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  • Jessiah1 Level 1 (0 points)

    Mvanier, please continue discussing dithering I was in no way being critical of your inputs on that subject. My main point is that there are a range of symptoms here starting with what sounds like normal dry eye fatigue, moving to a more moderate eye strain issue and ending with something severe like my migraines and disorientation. I believe we have nothing close to a controlled scientific experiment here and everyone is saying "This works for me so it should work for you" just a little too much.


    It appears we do have some great research going on here with monitors, my post was more questioning why some of us cannot tolerate any form of LED light and have immediately severe symptoms and some of us are simply talking about an irritation of the eyes or moderate eyestrain.


    If only you and I were in close proximity to each other, we could test your monitor settings on someone severe like myself and we could answer some of those questions. The most interesting thing that could come out of this forum would be a controlled experiment with 3-5 of us ranging in symptoms, we could find common ground and possibly common solutions that could at least mitigate symptoms for most if not all people here. I do not have the expertise or the money to start testing different technology....


    Being that you seem to have different sensitivities than myself I have a couple of ideas and questions for you:


    1: Are you sensitive at night to LED tail lights on cars?


    2:When you say you get severe eyestrain from a device, does this include any other symptoms like headaches or is it just eye pain?


    3: The older 60hz fluorescent lighting you spoke of that bothers you, could you please try the Provencia coating under these lights and let me know if it helps? I am very curious about this!


    One closing thought I will leave you with: When my sensitivity started 3 years ago it was milder and I only seemed to have an issue with overhead fluorescent lighting. It was not until I was exposed to some very harsh very blue overhead LED lighting for a period of 2 weeks about 1 year ago this past September that I developed a hyper sensitivity to all LED lighting. This poses an interesting question, is it possible those lights did some kind of permanent damage to my already sensitive brain/eyes during those 2 weeks of migraine **** while I tried to keep my job? Also, will those like yourself get more sensitive as they get more exposure over time? I certainly do not wish my level of sensitivity on anyone, it is terrible however, are some people here headed down my road?



  • kvoth Level 1 (0 points)

    Yet again I see that people are using the displays that cause problems and try to mitigate it with glasses, grayscaling or something else.


    I am the one using glasses and grayscaling.


    The lights typically used in gyms/warehouses/offices make me feel bad. I can't get another "monitor" for that. The Crizal Prevencia glasses coating work.


    As for displays, I already have one that works. Dell U2410.


    I was pointing out the grayscale because I am a professional software engineer and I frequently work remotely and can't carry a 24" display around with me. Grayscale on my 2013 Macbook Pro Retina is literally the best scenario I've used a computer in for a few years.

  • tfouto Level 1 (0 points)

    jessiah 1,


    what "harsh very blue overhead LED lighting" was that? Was it really blue, or white?

  • Jessiah1 Level 1 (0 points)
  • Jessiah1 Level 1 (0 points)

    Kvoth, my wife has an Apple mac book pro, I will try the Grayscale method tonight and report out on how it goes tomorrow.

  • ArtechokiQ Level 1 (0 points)

    There is a way to increase PWM to higher frequencies on intel graphics cards.


    Here is the software that does it:


    Here is the free software he is using:


    There is also some programing guides on how the code for this works: art3.pdf

    and the code itself:


    I believe among all contributions to flicker namely:


    1. Dithering

    2. Matrix Level Refresh Rate

    3. PWM


    PWM contributes the most to our suffering. (Of course I might be wrong) On top of that blue light which is more energetic makes things worse. Kvoth was saying that Dell U2410 doesnot bother him, maybe because it doesnot use PWM at all. Please correct me if I am wrong.

  • ArtechokiQ Level 1 (0 points)

    I was just playing around with my NEC231wmi which is a CCFL backlit and has a dither free 8-bit IPS panel. I was under the impression that the monitor uses no PWM at full brightness, however I was wrong. The monitor started to bother me. I then discovered that it uses PWM at 180hz. I then used the IntelPWMControl software to change the frequency to 600hz, There is a way to increease it to 2100Hz on which I am still working.. Suddenly I can handle the monitor better. The matrix level still refreshes at 75hz and I am currently trying to increase it to 82 Hz for which I know this monitor can handle. So I have managed in some way to eliminate most of it: PWM and dithering. I just wish the matrix level could go higher as well. I ll keep you guys posted on this.


    PS: I am seriously looking into getting

    FORIS FG2421

    It has matrix level 120hz

    No PWM above 20% brightness

    The only worry is 8-bit +frc to produce 10-bit, but then I believe dithering is the lowest contributor to our sensitivity. It could be eliminated if colors are set low.

  • mvanier Level 1 (0 points)

    I'm glad you brought up the subject of 120Hz monitors, which are a comparatively new thing.  In principle, this could completely or almost completely eliminate dithering-related eyestrain for the vast majority of people.  In practice, it is going to depend heavily on whether the video card supports 120Hz updates.  This is a promising avenue for the future.  OTOH I'm not convinced that "setting colors low" (I'm not exactly sure what you mean here) will do anything to eliminate dithering.  In principle, you would think that e.g. only using very basic colors (pure green, blue, red, black) would eliminate dithering, but in practice that doesn't seem to work.  There is no guarantee that selecting e.g. a pure red color will result in that exact color being sent with no dithering.  Computer video is complicated.

  • Jerry3012 Level 1 (0 points)

    Hi Jesse,


    I truely believe that this thing made permanent damages on my eyes/brain because I recently discovered that I get headaches from reading paper books! I was really shocked when I had to accept that fact!

  • mvanier Level 1 (0 points)



    LED lights on cars: I haven't had enough experience to tell.  If they flicker, they probably bother me.


    The eyestrain I get from e.g. Macbooks is mostly eye-muscle related.  It does result in a headache if it goes on long enough.  I think it's due to my eyes trying to track the tiny movement artifacts that are the result of the dithering/snow/whatever it is.


    60 Hz fluorescent lights: also eye-muscle eyestrain.  The light itself, though usually not very appealing, doesn't actually bother me.  It's the flicker that is annoying.  Maybe I should make a special trip to the DMV to test this, but I'm pretty confident of the result.  Interestingly, enough people had problems with this that it's very rare to find these kinds of fluorescent lights any more (the magnetic ballast kind); they have almost all been replaced by lights with electronic ballasts that also flicker, but at 30000 Hz!  I can handle that.  Also interestingly, some new "flicker-free" monitors (e.g. the Dell U2413) do PWM at low brightness only and at very high frequency (> 8000 Hz).  So the message is getting through.  Now if only more computer manufacturers would be aware of the problems with dithering...

  • Jessiah1 Level 1 (0 points)

    Jerry3012, that is not uncommon and there is some interesting info out there on how reading headaches can relate to this disease called "Irlen"  I will tell you that I have tried numbers upon numbers of different filtered lenses and nothing helps me yet as a solution, rose colored tint does help relax the eyes some but really does nothing for LED lighting in my personal case.


    I would like to state to everyone else the reason glasses/coatings/filters are an important part of this discussion is for the reason that it would be the least invasive solution if one of them were found to work. I am currently trailing migraine medications one by one and it is dreadfully plagued with side effects so far Who know's what other risks I am taking by going from one drug to the next. Another thought is the very real possibility of damage to our eyes, there are reports showing retina damage to test rats with exposure to LED lighting, it is quite scary when a technology overides health concerns because of what is seen as a greater good...ECO friendly lighting.

  • mvanier Level 1 (0 points)



    It's also possible to disable dithering with an nvidia card by adjusting the Xorg.conf file and setting

    'Option "FlatPanelProperties" "Dithering=Disabled"'.  For instance:



    Have you tried this?


    In the long run, I think Intel video cards are a better bet, since Intel open-sources their drivers and Nvidia don't.


    I wasn't aware that monitors did dithering on their own.  Even if they do, I'm only testing on monitors which I've found to be OK (i.e. no eyestrain) with older hardware/software combinations.  And, of course, there is the possibility that what is bothering us is not dithering per se, but something superficially similar.

  • Jessiah1 Level 1 (0 points)

    Mvanier, something is still going on with all fluorescent lights for me regardless of spectrum or flicker frequency, the anti-glare coating makes this all but go away. They did not bother me until 4 years ago, I cannot say the scientific reason why the coating works, even my contact at Crizal who is a PHD says they should filter spectrum but not flicker however, maybe we do not understand light well enough to know what the coating is doing? I would encourage you to try some exposure with the lenses under those lights that bother you, I would be surprised if they did not help, it is just a gut feeling. My theory is you may not be as sensitive as myself however if you became more sensitive you may have trouble with all fluorescent lighting as well.


    As for LED lighting on cars, where do you live? If in the USA I can provide info on what ones to check, the reason I am curious about this is because it sounds like you may not be aware of many LED lights that are out there and I am curious why. It would be really interesting to know if you only have issues with certain LED lights, that would be strange in deed...

  • Jessiah1 Level 1 (0 points)

    Mvanier, one other interesting input about monitors. I am currently using a 42inch Pioneer Kuro Plasma model# 4280HD, I can look at this right in front of it for about an hour before needing a break. I was using a Dell 22inch CCFL before this and needed to wear my anti-glare glasses at all times, very interesting right? No change in computer, just the monitor. The plasma is about 6 years old, I am not sure what back light it is using but I would guess some kind of fluorescent lighting. My Plasma may actually mark a certain point of change in technology where monitors became much more bothersome. I thought with the model number you might be able to use your expertise for some comparison of modern day technology to the old and possibly see something that stands out....

  • kvoth Level 1 (0 points)
    Another thought is the very real possibility of damage to our eyes, there are reports showing retina damage to test rats with exposure to LED lighting, it is quite scary when a technology overides health concerns because of what is seen as a greater good...ECO friendly lighting.


    I had my opthamologist run a battery of physical tests on my eyes. He said I have absolutely no physical damage to any parts of my eyes and that my eyes actually look very healthy, though slightly dry. He theorized that these issues are neurological.


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