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  • tfouto Level 1 Level 1



    on the other hand, be careful. Maybe it's not a good idea to have your monitors at a maximum brightness, since it may cause severe eye pain, a few days later when you become sensitive.


    This happen to me. The effects are not imediate, but when they appear it's at full force...

  • tfouto Level 1 Level 1



    do you have polarized sunglasses? If so, can you put them on and see through your different devices including your surface? To me the most irritable screens are the one which are polorized and with colours. you see rainbow of colours. On your Sasmung SA850D you will only notice black and white as you move your head.


    This only work with polarized sunglasses, not normal sunglasses...

  • mojarvinen Level 1 Level 1

    Hey, thanks for the tip!



    I'm just now viewing my Surface Pro 2 with my polarized sunglasses and lo and behold, I see rainbow colours in white areas.  When I  turn my head, the display does not go dark, like with my HP display or my Galaxy s2.


    So in addition to the DSLR tests, this could be a test that reveals one source of eye strain in a display.


    Thoug, I tested also with the iPad 1st generation and that behaves almost like the HP display, that absolutely does not cause eye strain. However, it does not go completely dark, so clearly there is a difference in the polarization layer of the iPad.


    I has actually hoping that the iPad would have displaye similar rainbow colours, so then it all would have made sence, that the polarization layer is the culprit in the display.


    But when I get this Surface sold and start hunting for an alternative, I'll bring my polarized glasses in addition to the DSLR to the game, so when I find a display that passess the DSLR tests and does not show rainbow colours in with polarized sunglasses, I can be fairly safe that it will not irritate my eyes.


    Isn't this difficult?

  • mojarvinen Level 1 Level 1

    ah, forget it. False alarm. I tested the Xperia z1 which I have confirmed that it does not irritate my eyes - it shows similar rainbow colours as the surface pro.


    It's maddening that there seems to be no conclusion on what is causing the eye strain.


    PWM is one for sure, no doubth about it but that does not explain iPad and Surface Pro eye strain.


    Or then those have it, but at such a high frequency that the DSLR test does not detect it, but optic nerve still does.

  • tfouto Level 1 Level 1

    If you lower the brightness on your Surface Pro does your SLR detects the PWM?


    One think the Z1 has 'bad angle' views. Maybe that's not related, but maybe polarization might be slightly different...

  • tfouto Level 1 Level 1

    I will buy photodiodes and connect to audio connect of the pc. Then with a free software (oscilloscope) i will measure easily the PWM even if its high frequencies that SLR cannot detect...


    It seems there is also software for Android... That way in a portable way you can walk to the stores and measure PWM even if it's high frequencies...









    BTW Xperia Z1 is TFT and not IPS..

  • spprt Level 1 Level 1

    I was wondering if sound card oscilloscopes can detect very high PWM frequencies. I think many sound cards have like 22,000 Hz sampling rate, so maybe they can't detect insanely high PWM?

  • StefanD13 Level 1 Level 1

    hi tfouto,

    I use this a phototransistor connected to this:

    SainSmart NANO DSO201 Oscilloscope ocket-Sized-Portable-/261073771386?_trksid=p2054897.l4276


    To my calculations it should be able to detect up to around 22kHz (limitation is the phototransistor), and I could confirm for example the 8kHz measured by on the Dell U2413 as well.


    All Apple I tested shown no PWM (but still huge eye strain)...

  • tfouto Level 1 Level 1

    Mine has 192khz:



    I dont know how much the photodiodes can handle...

  • tfouto Level 1 Level 1



    What phototransistor do you have?


    BTW did you measure PWM with the ipad with a really low brightness?


    If you lower the bright to lower levels does the strain remains?

  • Jessiah1 Level 1 Level 1

    ArtechokiQ "Sometimes I get excited by seeming success but then oops I was wrong"


    I agree, even with my ridiculous sensitivity I sometimes fool myself with excitement into believing something is working, the brain is certainly a powerful motivator but it cannot fool you forever.


    There seems to be a lot of good science going on here with adjustments and tweaks to monitors, IMO I believe you guys are doing a good job mitigating the effects of the LED or fluorescent backlighting however the root cause is still there (Most likely spectrum combined with some sort of flickering). The good news is for some people you have found settings that will make computing possible, for myself I wish I could try some of the devices you guys are tweaking so I could help; if you can make LED back lights anywhere near tolerable for me you would definitely be helping everyone as I have not found a single LED light source I can tolerate!


    One question: Has anyone combined any of this research with AC/DC power filtering at the same time?


    Happy holidays everyone, I wish you all a headache and eyestrain free holiday season



  • StefanD13 Level 1 Level 1

    Hi tfouto,


    I use this one: bp103


    Yes of course measured at least under 50% and in general with Apple devices, the brightness level didn't influence the eye strain.

    On my work computer however setting brigthness to 100% (and color depth to 16bit) is the only way I can work.




  • mojarvinen Level 1 Level 1

    StefanD13 have you tested any of the displays that I've found not to cause problems?


    Or any display that does not require tweaking to be tolerable.


    The HP ZR2740w is truly a great display - it has a great image quality and does not cause any eye strain at any setting. 


    Would be great if some others that have this problem, could try that out, so at least we could confirm what does not cause the problem. Then examine the differences between the HP display and E.g  an Apple display that causes problems.

  • StefanD13 Level 1 Level 1

    Hi mojarvinen,


    I have tried the ZR2740W as well as the xperia Z1. Although both no PWM they were for me still uncomfortable (still not as bad as Apple devices).

    My assumption is still the dithering, although in the mean time I'm almost sure that my nvidia card is not doing any dithering, so for the HP monitor probably the problem is the screen internal dithering.

    I have tried as well the Dell U2413 and it was similar with the HP.

    I have not tried yet the Dell U2410, but I read it does FRC (meaning temporal) dithering from 8 to 10bit.




  • mojarvinen Level 1 Level 1

    Interesting. I don't want to dwell on this but did you really have the chance to try the HP display long enough and while not using any other offending devices -  with fully unstrained eyes?


    I find it even more strange that we would have so many types of eye strain. That while I get severe eyestrain from PWM an also some non PWM displays, the HP surely does not bother me at all. Did you test the v2 of it,  with less agressive anti-glare coating?