Blue light and the retina



  • Blue light emissions from computer and cell phone screens have been proven to cause damage to retinal cells over time. I am wondering to what extent does the f.lux app protect against blue light? For example, certain amber tinted lenses will reduce blue light transmission to the eye by about 30%.

    F.lux is a very cool app. Thanks!


  • f.lux team

    The blue light you see from staring at full brightness computer and cell phone screens is insignificant compared to what you see from spending 5 minutes outside on a sunny day. Retinal damage in otherwise normal eyes is proven to be caused by small, extremely bright blue lights (if you are looking at lasers or bright GaN LEDs without eye protection for example).

    More research is certainly needed to understand more about what happens when we stare at screens for hours into the night, but generally speaking blue light during the day is fine to see, healthy in fact. It helps set our light dark cycles.

    All that said - we posted an online measurement project at https://fluxometer.com/rainbow/ - it's pretty interesting what different products do. Some do a lot, and some don't do very much at all.



  • @lorna @elisadelina Here's my favorite that you've added (It's in my firefox ... most visited or something when I open a new tab):

    https://fluxometer.com/rainbow/#!id=Outdoors/2PM LA sky



  • Hmm, not sure I'd agree that it's quite so insignificant and "fine"...

    The American Optometric Association says:

    Chronic exposure to shorter-wavelength visible light (blue and violet light) may also be harmful to the retina. Many digital devices emit this shorter-wavelength visible light.

    Blue light is part of the visible light spectrum. The sun emits blue light, as do artificial light sources, such as LEDs, computers and smartphones. Some types of blue light can be beneficial, helping us regulate our bodies' internal biological clocks.

    However, blue-violet light can be harmful to the eyes, specifically the retina. It is a risk factor for the onset of age-related macular degeneration, a deterioration of the part of the retina responsible for sharp, central vision.

    A recent study found that Americans spend almost 2 ½ hours on their tablets and smartphones every day. In addition, most offices and stores use fluorescent light bulbs, and LED lights are becoming increasingly popular.

    Lenses that absorb harmful blue light but allow beneficial blue light through your lenses are entering the marketplace. You could also apply a special clear coating to traditional lenses to enhance their ability to block these harmful rays while you use computers and smartphones.

    We're talking about long-term exposure, over a lifetime, and problems that don't show up until you're in your 70s or so. If you don't make it that far, then all the effort you put into things like quitting smoking, wearing sunscreen and sunglasses, protecting your ears from loud noises, not eating too much sugar, salt, and fat, and getting enough sleep, will have been a waste of time. But if you do, you'll be very glad you did. Being old is kind of annoying, but tolerable. Being old, sick, blind, deaf, and having dementia, not so much.

    Yes, f.lux can significantly reduce the harmful blue wavelengths from computer monitors, similar to wearing amber-tinted lenses. The "special clear coating" mentioned above is more fine-tuned though. It can block the harmful blue-violet wavelengths, while still letting through the blue-green ones that help synchronize circadian rhythms. F.lux can only control the overall brightness of the blue pixels (which emit blue-violet, blue, and blue-green), it can't be that selective about the wavelengths.

    You can reduce blue light from a monitor by 30%, just by turning down the brightness by 30%. F.lux basically works by only turning down the brightness of the blue pixels, while leaving the green and red ones the same.

    Whether 30% is adequate, or actually unnecessary, is really difficult to say. It depends how much time you spend on the computer, and all the other exposure you get over many decades. Better safe than sorry, I suppose.


  • f.lux team

    @Elhem-Enohpi First, it's incorrect to say that f.lux leaves green pixels the same. f.lux removes a significant amount of green light (which is also melanopically stimulating and alerting) in addition to blue.

    Second: light from smartphones and computer screens is specifically what I'm referring to, and while these light sources are proven to affect sleep they have not been proven to cause damage to the retina in normal healthy eyes. There are many issues from screen use, and effects of blue light is just one in a very long list of problems that could come with long term use.

    Again, I'll say that simply being outside will expose you to much more "damaging" blue light than an entire day at the computer. But there are other factors and certainly a big one is the fact that the sun sets while computers shine on all night long.

    It's beneficial to many to block UV light and most glasses will do a fine job of this (remember, LED monitors don't emit UV light). But when you hear about visible blue light causing retinal damage, it's due to an extremely bright light source, one that you'll never normally see unless you work with LEDs, lasers or some types of optical or specialized medical equipment. People who work with this type of equipment must wear special eye protection to protect against this light. In these cases eyeglass coatings will do absolutely nothing to protect you.

    Most eyeglass coatings block between 5 and 10% of the high energy visible blue light spectrum. f.lux defaults block 95%.


  • f.lux team

    This is a nice overview on the hazards of blue light from two extremely well-informed individuals, for anyone interested in reading a bit more: http://www.ledsmagazine.com/articles/print/volume-12/issue-4/features/q-a/questions-abound-about-whether-a-blue-light-hazard-exists.html

    And for the fun of it, here's IEC62471:2006, "Blue Light Hazard," compared against a typical UV coating:
    https://fluxometer.com/rainbow/#!id=filter/UV eyeglasses&action=BlueLightHazard


  • f.lux team

    Agreed - the marketing here is totally out of control.

    Most eyewear coatings claiming to "block" harmful blue light actually block about 10% of it. The best ones block 20%. The super-yellow ones block 30%. None of this matters.

    If you want to have a noticeable effect on retinal health you'd block 90% or more, which f.lux does.

    But in reality, screens aren't really that bright - in power terms you'd need more than 12 hours exposure of the brightest screen to equal 1 minute outdoors in the sun.



  • @herf said:

    But in reality, screens aren't really that bright - in power terms you'd need more than 12 hours exposure of the brightest screen to equal 1 minute outdoors in the sun.

    Roofs need to let in light without reducing the strength of itself somehow, yes skylights, but those can be expensive and aren't really mainstream at all.

    Sunlight / outdoor readable monitors need to be a LOT less expensive and much more common. I've talked about it a bit, but I still can't find a reasonably priced LED monitor that puts out around 1,000+ nits. The closest I've found is a nice Samsung display that does about 1500 nits for about the same price in USD.



  • @lorna I wrote that f.lux "basically" works that way, but I probably over-simplified it, sorry. F.lux is of course more sophisticated than that in controlling the colour temperature.

    But I've noticed that people often think that f.lux is able to apply an arbitrary spectrum filter, adjusting specific wavelengths. What I was trying to get across is that f.lux can't attenuate eg. 440 nm light, while still passing 480 nm light, as could be done with an optical filter; it can only adjust the relative brightness of the red, green, and blue pixel elements.

    People working in the optometry industry vs. the lighting industry might be expected to have rather different opinions on whether LEDs contribute to age-related macular degeneration (AMD). Having "not been proven to cause damage to the retina" isn't the same as having been proven to have no long-term effect.

    I think this 2004 paper says it reasonably well:

    Evidence from animal studies confirms blue light's damaging potential but the results are not directly applicable to macular degeneration in humans. Studies of human macular pigment density and the risk of AMD progression following cataract surgery lend further weight to the hypothesis that blue light exposure has a role in the pathogenesis of AMD but the epidemiological evidence is equivocal. On balance the evidences suggests but does not yet confirm that blue light is a risk factor for AMD.

    There does seem to be a lot of fear, uncertainty, and doubt out there, with sensational articles implying that white LEDs and screens produce some kind of harmful radiation that's different from what you get from ordinary sunlight. That is of course nonsense.

    But the argument that computer screens aren't nearly as bright as the sun, and therefore pose no problem, isn't so convincing. Five hours a day of summer sunlight exposure as a teengager increases the risk of AMD later in life. What about the office worker in front of a computer eight hours a day for forty years?

    That person may have less risk than someone who works outdoors, but it's not unlikely that both would benefit from eye protection. The above paper says AMD "is a major health problem in the developed world accounting for approximately half of all blind registrations", and there are no viable treatment options.

    The fact that the IEC62471:2006 "Blue Light Hazard" spectrum exists, suggests that it's a concern. The recomended "safe" exposure levels are based on short-term acute effects, in those people working with lasers and so on. They say nothing about chronic long-term exposure. The guide for implementing the EC Directive 2006/25/EC says:

    Most exposure limits are based on studies of thresholds for acute effects, and derived from statistical consideration of these thresholds. [...] Chronic effects often do not have a threshold below which they will not occur. As such, the risk of these effects occurring cannot be reduced to zero.

    Typical UV coatings aren't designed to protect against retinal damage. A better example would be:
    https://fluxometer.com/rainbow/#!id=filter/GUNNAR PPK&action=BlueLightHazard
    ...which appears to reduce the potentially retina-damaging < 450 nm light by 50% or more, while having relatively little effect on the ~490 nm melanopic range.

    @herf I can't quite imagine where you'd be getting those numbers from, 30% "doesn't matter", and "If you want to have a noticeable effect on retinal health you'd block 90% or more". We know that smoking five cigarettes a day for a year or two probably won't have much effect on long-term health. A pack a day for thirty years certainly will. With blue light, we just don't have those kinds of numbers yet.

    I'm not suggesting people need to go around wearing amber-coloured glasses all day, I'm sure that's a bad idea. But AMD is a serious problem for a large proportion of the elderly population, and there's evidence, if not conclusive, that chronic exposure to ~440 nm light over a lifetime is a major factor. Taking reasonable measures to limit that would seem to be prudent, along with getting enough sleep, eating vegetables, and flossing.

    As the science matures, I hope we'll see industry taking steps to help people reduce the risks of AMD. For example, computer screen manufacturers could develop better pigmentation for the blue pixel filters. Eyeware manufacturers could create more effective protective lens designs. The issue is not something to panic about, but definitely worth keeping an eye on...


  • f.lux team

    Elhem, I value your comments and your participation in the forum, but I don't like the direction this conversation is taking.

    1. You're not "probably" oversimplifying it, you're posting incorrect information. What you are describing an optical notch filter, which is incredibly expensive. This is not how eyeglass coatings work.

    2. We work closely with people in both the optometry and lighting industries, and we're not talking about opinion, we are talking about proven facts and measurable, repeatable data. I see plenty of incorrect information in both of these industries. Their sales numbers often depend on marketing materials that consistently mislead, frighten, and confuse consumers. For example, the OP also posted wrong information: "Blue light emissions from computer and cell phone screens have been proven to cause damage to retinal cells over time." This is not a true statement. Might they cause harm? Possibly. Should people use common sense? Of course. But it is our responsibility to talk about what is known, and we should not spread fear / uncertainty / doubt when we can talk about facts instead.

    3. You are confusing the IEC62471:2006 blue light hazard spectrum with the spectrum related to AMD - they are not the same thing. Blue Light Hazard exists to measure something that is a specific concern, to a specific population working with potentially dangerous equipment.

    4. There are hundreds of studies about this topic, many with unclear results, so please let's not have a squirtgun fight with cherrypicked lines from paywalled abstracts.

    5. Everyone basically agrees that blue light can cause damage to older retinas (this appears to be due to blue light's reaction with the pigment lipofuscin, which is found in damaged, older tissues). Some studies show that there is not a risk factor with light seen in younger eyes but related to light seen later in life. But, the lens yellows with age, and by age 60 it filters out more blue light than Gunnar's glasses.

    6. People at risk for AMD (like me - I have a vested interest in this particular topic) should be getting information about this from ophthalmologists, not optometrists, and not internet forums.

    I know Mike has some things he wants to say, so I will stop here.


  • f.lux team

    I agree with you that we have no evidence for long-term effects, except for studies on time spent outdoors (Boulder Dam). And the risks are not evenly distributed: people with aphakic eyes should take special precautions, and those with diagnosed AMD should make every attempt to keep it from progressing.

    But what we can do is compare screens to known lights and known standards.

    1. Computer screens are designed to emulate paper viewed under bright office lighting, and compared to fluorescent light reflected by paper, it is extremely hard to argue that LED screens cause more harm. The typical office fluorescent produces "blue" at 437nm, and the typical backlit screen produces "blue" at 455nm, and it produces very little energy below 430nm. The higher-energy from a fluorescent has a bigger effect in the retinal harm studies. Also, turning down the blue primary makes almost a perfect low-pass 480nm filter. Moving the blue primary from 450nm to 460nm like OLED might have a small effect, but there is no magic in optical filters in this case.

    2. Light outdoors is dramatically brighter (even with sunglasses on). By "dramatically" I do not mean 30% brighter, I mean 100x brighter.

    3. You are making a common mistake, in guessing that "effect sizes" are proportional to luminance. So most people guess, well, if I turn this light down by 20%, I will have 20% less sleep disruption/retinal harm/sunburn/etc. But this is a serious mistake. The thing to understand is that the effect sizes for all these things are in fact logarithmic and so you must make a 10x change in the input to have a reasonable effect on the output. If you had to say, instead, "these glasses reduce the harmful effect by 0.05%" you'd sound silly, so people should not make hyperbolic claims about filters that reduce a certain wavelength by 10%.

    4. I have read IEC62471, and it specifies testing a light source at 500lux, to estimate how much harm will be caused. There is essentially no viewing distance for a monitor at which you can achieve 500 lux. This standard says LED displays are "exempt" from light-based retinal harm.

    If you move your monitor away by 1", or dim it by one tick, you'll make a bigger difference in the physics than most filters on the market, so I think these filters are extremely silly, and I think the marketing should not be allowed.

    If there is an effect due to light at these irradiance levels, the mechanism will be due to exposure after dark and deep into the night, because no "normal" exposure is reasonable to cause retinal harm.

    I stand by my assertion that removing 90-99% of the light should be a target for anyone seriously trying to offer a "fix" for these "problems" (both of which are unproven).

    All else is snake oil, and we should call it that.


  • f.lux team

    Here is a summary by one of the actual experts on retinal harm (Dirk van Norren). The "outlier" data for rodents around 500nm is for albino mice, and so for everyone else, what this graph says is "don't stare directly at the sun". Much of the current standards and eyewear claims are based in the Ham 1976 data, I remember.

    Just to be clear, retinal harm is indicated here at doses "smaller than" 100 J/cm2.

    Apple's 27" Cinema Display makes 0.0000125 W/cm2, so a 12-hour exposure of that is 0.54 J/cm2. But we do not have a way to even guess at why seeing "normal luminance" sources would have an effect.

    You can never say never, but you can say the evidence is extremely uncompelling.

    alt text


  • f.lux team

    And at least the UK is finally cracking down on bogus advertising:

    http://www.dailymail.co.uk/news/article-3292789/Boots-glasses-claim-misleading.html



  • Lorna, I'm just an amateur, and here to learn. All I know is what I've read online. A year ago, I didn't even know there were any issues with blue light at all. If I've misunderstood something, I'm happy to be corrected! And if I post something that disagrees with what you've said, I don't mean to challenge you, I'm really just asking a question and hoping to learn from the discussion.

    As I'm getting on in years, and facing some health issues, I wish I'd done some things differently when I was younger, and had more information. Wikipedia makes everyone an "armchair expert", which can be annoying, but does have value. I'm hoping to learn to take better care of my health, and maybe help others a little to understand things, along the way. I'm pretty sure it's clear to everyone in these forums that you and Michael are the only real experts here...

    @lorna said:

    1. You're not "probably" oversimplifying it, you're posting incorrect information. What you are describing an optical notch filter, which is incredibly expensive. This is not how eyeglass coatings work.

    I was trying to describe a longpass filter, something that passes only wavelengths longer than eg. 460 nm:

    alt text
    Rosco creates all kinds of different curve profiles with their filters, by using different combinations of dye. My point was about what seems to be a common misperception among some users that f.lux (or any software) is able to apply a filter attenuation curve of any arbitrary shape, and control specific wavelengths across the spectrum; whereas actually it only has control over the three broad RGB filter channels. It can't reduce the 440 nm light more than it reduces 480 nm light, while a physical filter or lens coating could.

    Whether that would have any actual value or not, even with 100% attenuation, I admit that I don't know. I'm not sure that anyone really does. The AOA states in the context of LED lighting, "blue-violet light can be harmful to the eyes, specifically the retina. It is a risk factor for the onset of age-related macular degeneration", while Ian Ashdown says flatly "at the light levels encountered with typical electric lighting, there is no evidence to indicate this". Lorna says "blue light during the day is fine", but Michael says "If you want to have a noticeable effect on retinal health you'd block 90% or more" - though he thinks it's unnecessary. It can be difficult for someone like me to figure out what common sense really is. "On balance the evidence suggests but does not yet confirm that blue light is a risk factor for AMD", written by opthamologists, seemed like a reasonable position. It's maybe not too far out of line with the rest of what you wrote?

    The bottom line is that I wear UV protective lenses and try not to spend too much time in the sun, like most people. I'm not really worrying about retinal damage from blue light. But I'm starting to think that maybe sitting in front of the window most of the day, looking at the sky above my computer screen, is something I might consider changing.



  • @herf said:

    1. Computer screens are designed to emulate paper viewed under bright office lighting, and compared to fluorescent light reflected by paper, it is extremely hard to argue that LED screens cause more harm.

    Oh, absolutely! The idea that computer screens and smartphones are somehow more dangerous than being in other types of daylight-balanced lighting, or daylight itself, is utter nonsense. As I've been googling some of the products, I'm seeing this implied over and over. Re-reading what I quoted from the AOA, they're implying the same thing. And clearly @elisadelina has bought into that. That's just wrong.

    The story about Boots pushing £70, 20% blocking lenses to protect you from your "gadgets", does seem ridiculous. I agree that companies shouldn't be allowed to make health benefit claims for their products, when there's no conclusive evidence to support them. To be honest, I hadn't really looked at what's on the market. I only know that it should be possible to make a 90%+ reduction longpass filter lens, without being extremely expensive, and that it would give more precise control over the cutoff frequency than can be achieved by modulating the LCD filters in a monitor. In other words, to block the wavelengths shorter than 450 nm that may (or may not) be harmful, while passing the 480 nm and longer wavelengths that are beneficial in the daytime. I guess I assumed that's what they were doing.

    Even if they were though, it seems that the evidence for blue light's contribution to AMD isn't conclusive enough for companies to legally make claims of medical benefits.

    Still, it seems to me there's some evidence about long term chronic retinal effects of blue light in general (not specifically computer screens), and that some sort of eye protection measures could be beneficial. Again, I'm not talking about acute effects, which is what IEC62471 and I think Van Norren are dealing with, 12-hour exposures and so on, but fifty-year exposures. Figuring out what those measures should be though, is beyond me at this point. It is difficult for me to understand the "95% or nothing" position.


  • f.lux team

    Elhem, it is not a question of challenging me, it's a question of ensuring we post the most accurate information we can. I agree with you about both the benefits to easy access to information and the trouble of armchair experts. We must all be very aware of making incorrect assumptions. This is a difficult topic, and an area of active, ongoing research. Nobody knows all the answers to these questions.

    Everything from stronger nightly melatonin production to reduced levels of ADHD to the prevention of myopia has been linked to appropriately bright daytime light exposure. It helps mitigate the effects of artificial light at night too.

    I will tell you that I have begun spending more time sitting in front of windows and looking at the daytime sky, making sure that I see bright light at the appropriate time of day. There is not evidence that says that anyone must filter 90% of light in a normal, healthy eye. But for someone who has to pay closer attention to their retinal health, filtering 10% of inappropriate light will do nothing. Because you have concerns about this I strongly recommend you bring this up with an ophthalmologist, who can give you the best advice for your needs.

    It would be a terrible disservice to spread fear and uncertainty about healthy people seeing light during the day, and we will not do that on our forum.



  • @lorna said:

    Everything from stronger nightly melatonin production to reduced levels of ADHD to the prevention of myopia has been linked to appropriately bright daytime light exposure. It helps mitigate the effects of artificial light at night too.

    I'm not sure what you've done to the forum, but I LOVE selecting text, clicking reply, and have it auto quote, that's SO much easier! Anyway, I have ADHD, and I'm near sighted so both of those strike my interest. Could you expand a bit on those topics?

    I've seen several "links" or correlations to bright light in the daytime preventing myopia, but I've not seen much about ADHD. I love this thread by the way, you're really explaining so much of this, and I love when we can pull information out of you and @herf so thanks!


  • f.lux team

    @Tungsten_smooth An incredibly high percent, around 75% of children and adults with ADHD also have delayed circadian timing. It's not strictly related to light timing - lots of ADHD patients have irregular meal times, and there is a lot of research looking for other internal clock components - but there's a very strong correlation with sleep issues and ADHD. Sleep deprivation in adults in lab conditions can induce textbook ADHD symptoms (more here: http://www.nytimes.com/2013/04/28/opinion/sunday/diagnosing-the-wrong-deficit.html?_r=0).

    We already know that getting bright light at the right time of day can help improve sleep quality and sleep timing. There seems to be an association between ADHD and sunlight levels too:
    http://www.brainclinics.com/association-adhd-intensity-sunlight-adhd-prevention



  • @lorna Well thank you for that, I'm quite sure I have... sleep onset insomnia, and it's, well, it's not getting any better. I've noticed in recent years (6-7+ years) it will take at least an hour (but usually about two) for me to truly feel relaxed and want to sleep. There's just so many interesting things to think about-it's not stressful stuff, it's mostly what I did that day, what I need to do tomorrow if there are tests, and then I think about my life and technology after that. Damn brain won't turn the hell off!


  • f.lux team

    @Tungsten_smooth Ahh, sorry to hear that. :(


  • f.lux team

    You also asked about the sunlight and myopia connection as well, and I needed to look up some of the sources for you here because I know less about this topic.

    The retina produces dopamine in daylight. And we know that dopamine / dopaminergic meds change the shape of the eye (atropine can even slow down myopic progression in kids).

    A lot of people with ADHD report photophobia, and wear sunglasses(47%), which might even lead to additional sleep delays. About 70 - 80% of kids with ADHD also have visual acuity problems.

    Here are some sources, some are paywalled, but if you are still a student your library might have access:

    High Prevalence of Self-Reported Photophobia in Adult ADHD, Kooij and Bijlenga 2014:
    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4261727/

    Light Levels, Refractive Development, and Myopia - A Speculative Review, Norton and Siegwart, 2013: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3742693/

    An updated view on the role of dopamine in myopia, Feldkaemper and Schaeffel, 2013:
    http://www.sciencedirect.com/science/article/pii/S0014483513000432

    I realize I sound like everyone's grandmother right now but if you want to do something simple to help your retinal health and make it safer to see blue light, the easiest thing to do is eat leafy green vegetables. Spinach and so on. Orange and yellow is okay too - carrots and corn will also help. Mammals can't make the pigments needed for best retinal health so we must get them from plants. Anything green (and from plants, so green m&ms don't count) will provide your body with the right materials to help keep your eyes healthy. More here: https://en.wikipedia.org/wiki/Carotenoid



  • @Tungsten_smooth said:

    @lorna Well thank you for that, I'm quite sure I have... sleep onset insomnia, and it's, well, it's not getting any better. I've noticed in recent years (6-7+ years) it will take at least an hour (but usually about two) for me to truly feel relaxed and want to sleep. There's just so many interesting things to think about-it's not stressful stuff, it's mostly what I did that day, what I need to do tomorrow if there are tests, and then I think about my life and technology after that. Damn brain won't turn the hell off!

    I have some tips that I would love for you to try:

    1. Near bedtime, write all of these things down on paper. Don't use a computer to do it: you have to use a pen or a pencil. It's a massive difference between writing and typing.
    2. After that, spend a few minutes sitting quietly in silence with your eyes closed. Or instead of silence, use white noise to raise the sound floor to drown out distracting noises. Calm yourself and let your mind do what it needs to do. The longer you do this, the better.
    3. As often as you want each day, spend a handful of minutes in total silence with your eyes closed. It doesn't have to be perfect silence because you can instead use a white noise sound machine to drown out distracting noises, like the Dohm. The longer each session is, the better.
    4. You might even benefit from taking melatonin right before bed. I have mild Autism and I read years ago that people with Autism naturally produce insufficient amounts for proper sleep. So if I don't take my melatonin, then I end up with the same problem you have. Do you have Autism at all? You might. Lots of people have it and don't realize it.
    5. Increase your intake of Folate. This can help a little with anxiety. 400 to 800 mcg per day is plenty. Don't overdo it. I like Solgar's Folate, the one that's in the form of Metafolin (L-methylfolate). They are dry tablets that are meant to be swallowed, but can be easily chewed up and have a mildly sweet sugar-like flavor.
    6. Use some breathing exercises to your advantage.
    7. Try to leave at least a 3-hour gap between the last thing you ate or drank and when you go to bed. Going to bed too soon after your last meal of the day (which, for most of us, is our biggest and hardest-to-digest meal) is the reason most people have a hard time going to sleep. It's also one of the causes of nightmares and waking up too hot in the middle of the night - even if the room is cold.
    8. If you exercise regularly, then try to leave at least a gap of at least 6-8 hours before bedtime. It is absolutely mind-blowing how long it takes for the body to truly calm down after a workout. If you can't do this, then you may need to use special relaxation techniques and exercises after a workout, but that can't replace working out earlier in the day, but it would be better than not exercising anymore. Think about what it would be like to live outside in the wild hundreds of miles away from artificial light: you naturally get your exercise during the middle of the day looking for food, but the later part of your day is spent coming back to your living area and eating the food you found before you lose the light that the sun provides. This is hardwired into us.
    9. Try a sound machine instead of sleeping in silence. I use the Dohm, and I'm serious: I sleep better these days because of it.

    I can't think of anything else.



  • @lorna said:

    @Tungsten_smooth An incredibly high percent, around 75% of children and adults with ADHD also have delayed circadian timing. It's not strictly related to light timing - lots of ADHD patients have irregular meal times, and there is a lot of research looking for other internal clock components - but there's a very strong correlation with sleep issues and ADHD. Sleep deprivation in adults in lab conditions can induce textbook ADHD symptoms (more here: http://www.nytimes.com/2013/04/28/opinion/sunday/diagnosing-the-wrong-deficit.html?_r=0).

    Well having ADHD seems quite shitty going by that link. There's so much that can go wrong--that article highlights a lot of downsides to ADHD and they are all awful. Thankfully I don't have trouble breathing in my sleep--I'll never know if I did as an infant, I'm not sure my parents checked that, and I never asked, too young at the time. It says that could have a permanent neurological effect! That's HORRIBLE! Something we just take for granted could strongly impact your life in such a negative way forever! That's enlightening! Great!



  • @Tungsten_smooth said:

    @lorna said:

    @Tungsten_smooth An incredibly high percent, around 75% of children and adults with ADHD also have delayed circadian timing. It's not strictly related to light timing - lots of ADHD patients have irregular meal times, and there is a lot of research looking for other internal clock components - but there's a very strong correlation with sleep issues and ADHD. Sleep deprivation in adults in lab conditions can induce textbook ADHD symptoms (more here: http://www.nytimes.com/2013/04/28/opinion/sunday/diagnosing-the-wrong-deficit.html?_r=0).

    Well having ADHD seems quite shitty going by that link. There's so much that can go wrong--that article highlights a lot of downsides to ADHD and they are all awful. Thankfully I don't have trouble breathing in my sleep--I'll never know if I did as an infant, I'm not sure my parents checked that, and I never asked, too young at the time. It says that could have a permanent neurological effect! That's HORRIBLE! Something we just take for granted could strongly impact your life in such a negative way forever! That's enlightening! Great!

    My mom said that I had a breathing incident when I wan an infant, and I have Asperger's Syndrome. I doubt that this is why I have it because it's something a person is born with, but still, I'm sure that incident damaged me somehow.

    You can have trouble breathing while you're sleeping and not know it. If you are told that you snore while you're sleeping, then that's a sign that you could be having trouble.



  • @lorna said:

    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4261727/

    "Among adults with ADHD, the majority has an (extremely) late chronotype and a delayed sleep phase (7, 8)."

    Here's the beginning of that paragraph, but you may or may not be able to recite all this if you've read it before:
    "From chronobiology studies, we know that there is a link between retinal function and the circadian rhythm. " That's the sentence that really kicked it off.

    Well that just went from vision right back to sleep! That just shows how important it is. A paper about vision just starting discussing sleep. How did that happen? I guess eyes and sleep are related..., but, yes, that definitely explains my late sleeping schedule, shucks. I tell you, you just poured a bunch of negative information into my screen! Thank you though, it's worth it to learn. At least I can be aware of all this stuff, I can't thank you enough!



  • I think the article is just talking about the light that enters your eyes while you are awake. You know, blue light, red light, bright light, dim light, all the stuff that we already know. I think they're just describing it differently.



  • @TwoCables Thanks, I was going to post that I was confused as to why the subject changed so abruptly but you really picked up on that quickly, thanks. Yeah, that seems to be the case, it's discussing how the light goes and works it's magic in the brain.


  • f.lux team

    @Tungsten_smooth Yes, it's all related very closely. The retina is really important to circadian rhythms. It's a lot to take in, especially when some of it rings true. But I hope you won't feel too much like it's all bad news. Reading too many studies online can have that effect sometimes...



  • @Tungsten_smooth said:

    @TwoCables Thanks, I was going to post that I was confused as to why the subject changed so abruptly but you really picked up on that quickly, thanks. Yeah, that seems to be the case, it's discussing how the light goes and works it's magic in the brain.

    Yeah, it can seem like magic can't it? Every time I swap out my Switch 3-Way LED lights for my red FEIT LED lights (right after switching f.lux to 800K), I can truly feel a difference immediately.

    Then as I get super close to going to bed, I turn off one of the two red LEDs (to lower the brightness), and again I can feel a big difference in the way I feel.

    During the whole time I'm using my red LED lights with f.lux set to 800K, there are SOMETIMES occasions where I'll want to look at something that needs more accurate color. So, I'll disable f.lux for a minute while I look and once again, I immediately feel the difference; I feel more alert. Then when re-enable f.lux, I immediately feel a big difference yet again. It's like magic. lol I love it!

    Or how about sunlight? lol If I happen to have woken up at around sunset, then I have to wait until sunrise to really begin to feel more lively and ready to go. Then on a sunny day, if I open and close my blinds (room-darkening), I again feel a difference.

    The affect that light has on us from its color temperature to its brightness is absolutely mind-blowing to me. Until I discovered f.lux and became aware of this stuff, I never noticed it. I mean, seriously: I just didn't notice the effect that light has on me.



  • @lorna said:

    @Tungsten_smooth Yes, it's all related very closely. The retina is really important to circadian rhythms. It's a lot to take in, especially when some of it rings true. But I hope you won't feel too much like it's all bad news. Reading too many studies online can have that effect sometimes...

    lol yep, it's like having a simple headache and you go on the internet read all the possible reasons for having a headache and the next thing you know, you think it means you're going to die today.

    The internet can be useful, but it can also be very destructive when you believe everything you read, or read things into things that aren't even there.

    Unless you are TRYING to damage your retinas, I seriously doubt they're being damaged unless you like to regularly shine lasers into your eyes and look directly at un-shielded super-bright LEDs from 1 inch away from your eyes. Or, if you like to look directly at the sun every day. Some people do that you know; they call it Sun Gazing, and it's extremely stupid to do. Personally, my version of Sun Gazing is simply closing my eyes and pointing my face directly toward the sun.

    I'm getting off-track though. lol Really, if you are just doing normal things every day (nothing super unusual in terms of the light you're exposed to or the types of light), then I'm sure your retinas are just fine. As has been said, it isn't exactly easy to damage your retinas unless you do very specific things that causes damage and those specific things are things that most of us never experience.


  • f.lux team

    @TwoCables I do exact the same thing - I love how blue the world looks when I open my eyes again.



  • @lorna said:

    @TwoCables I do exact the same thing - I love how blue the world looks when I open my eyes again.

    hehehe yeah that's a strange phenomenon. I guess that means the rods and cones were overloaded a little bit.



  • @lorna I had to take a break reading the myopia link, phew, lot of text. Yeah, it's not all bad news, it's just birth defects is what I get from it, and I'm sure I have a lot of those for reasons I'm not getting into. It's great to learn and be aware of all this, so if I have children I'll monitor their breathing very closely, and hopefully that "one time event" I can somehow remedy that and save their life from ADHD. On that note, if an infant does start breathing abnormally in their sleep, or maybe if they stop breathing--what do you do? That would be cool to know.



  • @lorna said:

    @TwoCables I do exact the same thing - I love how blue the world looks when I open my eyes again.

    O.K. so I'm not the only one who does that! Cool, glad to know I have moderately normal color vision, although the links said that having ADHD could result in the blue spectrum being different, but it didn't say in what way, so I guess I'm fine.



  • @Tungsten_smooth said:

    @lorna I had to take a break reading the myopia link, phew, lot of text. Yeah, it's not all bad news, it's just birth defects is what I get from it, and I'm sure I have a lot of those for reasons I'm not getting into. It's great to learn and be aware of all this, so if I have children I'll monitor their breathing very closely, and hopefully that "one time event" I can somehow remedy that and save their life from ADHD. On that note, if an infant does start breathing abnormally in their sleep, or maybe if they stop breathing--what do you do? That would be cool to know.

    I would guess that your best course of action would be calling 911, unless you are a doctor and know how to save the baby's life on the spot.



  • I thought of this when when read about how important breathing is:

    https://youtu.be/6vERCnJ-DLw

    It's a great movie with an awful crappy ending.


  • f.lux team

    @Tungsten_smooth Baby monitors are getting incredibly sophisticated, they have all manner of new things coming out to monitor health. If the child has a physical obstruction that's causing the problem, like enlarged adenoids, the treatment might be to remove them. In that case you might notice snoring. I feel like you might enjoy getting first aid certification!

    Editing to answer your other question, adults with ADHD can have trouble with depth perception and the blue region of the spectrum (and extra sensitivity to light).



  • @lorna Would sensitivity to light include complaining about having to turn a frosted white Incandescent bulb that looks to be at least 75w at night be included in that? I don't think I'm sensitive in the daytime and try to welcome all the light I can get.



  • @Tungsten_smooth said:

    @lorna Would sensitivity to light include complaining about having to turn a frosted white Incandescent bulb that looks to be at least 75w at night be included in that? I don't think I'm sensitive in the daytime and try to welcome all the light I can get.

    I find that when I'm tired and when my body is actually producing its own melatonin, I am far more sensitive to light and I feel much better with dim light. I think it's our body's way of saying, "dude, would you just go to sleep already? Good god."



  • This thread has been wonderful! Could we also dig up how much the chances are that offspring from adhd patents will have all this?



  • @elisadelina yea no f.lux is wrong on this matter. The frequency / quality and source of the light is massively important.


  • f.lux team

    @yourmom We're referencing doses of blue light from the international hazard documents (e.g. IEC 62471, ICNIRP, and ANSES). There is a broad consensus regarding these doses of visible radiation, so if you're saying you disagree with that body of research, please elaborate.

    There is indeed a lot of marketing that ignores dose and focuses only on wavelength. This approach is incorrect - there's a threshold of energy known to cause harm to the human eye. Light is measurable and quantifiable, and if you don't have enough energy to damage cells, you don't have enough energy to damage cells.

    The potential blue light hazard from the brightest computer monitor we know is less than 10% of what you'd see from just blue sky, removing any direct sunlight. If you were to look at a regular sidewalk in daytime, that exposure is hundreds of times more powerful than your monitor screen - this is how we are hoping to get people to think about light, in real power units and not just subjective colors.



  • @lorna I get all that, I disagree I think the flicker rate of the source of light (artificial light ) and the overall spectrums balance with other colors is what makes the real difference. Not the intensity in terms of power units or specific wavelengths. The most intense of blue light is always balanced by red in the sun's light. It changes the effect on physiology of the retinohypothalamic tract, the setting of superchiasmatic nucleus circadian rhythm and all the downstream molecular clocks of our organs.


  • f.lux team

    @yourmom I think you owe the thread some clear language here - you began by saying "f.lux is wrong", and you have made no statement at all that could support this position.

    f.lux launched nearly nine years ago, and the hypothesis behind the product is that displays make enough light to disrupt circadian rhythms at night. We understand these biological systems and the research behind them very well, and we have helped to popularize the research on the non-visual effects of blue light and its effects on the central clock, the SCN. As well, we frequently criticize flicker and distribution of light that leads to glare.

    A majority of the non-visual effects of light are conveyed to the SCN through a single photoreceptor, and a non-visual system that achieves the "balance" you refer to is not supported by any literature. Even though the cones are believed to convey extra information to the ipRGCs, they are doing so using much of the same circuitry that drives color perception, not by some magic additional system.

    I have previously made notes about the claims made about beneficial effects due to IR and the retina here: https://forum.justgetflux.com/topic/3809/which-is-the-best-light-troughout-the-day-to-stay-in-front-of-pc/6
    And again, I will say, the evidence in rodent studies suggests that these effects happen only at extreme irradiance levels, many hundreds of times greater than indoor lighting

    It is very reasonable to talk about what you see (these colors don't match) or how you feel (this flicker makes me feel eyestrain), but to impute physiological harm (as some do) to these effects without any evidence is a mistake. Some things are just uncomfortable, but they are not known to cause any lasting harm.

    We are facing a similar problem with circadian effects - people believe, falsely, that changing color temperature a little bit will positively affect circadian rhythms, when in fact, small changes are likely to have very small effects. Eye strain and circadian/alerting light are not likely to be the same thing for most people.

    When you are talking about non-visual physiological effects of light, you can't perceive directly everything that is going on. Dose matters and measurement matters, and you would be well served to read up on both.



  • @herf Your so close to completing getting it. I'm well read on the subject. It would be foolish to get emotional bout it. So lets just clarify a bit bout ipRGCs.

    Intrinsically photosensitive retinal ganglion cells (ipRGC) and their connection with the suprachiasmatic nucleus ( circadian rhythm center )
    There is a third type of cell in your retina called the intrinsically photosensitive retinal ganglion cells abbreviated ipRGC’s. These cells utilize a different photopigment called melanopsin, are much less sensitive to light, respond to light slowly, have far lower spatial resolution. Although these cells do have some role in vision / motion detection / brightness detection their primary function is signaling ambient light levels (irradiance) to the brain.
    ipRGC’s express a melanopsin allowing them to directly respond to light, and they send axon projections to a brain target known to be involved in circadian photoentrainment and photic suppression of pineal melatonin release. The main center involved with the photoentrainment aspect is the Suprachiasmatic Nucleus (SCN). The ipRGC directly sends out a ton of axons to the SCN indicating its pivotal role in circadian rhythm management.

    Daily rhythms in mammalian physiology and behavior, collectively called circadian rhythms, are controlled by a tiny cluster of cells in the SCN of the hypothalamus. SCN neurons possess a transcription/translation-based molecular clock that allows them to autonomously regulate activity patterns in near 24-hour rhythms, the SCN must be reset periodically so that circadian rhythms are synchronized (or “entrained”) to the light/dark cycle. Light is by far the most potent circadian entrainment cue, and ipRGCs are the primary cells that carry this signal since eliminating these neurons abolished photoentrainment in mice (Hatori, 2008; Goz, 2008; Guler, 2008).

    The reason f.lux is good is because you can run it on red all day. Blue light will turn out to be the most harmful of all non-native EMF. Unbalanced blue is massively important when it comes to the timing of all your bodies systems and I'm not just talking about the eye's / dopamine overuse / melatonin production inhibition. Great poinnt about the rats/ IR into the retina and your right it was way above indoor light levels. You know whats way above indoor light levels. The outside world, more than any app, making sure your skin and retina's get exposure to unfiltered am sunlight is critical

    Great po


  • f.lux team

    I am literally facepalming right now.



  • @lorna continue in fact don't stop , keep facepalmed permanently. lol


  • f.lux team

    @yourmom Some online gurus (the ones I suspect you're reading) start with real science, and indeed, the basic circadian research is supported by thousands of studies. You can cite that all day - we know all the references too.

    The trouble is when an online guru is your sole source of information, you don't realize when it has gone off the tracks into a place where the science doesn't exist. "the most harmful of all non-native EMF" is simply BS, and you're not citing a dozen studies there, because they don't exist.

    There is no "unbalanced" blue like you're describing. Lighting that matches daylight spectrum for all known photoreceptors, seen at indoor levels (100x lower than outdoor light) is not known to harm the retina. There is just no literature that supports this, and you're listening to the wrong people if you believe it.


  • f.lux team

    @yourmom I'm going to go enjoy my Sunday now, and I hope you do the same. Take a nice long walk outside. your lateral geniculate nucleus will thank you.


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