Filtering blue light
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This is interesting - are you comfortable sharing any details about the condition? I would like to know more about the mechanism so we could talk about the power involved.
Depending on the spectrum, f.lux can remove 90-99% of the light in this range, but if that matters is another question. The main reason is that being outdoors may give you 1000x as much light as you'd see from a computer screen. And also, at more extreme f.lux settings, your regular indoor lighting will give you a lot more exposure than your screen does.
Where screens seem to matter the most is using them right before bed, when they are brighter than the rest of the lights in your house.
To expand on this:
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A display has a very tiny amount of HEV/UV light, and almost none below 420nm: https://fluxometer.com/rainbow/#!id=Thinkpad T440s/6500K-ThinkpadT440s
So really, what you'd like to understand is what is the dose required from 420-480nm to stimulate your condition. -
Then, compared to daylight, the brightest display makes only 1/1000 as much power in the <480nm region. So if it's a question of "power" (and most things like this are), then the screen would be a pretty minor input even compared to standing next a window when the sun is up.
And to answer your question about brightness, any change that removes 480nm light will affect the luminance somewhat, but you definitely can adjust luminance by a "small" amount while removing most of the blue light.
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@herf Thank you for your reply. I understand your skepticism; I don't quite understand it myself. I have lupus, which makes me sensitive (skin and systemic) to sunlight. Many Lupus people find fluorescent lights hard to work under. I also have Sjogrens which attacks my eyes. Several months ago, I had eyelid surgery, which has mostly healed by now. But the surgery seems to have made my response to "UV" go bonkers. Sitting in front of my 27" iMac makes my eyelids swell and my eyes turn red and irritated. But the computer is nothing compared with watching TV, even from far across the room, wearing my Gunnar gaming glasses (all UVA, UVB, and 65% of blue below 470, I think) and sunscreen. I also wear the glasses for the computer and that helps a lot. I can feel the burning when it happens, but the autoimmune swelling happens in the subsequent hours and lasts maybe 20 hours. I wear dark sunglasses or my gaming glasses everywhere I go during the daytime, as well as the usual long sleeves, hat, SPF 100, etc. But still my eyes swell slowly during the day and relax some overnight (without electronics). If I watch any TV at night, my eyes are still very swollen in the morning. I have changed the computer background to dark gray. Some of the info I've read implicates HEV blue, but I have no personal evidence of harm from specific wavelengths. I'm not photosensitive, so I like brightness when I work. I do freelance work on the computer, so I have to find ways to make it better. I'm happy to hear any suggestions you may have!
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Are your displays and lights all LED, or do you have CFL/CCFL (perhaps in the TV)? There is basically no UV in LED sources, but some CFLs may produce it. Also, is the TV visually brighter than the iMac?
To test if particular wavelengths are involved, the simplest/cheapest way I know is to try $8 glasses like these, which block <530nm almost entirely:
https://www.amazon.com/Uvex-Blocking-Computer-Glasses-SCT-Orange/dp/B000USRG90
If you want something more stylish, look at lowbluelights.com.Most sunglasses only block 90% of light, but these block >99%, so they can be useful during the day as well.
An iMac is very bright, but if it is dimmed to one of the lower settings (within 4 ticks of the bottom), it would usually not have a large circadian impact. Whether or not this is related to what's going on for you is a separate question, and one I'm not qualified to answer!
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@herf Thank you for the UVEX reference. Those orange glasses make a huge difference. They are much more effective than the Gunnar gaming glasses, suggesting that it is the increased blue blocking making the difference. I can wear UVEX for computer and TV and gamer outdoors without my eyes swelling. Since I have to wear these huge UVEX glasses with my readers perched precariously on top, I've ordered some blue blocking glasses from readingglassesetc which also appears to have blue block technology - they should arrive any day. So my question is - can f.lux do the same thing to my computer screen - block out UV and blue light all the time? And I do hear you on the presence of UV sources indoors and outdoors ( I used to be a research chemist), but this is my experience, and empirical results are all I care about at the moment. Thank you for all your help.
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@Bomag Random thought, do you think you might be sensitive to flickering LEDs? Many LEDs dim by flashing on and off, with the idea that it is too quick for people to see. As someone who can see flicker at speeds way beyond what "should" be possible, I wonder if that's part of what's causing your discomfort.
Looking forward to hearing your review of the blueblockers you got - lots of companies claim they block blue light, but that seems to mean different things to different people. For circadian light, the successful blue blockers are pretty deep orange, like Uvex. -
Yes, that could easily be the cause instead. Although would that be ameliorated by UVEX glasses? And if so, are there any other fixes for it, on either the source or me?
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UVEX also makes these (very stylish) fit-overs:
https://www.amazon.com/Uvex-S0360X-Ultra-spec-SCT-Orange-Anti-Fog/dp/B003OBZ64M/ref=sr_1_2And yes, we think f.lux should have a similar effect - the UVEX-equivalent f.lux setting is about 1200-1500K (depending on the display), but you can also do a lot with dimming also. Here are two ways to get "5 melanopic lux":
https://fluxometer.com/rainbow/#!id=Thunderbolt 27/6500K-Thunderbolt27&filter=filter/UVEX SCT Orange
https://fluxometer.com/rainbow/#!id=Thunderbolt 27/1200K-Thunderbolt27 -
@Bomag It's a good question and I don't have a certain answer for you. It may help just by reducing the peak brightness of the flickering, or it might be something about eliminating flickering in specific wavelengths. Just guessing. There is a a lot we don't know!
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Hi...i am a new user here. As per my knowledge the main reason is that being outdoors may give you 1000x as much light as you'd see from a computer screen. And also, at more extreme f.lux settings, your regular indoor lighting will give you a lot more exposure than your screen does.
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Hi...i am a new user here. As per my knowledge the main reason is that being outdoors may give you 1000x as much light as you'd see from a computer screen. And also, at more extreme f.lux settings, your regular indoor lighting will give you a lot more exposure than your screen does.
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Hello,
yesterday I have done some measurements of melanopic lux depending the setup of the blue filter of my samsung galaxy S8+.
The result is amazing. Without bluefilter I measured directly at the display with full brightness 751 lux (melanopic).
Then I activated the blue filter function of the phone to maximum value and the melanopic lux get reduced to 224 lux. (-70%)
But to answer your question, the general illumance also changed from 597 lux to 393 lux.
Result: yes it get darker, but the relation of the blue effect is also down to half.
I have published all the measurement values online (https://www.ledclusive.de/blog/melanopische-lux-am-beispiel-blau-filter-eines-smartphones-gemessen/). It is written in German, but the table and the graphics already should help to understand. -
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