use a single wavelength of blue LEDs which get downshifted by phosphors, even in high CRI bulbs, you can have an unnaturally large spike in the blue (often around 450nm).
I think, white LED bulbs do use a single wavelength blue LED, but they pass it through phosphors which transform it into a similar distribution of wavelength that you would find from an incandescent bulb, or sunlight. LED's are a lot better than fluorescent lighting, which does often have very dramatic peaks and gaps.
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.
Yes, white LEDs are based on blue LEDs with phosphors. But I don't think they convert all the blue light, so they're still heavy on the blue output. I'd need to see a reference to believe they have less peakiness in the spectrum than fluorescent lights.
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.
I'm in the process of building a Philips Hue-compatible light therapy LED strip that goes above my bed, and I chose 500 nm cyan LEDs due to this concern. The goal is to have the lights gradually wake me up every morning and help align my sleep cycles, as I suffer from Delayed Phase Sleep Disorder.
Figure 3[0] 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[1].
Anyone more knowledgable than me know if this setup is safe?
I'm sorry I can't help you, but after reading an article posted here about melatonin I got interested in light therapy, but commercial devices are a bit expensive.
Are you documenting your project?
Sure, it's not the most exciting project, but I might do a short writeup when I'm done.
I originally purchased these nice LED strip bars with enclosure in blue[0], but after reading this site by the manufacturers of a commercial green therapy light[1], 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.[2]
For the Hue integration, I'm using a Mesh Bee + UartSBee v5[3] with firmware from PeeVeeOne[4]. 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.
I would be very interested to see a write up of what you are doing here as I have a similar problem. Any chance you could share one if you create one? Email in my profile.
So those cyan LED's have a forward voltage drop of 3.2-3.6 volts. So you'd be looking at a 32V-36V 350ma power supply or thereabouts to hook them up in series.
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 [1]. 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.
Just tested with my power supply, and the minimum V_on seems to be about 2.7V. So if I want to drive all 10 in series, I'll need 30V+. If I had three banks in a 4,3,3 configuration, I could get away with a 12V power supply as well, which would be nice since I already have a bunch of 12V 5A wall warts.
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[0], 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.
So note the I/V curve on the diode [3]. The minimum on at 2.7V is probably going to be the "knee" voltage. Sending 1A through the led will be a higher voltage.
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 [2], or an appropriate length of copper wire [1] 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 [4].
I'm going down a similar path to build a UV light box for exposing PCB's and the like.
I remember having serious issues when I was younger with this. It's still sort of a a problem, but I've learned to cope. I'd also be interested if you documented your setup :).
Yeah, especially with these cheapo Chinese LEDs. I looked into spectrometers, but they seem pretty pricey. Maybe some sort of plastic filter that blocks the shorter wavelengths?
Yeah, you won't be able to see the intensity, but you will be able to see what components of the spectrum are there. It's also and easy way to test filters.
Yes, also if your eyes are closed when it starts, 500nm is better because more gets through the eyelid. Better if you diffuse more and spread out the light over more of the visual field.
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):
Thanks for the tips! That link is super interesting.
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.
Yes, lux depends on the viewing distance. Lumens is related to total light in all directions, and lux is "per area" (i.e. gets smaller with 1/distance^2).
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".
How long have you been using yours? I have been using one for about 3 years. Initially it worked great, but it seems the light just doesn't do it anymore and the alarm sounds are what eventually wake me up.
I wanted something that was compatible with my existing Hue system, and specifically targeted wavelengths for light therapy.
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.
Got my kitchen lighting done with these hue controlled light strips. Not entirely certain if they fulfill your need, but maybe an alternative if someone wants to replicate. They have very good CRI, which might be good/bad for your application.
https://www.sowilodesign.com
In addition to f.lux, I also use the Dark Reader Chrome extension[1], which dynamically generates dark themes for every page you visit. It seems to make a bigger difference than using f.lux.
How does the amount of blue light we see from our computers and mobile devices compare to the blue light seen from the rest of the world quantitatively? While I agree that f.lux helps in the night, I'd guess that the impact caused by f.lux to prevent the effect mentioned in the article is pretty minimal. (Obviously, I have no citations or references; just a wild guess.)
Def'ly a great relief for my eye strain - using it during the day too and keeping on by default.
One annoyance is that Chrome needs to let the address bar be darkened as well as it stands out like a neon tube when Dark Reader is on.
Thanks for sharing! I did not know about this. I use Stylus and dark themes for many sites, but this will be great for random sites.
https://add0n.com/stylus.html
Using this on an OLED screen really makes it clear that the current standard of light backgrounds and dark text is only optimal with backlit LCD panels.
2011 was a while ago, this Stack Exchange post from 2013 seems to indicate there is a possibility for macular degeneration with use of these devices, particularly if you are already at risk for the condition:
https://skeptics.stackexchange.com/questions/13891/can-blue-...
Some googling seems to indicate there were rumors of these lights potentially causing issues, and it sounds like the Chemist article may be presenting a scientific basis for that speculation.
Anyone have suggestions for kindles? A lot of the "screens" I've seen on amazon have pretty terrible reviews.
It's the one major source of nighttime blue light that I consume. I've largely given up using my phone / laptop in the dark, as I decided I'm an adult and can just leave the lights on.
Reading in bed is one of my favorite things, and it bothers my partner to leave the lights on.
What about a red light in a lamp? I use a red light to read at night. Doesn't bother my girlfriend (though she's not hugely bothered by light in general)
Combine that with an e ink non backlit kindle and you'll have no blue light.
The contrast of just your screen and focusing in the dark is likely damaging on its own; but you can add the red filter, and, if using kindle app, make the font white on black background.
But yes, as Kindles imply, reading text printed without a backlight is preferable to backlit text, so prefer lights over the backlight.
I don't quite understand. Blue light - any blue light - causes blindness? So we shouldn't look at the sky even?
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?
We have chemical receptors on our tongue and in our nose for poisons. We have neurons that detect pain. Just because we can sense it doesn't mean it's not harmful.
On the contrary in fact, I find gazing at the blue sky to be calming and enjoyable, and find it promotes diffuse thinking, which can greatly speed up problem solving.
I'd guess that the negative effects of blue light over a lifetime might only have become noticeable in modern times, with better vision correction and treatment for conditions like glaucoma and cataracts. If so, there probably hasn't been significant evolutionary pressure to dislike viewing blue light. Also, half of outdoors is blue half the time, so instinctual blue-avoidance would probably hurt survival.
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.
It says that your body's normal antioxidants prevent damage. This is only a problem for people who have low levels of alpha tocopherol, e.g. from malnourishment or aging.
The first thing to realize about any scientific paper is that it's wrong. To a very good approximation all scientific papers are wrong, until the results are replicated a couple of dozen times and failed to be replicated a few times this could well be an artifact of the methods they used.
Never make life changed based on the results of one single study.
Just speculating here, but I‘d say since eyes have evolved to also look at the sky, I’d say no. Shining a laser on cells is different from sunlight in various ways. First, laser light waves are coherent (perfectly overlapping), so their effect might amplify A LOT. The dosage (J/cm) used by the researchers also might be 100x as high as the sun‘s, for all we know. Then, there’s the thing that sunlight is a mixture of a very broad range of frequencies, from far infrared (and below, microwaves etc) up to ultraviolet (and beyond, eg X-rays, which luckily don’t arrive at the earth surface in huge doses). Again, just speculating, but near infrared has been found to have a beneficial effect on retinal diseases, so maybe it compensates for the problems blue light creates.
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.
This or something connected to it is literally ruining my last chance at life but I cannot solve it and there is always a catch. I was disabled long ago by bad surgery and left in lots of pain. My physical career was ended. I was denied social assistance and fell in every crack. Life has never been stable enough long enough to reeducate and rebuild. In suicidal desperation I posted in a few places asking for ideas. A few months back a very kind person reached out to me in response to one of my posts on social topics and offered me an opportunity, a once in a lifetime thing that can work around my issues. In the process of updating my equipment (I had been primarily using a 12yo TN/CCFL having laptop) I experienced severe eyestrain. That sent me down a path of "why" and months later I still have no answer.
Eye doctor said I was ok and found nothing to explain this. I have monovision from Lasik done 20 years ago but it's never been an issue. I tested for and ruled out, to the best of my limited ability, the common gremlins like excesive blue light (always used f.lux/redshift before) and even tried the Uvex glasses that block ALL blue light. Tried PWM free displays and no change. Lowered brightness, changed ergonomics, font rendering, drivers, filters, OLED, ambient lighting. Anything common sense or the internet has come up with doesn't work for me. I even considered it was psychosomatic given the importance of me being able to do the one last thing I could do for any conceivable work and entertainment...sit at a computer...but no tactics to deal with that help. I was thinking about making an Ask HN thread recently but my last experience with that was pretty poor and the offer came from outside of that, but I saw this relevant post today and am desperate so here I am again.
Other than some older, specific stuff like a MBP 2011 17" antiglare screen that I had to sell(panelook.com says it had an RGB backlight but some dispute that), an iPad 2 on iOS (for at least 30min anyway), and a Windows Phone Lumia 635 on Windows Phone 8.1, Any LED backlit display I look at, and ALL modern ones I have found, on any brightness, filter or setting, or OS causes tingling in my face, back of head, and neck which turns into strain/pain/headache. I can replicate it. I can soothe it with time away or using the old, half functional CCFL laptop. I have tried 8 different panels in a Thinkpad, everything Best Buy has, borrowed from people, wasted money buying on eBay and testing. No success or answers.
There is a 10yo/168+ Apple support thread with no solution (was posted here not long ago in fact and most people blamed PWM or said it wasn't a big deal). A forum called ledstrain.org where people much smarter than me have tried to drill down through drivers and dithering and other options. Many of them reduce their quality of life further by using one of the 2 expensive and limited E-Ink displays out there, or hoard specific models of old displays and GPUs and outdated OS revisions they found work for them. I just cannot live even more limited like that since everything else about my life is already shrunk and reduced and miserable. Not being able to use or function around modern LED stuff is not tenable and there is no reasonable solution even on the horizon. Everything in my life is unstable and I have to solve this to get some foundation again. I am even entertaining the idea that this is all a big cosmic prank given how perfect the timing and specificity of this issue is. So, Loki, if you are out there I surrender. You win. Please give me a break.
Do you wear glasses? Have you tried an iPad Pro with 120Hz refresh + Night Shift? How much ambient light do you have when using the computer? Is the ambient light natural or artificial? If artificial, what spectrum/type?
Sorry I updated the post as I knew I would leave some things out as I am a mental wreck and this is long and complicated. I don't wear glasses. I have monovision from Lasik done 20 years ago and am starting to have presbyopia in the distance eye but it doesn't cause issues with CCFL displays or reading or anything else. I just have aapprox 3" window 10-12" from my face where neither eye is focusing well but displays are twice that far away and the doctor said it shouldn't matter or need correction. I have tried OTC readers with the close eye lens removed to try and close the gap and it doesn't seem to change this problem.
Refresh rates and software filters don't seem to matter so far. I have this strain by a well lit window with great natural light (sometimes oddly enough direct natural light can sort of "overpower" the sharpness of the display and make it look more like E-ink and it SEEMS less bad then but hard to tell once it begins. At night I have 4x 60w incandescents in my room with no real change overall. In stores with intense LED or tube lighting it happens just as fast.
Can you be more specific about "severe eyestrain"? E.g. if there is pain, where? Eyes dry, red? Difficulty focusing? Peripheral vision? Have you had an eye exam when the strain is present? When the strain is present, what happens if you switch to reading paper? Or switch to distance vision, e.g. looking out the window? How long does it take to recover from the strain when reading or looking into the distance?
The severe issue for the last 5-6 months since trying to use LED panels has been a tingling/tightness sensation around cheeks/nose that spreads to back of head/neck/trapezius turning into pain/ache. If you clench your eyes/face and lean forward you can feel the neck/upper back tighten too and it's all that area which makes me think something is triggering eye muscles to the degree they are making me tense everything else, but I have had lots of "intuition" about this that was never correct.
Eyes have always been dry since lasik, esp when living in forced air homes, but drops and blinking don't help this. No redness that stood out to me.No peripheral vision issues. No color distortions/double vision/ weird visual stuff but mild floaters I have had for 20-25 years. It can trigger anywhere from seconds to several minutes depending on the display. I have not had an exam when it's present. No insurance and scheduling/access is not quick.
Switching to any reading/distance but the LED displays soothes it with time and I feel no symptoms reading on paper. If its flared badly and other pain/stress/tension is high it can take some hours or a night's sleep to recover. On a good day with only a few min of strain induced, an hour outside is enough. Font size, antialiasing, resolution, different distros, drivers never mattered...even tried an all AMD laptop as some think intel drivers are the culprit but it was worse than most. The old display is supposedly the worst of all specs...low res/glossy/TN/CCFL/ has PWM and not great color gamut etc. Running Xubuntu on it, but that same distro and all others hurt on the LED laptops.
I have no idea why the new displays would be different, but I did discover at one point that medication can affect eyes in surprising and wierdly lighting-device specific ways. In my case, I found that phenibut was causing a light therapy visor to hurt my eyes even on low, although strangely even fairly bright natural light did not. Even without phenibut I have trouble with the visor on high (a ReTimer that I got due to it being more greenish). Later I learned that taurine transpoters can also transport GABA and I suspect that this might have something to do with it (and that people who use high amounts of phenibut for long periods of time may be causing permanant eye damage via retinal taurine depletion). If you are taking medication and are able to try something else for a little while, there is at least a small chance that could help.
You may have tried this, but if it is muscle related then massaging your face and/or upper back might help. Not pushing, but grabbing and slowly twisting the muscles or skin. E.g. put three fingers at the bottom of your eye socket and bring your thumb up so it is an inch or a little less away from your second finger, then push your thumb up and fingers 3 and 4 down. You can repeat the same basic twisting motion over much of your face. Another one is grab skin/muscle between your thumb and two fingers and tilt towards the two fingers. Just lifting muscles (as tilting towards your thumb can sometimes do, or grab and lift) can also be quite helpful.
In the back of the neck and upper back it is easier to twist the muscle (but avoid the sides of the neck where there are fragile nerves) and additionally skin rolling can be helpful where you put two or three fingers opposite the flat side of your thumb, grab a small amount of skin (and potentially muscle too, although your focus should be on the skin) and then walk your thumb forward with your fingers, such that there is a raised area that moves in front of your thumb. If it feels "crunchy" at all or feels like it is sticking to the muscle (that you can't lift the skin as easily as elsewhere), go over it again until it doesn't, although not necessarily all at once since it can be exceptionally painful in some cases (in that case, just do a little each day and it should eventually not be painful). The twisting can usually be done in a way that affects just the skin or the muscle as well and both can be helpful.
Those three techniques (twisting or lifting muscles and twisting or rolling skin) are IMO the most useful ones anywhere on the body you can do them (also don't get too close to most joints), but just applying pressure to muscles doesn't really help in my experience. Lifting muscles on your own back is hard and not necessarily worth aiming for. For the face another good technique if you can is to put down your middle three fingers and keep them in one spot on your skin while moving your hand rapidly within a quarter inch or so of that spot.
The muscle/skin adherence particularly tends to happen on legs, most of all upper legs but often both, although the upper back/shoulder area is another area it frequently happens. If you see a massage therapist, look for Shiatsu, Tui-Na, or (not exclusively stretching focused) Thai massage since those styles are more focused on this kind of thing. But there may be quite a bit you can do yourself (depending on your other issues) that can be helpful. I guess it is unlikely to fix the real issue here but might at least help you recover faster.
"Later I learned that taurine transpoters can also transport GABA and I suspect that this might have something to do with it"
Can you clarify this? Phenibut affects GABA but above you said, taurine transporters can also transport GABA so I am not sure what you mean. Are you saying that Phenibut might hijack the taurine transporters so they cannot be used for Taurine? I have taken Zolpidem (which affects GABA) for sleep off and on for long periods but I am pretty sure I had this strain even when off it for 6 months or so so not super hopeful. Do I need to supplement Taurine then or is there some test for it in the retina you can have done? If it's permanent as you say that's not hopeful.
However once again, and I know you said it was weirdly spcific, but since this only happens on LED backlit displays I find it hard to believe it's something like that since that should affect other visual things.
Sorry, I didn't mean to imply that I thought permanant damage was likely in your case (unless you happened to be taking a lot of Phenibut over a long period of time), just that it is possible that some medication could somehow be causing your problem.
At least GABA itself is transported by the taurine transporters and if you have enough GABA (as far as I know this has only been observed with vigabatrin use or rare genetic GABA metabolism disorders) then the retina will not get enough taurine and peripheral vision will suffer permanant damage that can only be detected with a special test until it gets quite bad. Taurine supplementation does prevent damage in that case.
Phenibut might possibly have the taurine transporter issue since (unlike Zolpidem) it is considered a GABA analog plus some people take quite a lot of it and even the lowest doses are quite a bit higher than the higest Zolpidem dose. Baclofen is similar to Phenibut but used in much lower quantities so it also seems unlikely to cause that trouble (and it actually doesn't cause my eyes to hurt). And I could be completely wrong about Phenibut having that particular issue, all I really know is that it makes my eyes hurt when I use the light therapy visor. Actually, I just remembered that taurine itself causes my eyes to hurt in the same way, so while it could still potentially be taurine transporter related it at least isn't a lack of taurine for my particular issue (sorry, I am also disabled due to sleep issues in my case and either that or some additional unknown issue affects my memory).
I see that Zolpidem does have multiple common eye related side effects, so somehow it can negatively affect the eyes. If you haven't been taking medication the whole time you have noticed the problem then that should be enough to conclude that it isn't medication related. Or if you are taking something else (like pain medication) but can't fairly easily change to something with a different mechanism of action then I don't think it is likely enough to be worth too much trouble (but keep the possibility in mind if you are ever in a position to test it).
For me it was even more specific, just the one particular LED light that caused the trouble, not my computer screen (which is older but I just checked and it is LED backlight) or brighter natural light, or anything else. I would have also thought it should affect other visual things but somehow it didn't (although in my case maybe it is somehow connected to the LED being so close to my eyes).
Have you tried an external LCD monitor that is big enough for you to increase the viewing distance to about 40"/100cm? As a simple experiment, move your current laptop further away, increase the font size and see if the time-to-eyestrain gets longer.
There are gaming monitors which have faster refresh rates.
Dry eyes need to be addressed, as the tear film contributes to clear vision. You can use a "sipper" bottle of water to keep your upper respiratory track moistened. Yawning can trigger lubrication of the eyes, if you are drinking enough water.
I have adjusted distance and font size and every other display parameter I can with no effect. refresh rates seem irrelevant. I use eye drops when needed but have had this dryness issue since lasik surgery in 2000. It's not so bad in non-forced air homes where it's not as dried out all the time but right now I am in one. I drink a lot of water. I don't have EMF sensitivity that I know of and again this only happens with LED displays so far.
You've probably seen this LED vs CCFL monitor thread, it mentioned that CCFL screens are matte, is there any chance that your LED screens have a lot of reflections from objects/lighting behind you? https://superuser.com/questions/149362/is-an-led-monitor-bet...
I've researched these kind of symptoms, and the only common cause I could find on the internet from the few people that complained about this was that it was caused by an infection in the head/neck area. One person had an infected wisdom tooth, another one some problem with his neck.
Taking some Vitamin D may help (stay under the 4000 UI/day tolerable upper limit). There's a forum where people with similar issues used gather at http://bcomputermonitorpain.runboard.com/
As far as computer monitors go, you could either use an old CRT monitor, or try a e-ink monitor such as the Dasung Paperlike, or a modded Android e-ink tablet.
> reduce their quality of life further by using one of the 2 expensive and limited E-Ink displays out there
Could you elaborate on above? I did not understand the logic behind the sentence. E-Ink displays by themselves do not generate any light as they don't have any backlight or light emitter behind the display. That's why they work in bright sunlight. Some products with E-Ink displays have frontlights for night time reading. Is that what you are referring to? If so, given this article, just turning off the frontlight and using non-blue light sources for lighting is sufficient to avoid this, right?
I was stating that having to use the available E-ink displays is a reduction in quality of life because they are small (13"), expensive (~1000usd), and limited in function and performance which makes most web activities aggravating due to lag and ghosting. They aren't a solution, but just a more difficult workaround that shrinks life even more in my case.
I use Night Shift. I'm able to fall asleep minutes after closing my laptop and laying down. For me it's more about comfort than sleep. The blue light is much too bright late at night. My computer no longer hurts my eyes when I stay up late working on cool things.
I've been using F.lux for over seven years. Advantages…
- 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)
While the color temperature is adjustable, I've found (anecdotally) that the warmest setting on Night shift is still quite a bit more blue compared to the max warmness on F.lux.
(Tested on iMac and MacBook Air, may be different for other screens)
I prefer f.lux, with the exception of fullscreen video, specifically YouTube on Chrome, where certain colors "break through" the filtering and appear bright white. Not sure how it works, but it's the only thing Night Shift seems to do better. If f.lux fixed it I'd be back in a heartbeat
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[ 3.1 ms ] story [ 103 ms ] threadhttps://news.ycombinator.com/newsguidelines.html
edit: the way I remember it is that like any type of radiation, anything that goes into your body stays there pretty much until your death, the only way to keep your "uv capital" in good shape is to be proactive about it, cant do anything retroactively. This is why about 1/3rd of Australians will develop some form of skin cancer in their lifetime.
If you Google this subject there are several websites where people went out and bought cheap an expensive sunglasses and had them tested and reached the same conclusion: UV protection does not justify expensive Raybans.
I have never been comfortable in their presence as my eyes begin to fatigue and I experience discomfort. YMMV.
Lights used in something like a tanning bed, can obviously burn your skin and also damage your eyes that is why people should wear eye protection, or do the healthy thing and not tan at all.
This was one of several reasons I quit that lab. Since then I've avoided academic labs that have UV lights or lasers because I don't trust that the students follow safety procedures at all.
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.
Examples of a GB-R LED backlit display include the NEC PA302W, so they aren't common.
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)
https://www.zeiss.com/vision-care/en_us/products/coating-col...
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 [0].
[0]: http://twin.sci-hub.tw/6979/4112e16f7195f7f33cd3e861c6345df0...
http://www.nature.com/articles/s41598-018-28254-8
http://www.nature.com/articles/s41598-018-28254-8.pdf
Start a pension.
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?
From what i heard this is also why sunglasses that don't block UV light are worse than not having sunglasses at all.
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.
[0] https://twilight.urbandroid.org
https://www.techrepublic.com/article/pro-tip-dim-your-ios-sc...
It's not the easiest mode to find, but works.
[0] https://play.google.com/store/apps/details?id=com.vitocassis...
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?
Nope
> 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?
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.
Somewhat constricted. They're still more open that if they were in a fully lit environment, even more so in the sun.
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.
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 think some ultra-bright headlights are actually slightly blue.
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 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.
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.
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.
[1] https://play.google.com/store/apps/details?id=com.haxor
[0] https://www.home-assistant.io/components/switch.flux/
If I don't dial mine way down it's very uncomfortable
But never going outside would mess with circadian rhythm.
But isn't this bad with other consequences? I thought the lack of blue/violet light was the cause of myopia? https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5233810/
The cynic in me wonders if the researchers have any ties to VSP.
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.
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.
https://en.wikipedia.org/wiki/Color_temperature#Categorizing...
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.
Figure 3[0] 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[1].
Anyone more knowledgable than me know if this setup is safe?
[0]: https://www.nature.com/articles/s41598-018-28254-8/figures/3 [1]: https://en.wikipedia.org/wiki/Melanopsin#Effects_on_circadia...
I originally purchased these nice LED strip bars with enclosure in blue[0], but after reading this site by the manufacturers of a commercial green therapy light[1], 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.[2]
For the Hue integration, I'm using a Mesh Bee + UartSBee v5[3] with firmware from PeeVeeOne[4]. 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.
[0]: https://www.ebay.com/itm/50CM-U-Aluminium-shell-DC-12V-36-SM...
[1]: http://www.sunnexbiotech.com/blue%20vs%20green%20light.html
[2]: https://www.aliexpress.com/item/10-pcs-3W-Turquoise-Cyan-LED...
[3a]: https://www.seeedstudio.com/Mesh-Bee-Open-Source-Zigbee-Pro-...
[3b]: https://www.seeedstudio.com/UartSBee-V5-p-1752.html
[4]: https://peeveeone.com/?page_id=252
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 [1]. 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.
[1] https://www.aliexpress.com/store/product/10PCS-A58B-1W-LED-D...
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[0], 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.
[0]: http://www.xlsemi.com/datasheet/XL4001%20datasheet.pdf
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 [2], or an appropriate length of copper wire [1] 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 [4].
I'm going down a similar path to build a UV light box for exposing PCB's and the like.
Best of luck!
[1] http://hyperphysics.phy-astr.gsu.edu/hbase/Tables/wirega.htm...
[2] https://www.mouser.com/ProductDetail/Bourns/CRM2512-FX-R150E...
[3] https://www.electronics-tutorials.ws/blog/i-v-characteristic...
[4] https://circuitdigest.com/microcontroller-projects/raspberry...
I mean the delayed phase sleep disorder. Will talk to the doc about it.
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.
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):
https://fluxometer.com/rainbow/#!id=Light%20Therapy/ReTimer
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 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.
1. https://chrome.google.com/webstore/detail/dark-reader/eimadp...
https://www.usa.philips.com/c-p/HF3429_60/golite-blu-energy-...
2011 was a while ago, this Stack Exchange post from 2013 seems to indicate there is a possibility for macular degeneration with use of these devices, particularly if you are already at risk for the condition: https://skeptics.stackexchange.com/questions/13891/can-blue-...
Some googling seems to indicate there were rumors of these lights potentially causing issues, and it sounds like the Chemist article may be presenting a scientific basis for that speculation.
Turned off my light for now.
It's the one major source of nighttime blue light that I consume. I've largely given up using my phone / laptop in the dark, as I decided I'm an adult and can just leave the lights on.
Reading in bed is one of my favorite things, and it bothers my partner to leave the lights on.
Combine that with an e ink non backlit kindle and you'll have no blue light.
But yes, as Kindles imply, reading text printed without a backlight is preferable to backlit text, so prefer lights over the backlight.
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?
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.
Source: https://en.wikipedia.org/wiki/Ozone
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.
Few things are "automatically" bad. Over time though, effects are cummulative, and there are also breaking points for lots of bad stuff.
Never make life changed based on the results of one single study.
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.
Eye doctor said I was ok and found nothing to explain this. I have monovision from Lasik done 20 years ago but it's never been an issue. I tested for and ruled out, to the best of my limited ability, the common gremlins like excesive blue light (always used f.lux/redshift before) and even tried the Uvex glasses that block ALL blue light. Tried PWM free displays and no change. Lowered brightness, changed ergonomics, font rendering, drivers, filters, OLED, ambient lighting. Anything common sense or the internet has come up with doesn't work for me. I even considered it was psychosomatic given the importance of me being able to do the one last thing I could do for any conceivable work and entertainment...sit at a computer...but no tactics to deal with that help. I was thinking about making an Ask HN thread recently but my last experience with that was pretty poor and the offer came from outside of that, but I saw this relevant post today and am desperate so here I am again.
Other than some older, specific stuff like a MBP 2011 17" antiglare screen that I had to sell(panelook.com says it had an RGB backlight but some dispute that), an iPad 2 on iOS (for at least 30min anyway), and a Windows Phone Lumia 635 on Windows Phone 8.1, Any LED backlit display I look at, and ALL modern ones I have found, on any brightness, filter or setting, or OS causes tingling in my face, back of head, and neck which turns into strain/pain/headache. I can replicate it. I can soothe it with time away or using the old, half functional CCFL laptop. I have tried 8 different panels in a Thinkpad, everything Best Buy has, borrowed from people, wasted money buying on eBay and testing. No success or answers.
There is a 10yo/168+ Apple support thread with no solution (was posted here not long ago in fact and most people blamed PWM or said it wasn't a big deal). A forum called ledstrain.org where people much smarter than me have tried to drill down through drivers and dithering and other options. Many of them reduce their quality of life further by using one of the 2 expensive and limited E-Ink displays out there, or hoard specific models of old displays and GPUs and outdated OS revisions they found work for them. I just cannot live even more limited like that since everything else about my life is already shrunk and reduced and miserable. Not being able to use or function around modern LED stuff is not tenable and there is no reasonable solution even on the horizon. Everything in my life is unstable and I have to solve this to get some foundation again. I am even entertaining the idea that this is all a big cosmic prank given how perfect the timing and specificity of this issue is. So, Loki, if you are out there I surrender. You win. Please give me a break.
Refresh rates and software filters don't seem to matter so far. I have this strain by a well lit window with great natural light (sometimes oddly enough direct natural light can sort of "overpower" the sharpness of the display and make it look more like E-ink and it SEEMS less bad then but hard to tell once it begins. At night I have 4x 60w incandescents in my room with no real change overall. In stores with intense LED or tube lighting it happens just as fast.
Eyes have always been dry since lasik, esp when living in forced air homes, but drops and blinking don't help this. No redness that stood out to me.No peripheral vision issues. No color distortions/double vision/ weird visual stuff but mild floaters I have had for 20-25 years. It can trigger anywhere from seconds to several minutes depending on the display. I have not had an exam when it's present. No insurance and scheduling/access is not quick.
Switching to any reading/distance but the LED displays soothes it with time and I feel no symptoms reading on paper. If its flared badly and other pain/stress/tension is high it can take some hours or a night's sleep to recover. On a good day with only a few min of strain induced, an hour outside is enough. Font size, antialiasing, resolution, different distros, drivers never mattered...even tried an all AMD laptop as some think intel drivers are the culprit but it was worse than most. The old display is supposedly the worst of all specs...low res/glossy/TN/CCFL/ has PWM and not great color gamut etc. Running Xubuntu on it, but that same distro and all others hurt on the LED laptops.
You may have tried this, but if it is muscle related then massaging your face and/or upper back might help. Not pushing, but grabbing and slowly twisting the muscles or skin. E.g. put three fingers at the bottom of your eye socket and bring your thumb up so it is an inch or a little less away from your second finger, then push your thumb up and fingers 3 and 4 down. You can repeat the same basic twisting motion over much of your face. Another one is grab skin/muscle between your thumb and two fingers and tilt towards the two fingers. Just lifting muscles (as tilting towards your thumb can sometimes do, or grab and lift) can also be quite helpful.
In the back of the neck and upper back it is easier to twist the muscle (but avoid the sides of the neck where there are fragile nerves) and additionally skin rolling can be helpful where you put two or three fingers opposite the flat side of your thumb, grab a small amount of skin (and potentially muscle too, although your focus should be on the skin) and then walk your thumb forward with your fingers, such that there is a raised area that moves in front of your thumb. If it feels "crunchy" at all or feels like it is sticking to the muscle (that you can't lift the skin as easily as elsewhere), go over it again until it doesn't, although not necessarily all at once since it can be exceptionally painful in some cases (in that case, just do a little each day and it should eventually not be painful). The twisting can usually be done in a way that affects just the skin or the muscle as well and both can be helpful.
Those three techniques (twisting or lifting muscles and twisting or rolling skin) are IMO the most useful ones anywhere on the body you can do them (also don't get too close to most joints), but just applying pressure to muscles doesn't really help in my experience. Lifting muscles on your own back is hard and not necessarily worth aiming for. For the face another good technique if you can is to put down your middle three fingers and keep them in one spot on your skin while moving your hand rapidly within a quarter inch or so of that spot.
The muscle/skin adherence particularly tends to happen on legs, most of all upper legs but often both, although the upper back/shoulder area is another area it frequently happens. If you see a massage therapist, look for Shiatsu, Tui-Na, or (not exclusively stretching focused) Thai massage since those styles are more focused on this kind of thing. But there may be quite a bit you can do yourself (depending on your other issues) that can be helpful. I guess it is unlikely to fix the real issue here but might at least help you recover faster.
Can you clarify this? Phenibut affects GABA but above you said, taurine transporters can also transport GABA so I am not sure what you mean. Are you saying that Phenibut might hijack the taurine transporters so they cannot be used for Taurine? I have taken Zolpidem (which affects GABA) for sleep off and on for long periods but I am pretty sure I had this strain even when off it for 6 months or so so not super hopeful. Do I need to supplement Taurine then or is there some test for it in the retina you can have done? If it's permanent as you say that's not hopeful.
However once again, and I know you said it was weirdly spcific, but since this only happens on LED backlit displays I find it hard to believe it's something like that since that should affect other visual things.
At least GABA itself is transported by the taurine transporters and if you have enough GABA (as far as I know this has only been observed with vigabatrin use or rare genetic GABA metabolism disorders) then the retina will not get enough taurine and peripheral vision will suffer permanant damage that can only be detected with a special test until it gets quite bad. Taurine supplementation does prevent damage in that case.
Phenibut might possibly have the taurine transporter issue since (unlike Zolpidem) it is considered a GABA analog plus some people take quite a lot of it and even the lowest doses are quite a bit higher than the higest Zolpidem dose. Baclofen is similar to Phenibut but used in much lower quantities so it also seems unlikely to cause that trouble (and it actually doesn't cause my eyes to hurt). And I could be completely wrong about Phenibut having that particular issue, all I really know is that it makes my eyes hurt when I use the light therapy visor. Actually, I just remembered that taurine itself causes my eyes to hurt in the same way, so while it could still potentially be taurine transporter related it at least isn't a lack of taurine for my particular issue (sorry, I am also disabled due to sleep issues in my case and either that or some additional unknown issue affects my memory).
I see that Zolpidem does have multiple common eye related side effects, so somehow it can negatively affect the eyes. If you haven't been taking medication the whole time you have noticed the problem then that should be enough to conclude that it isn't medication related. Or if you are taking something else (like pain medication) but can't fairly easily change to something with a different mechanism of action then I don't think it is likely enough to be worth too much trouble (but keep the possibility in mind if you are ever in a position to test it).
For me it was even more specific, just the one particular LED light that caused the trouble, not my computer screen (which is older but I just checked and it is LED backlight) or brighter natural light, or anything else. I would have also thought it should affect other visual things but somehow it didn't (although in my case maybe it is somehow connected to the LED being so close to my eyes).
There are gaming monitors which have faster refresh rates.
Dry eyes need to be addressed, as the tear film contributes to clear vision. You can use a "sipper" bottle of water to keep your upper respiratory track moistened. Yawning can trigger lubrication of the eyes, if you are drinking enough water.
Do you have EMF sensitivity?
Dell U2711 monitor has a CCFL backlight, is available on eBay, http://www.tftcentral.co.uk/reviews/dell_u2711.htm
You've probably seen this LED vs CCFL monitor thread, it mentioned that CCFL screens are matte, is there any chance that your LED screens have a lot of reflections from objects/lighting behind you? https://superuser.com/questions/149362/is-an-led-monitor-bet...
This 2018 article summarizes display technologies for backlighting and phosphors for color accuracy, you can see a range of color spectra, https://pcmonitors.info/articles/the-evolution-of-led-backli...
This site has articles on eye sensitivity to light color, https://glarminy.com/2016/04/11/are-your-eyes-sensitive-to-l..., they sell a $20 kit with 8 filters that mimic the spectrogram of various commercial glasses for blue blocking or migraine relief, it's a cheap way to test how your eyes react to different filters+devices, https://glarminy.com/blue-filter-tester/
Taking some Vitamin D may help (stay under the 4000 UI/day tolerable upper limit). There's a forum where people with similar issues used gather at http://bcomputermonitorpain.runboard.com/
As far as computer monitors go, you could either use an old CRT monitor, or try a e-ink monitor such as the Dasung Paperlike, or a modded Android e-ink tablet.
Could you elaborate on above? I did not understand the logic behind the sentence. E-Ink displays by themselves do not generate any light as they don't have any backlight or light emitter behind the display. That's why they work in bright sunlight. Some products with E-Ink displays have frontlights for night time reading. Is that what you are referring to? If so, given this article, just turning off the frontlight and using non-blue light sources for lighting is sufficient to avoid this, right?
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.
https://9to5mac.com/2017/03/28/flux-developer-says-apples-ne...
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)