Blue light and the retina
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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.
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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
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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:
- 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:
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.
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@herf said:
- 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.
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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.
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@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!
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@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
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@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!
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@Tungsten_smooth Ahh, sorry to hear that. :(
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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/S0014483513000432I 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
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@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:
- 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.
- 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.
- 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.
- 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.
- 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.
- Use some breathing exercises to your advantage.
- 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.
- 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.
- 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.
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@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!
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@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.
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@lorna said:
"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!
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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.
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@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.
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@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...
@lorna
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@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.
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@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.
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@TwoCables I do exact the same thing - I love how blue the world looks when I open my eyes again.
@lorna
