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  • razureus Level 1 Level 1 (0 points)

    Today I added Moshi iVisior and will let you know on effects.

  • Jessiah1 Level 1 Level 1 (0 points)

    I have to share with everyone the best solution I have found in a computer monitor so far. I have been using my 42 inch Pioneer Kuro as a computer monitor instead of a TV for a week now, for whatever reason this older TV is the best thing ever to look at, only problem is when it dies there are no more....I would bet that new Plasma monitors are using LED back lighting now and would probably make me sick.

  • Kxtr73 Level 1 Level 1 (0 points)


    I was thinking about using Plasma too (Panasonic ST or GT series). As I read Plasma is somewhat similar to CRT techology and many found it excellent to his eyes.


    I have two question for You:


    - Plasma is using heavy dithering which is not visible only at a distance more then ex 2-3 meters

    ( I looked at Panasonic's in the shop and pixel shimmering was very visible. Is it not disturbing to You ?

    - What about image retention from static screens displayed many hours ?


    BTW. today's plasma are using the same technology as Kuro

  • GKphone Level 1 Level 1 (0 points)

    Anyone had problems with this build of 15 inch MacBook Pro late 2008 . I havent, but many many other Mac machines, before and after. Flicker rate i guess?? (  Like low engery bulbs, which i have the same problems with.)



    model number. MB470LL/A



    Is the only safe machine, when it comes to screens?

  • StefanD13 Level 1 Level 1 (0 points)


    How do you know is a LG screen? I have bought one as well, but is giving me immediately eye burn. Wanted to check whether LG screen, since when testing in the store seemed ok. After some googling came up with a command line, but it just displays "color lcd" and no panel number...



  • mvanier Level 1 Level 1 (0 points)

    I've posted on this list before, where I suggested that a big part of the eyestrain problem is the blue light-dominated spectrum of LED backlights.  It turns out that I was completely wrong.  Sure, the spectrum may have some unpleasant effects, but (for me, at least) it isn't the major factor.  What happened was that I got a new MacBook Pro about a week ago.  I knew that the built-in screen was likely to cause me eyestrain, but I was prepared for that.  I have an old CCFL-backlit Apple Cinema Display on my desktop that I know doesn't cause eyestrain since I've been using it for the past five years with no problems.  It's still fine with my old (early 2008) MacBook.  But as soon as I plugged my new MacBook into it, I got fairly severe eyestrain symptoms right away.  Furthermore, I also got the same symptoms if I plugged it into an even older VGA monitor (my desk looks like a monitor graveyard :-)) using the miniDisplayPort to VGA adapter that Apple sells.  My point is, if you're like me (and I think many of you are), then the monitor simply isn't the problem!  The problem is in the pixels, specifically in a very rapid and random flickering of the pixels that happens on new Macs but not on older ones.  I've also seen this on iPads but not on iPhones (I have an iPhone 4S which I can look at all day, though the light is more blue than I would like).  I think the problem has to be in the video card/driver combination, but this isn't something you can change on a MacBook.  My current plan is to get Linux dual-booted on the Mac and see if that makes any difference.  On Linux you can install open-source video drivers and alter them to your heart's content.  If the problem is due to temporal dithering (one big possibility) it may be possible to turn it off.  Or maybe something else is going on.  I thought that maybe there might be some kind of pixel-level PWM used to control brightness levels, but that seems rather far-fetched.  One thing I would like to know: have those of you who have had eyestrain problems on new Macs had similar problems on new Windows laptops?

  • dmendel Level 1 Level 1 (0 points)

    mvanier wrote:




    The problem is in the pixels, specifically in a very rapid and random flickering of the pixels that happens on new Macs but not on older ones.  I've also seen this on iPads but not on iPhones (I have an iPhone 4S which I can look at all day, though the light is more blue than I would like).  I think the problem has to be in the video card/driver combination, but this isn't something you can change on a MacBook. 




    Any idea what this would mean for Mac Mini? I returned a late-2013 iMac because of severe eye strain/nausea/fuzzy-headedness (by the way it took almost 2 and half weeks  before the symptoms I was experiencing completely went away). I was planning to buy a Mac Mini and a monitor that would not have these effects.

  • mvanier Level 1 Level 1 (0 points)

    Well, I guess I've saved you some money :-)  Seriously, I very strongly suspect that a new Mac Mini hooked up to an OK monitor (even CCFL-backlit) would still show these problems because it still has the Apple graphics drivers.  That would be a good test to make, though, so go ahead and get the Mac Mini, but be ready to return it and please report it to this mailing list.


    By the way, I do believe that manufacturers are listening to us, even if Apple hasn't been particularly helpful yet (though we can always hope).  Both Dell and Eizo have new monitors that are mostly PWM-free (except at low brightness) and Dell is now using GB-LEDs which have a much better color spectrum than traditional white LEDs (I hadn't even heard of this until a couple of weeks ago).  If we can raise awareness of the pixel flickering issue something will be done about it.  If any Apple engineers are reading this, what do you say, guys? :-)

  • mvanier Level 1 Level 1 (0 points)

    Possibly very relevant:



    Apparently, random noise is added to images to improve their grayscale performance (i.e. so that you don't see bands when looking at what is supposed to be a smooth gradient).  This could be what's causing the discomfort we all feel when looking at modern LCD screens.

  • PlotinusVeritas Level 6 Level 6 (14,710 points)

    reduce flicker, and lower brightness and constrast.


    Increasing ambient room brightness helps a lot



    As someone who stares at a monitor 18 hours a day, you dont want your eye strain to end up like this:


    Bad computer eye strain






  • mvanier Level 1 Level 1 (0 points)

    And also this: someone from a Linux mailing list complaining about the exact same thing that bothers me:



    Nobody on the mailing list had a clue what he was talking about (they probably couldn't see it), but he finally fixed it:



    Since this was Linux, this won't work on a Mac, but at least it gives us things to look for.

  • StefanD13 Level 1 Level 1 (0 points)

    Correction to my previous post:


    - eye strain on plasma tv in combination with apple tv: it seems cause was not routing the image through the samsung home cinema, but just the apple tv 3 itself. With apple tv 2 there was no eye strain on plasma tv


    - eye strain using linux: got fixed if using the proprietary nvidia driver rather than the open source nouveau driver. Moreover the proprietary nvidia driver has possibility to configure the dithering (see .html and look for Option "FlatPanelProperties"). I will try more to see whether the options really work. With the nouveau driver I tried as well to disable dithering from the source code but seemed to have had no effect (it could be just faulty nouveau driver).


    - eye strain on DLP beamer with a sony blu ray player: unfortunately I have installed an update on the blu ray player and I have get now burning eyes after less than one hour of watching


    @mvanier: totally agree with you. There was also another guy here who was trying to fix it in linux. Maybe we can start some working group. If we can proove that dithering is the cause, then we can get some credibility and maybe the graphic card makers will start offering the option to turn it off also on other OS than linux.

    I was thinking to buy the following device, by this we could analyze the video (should be lossless capture) and verify the dithering theory. What do you think?

  • mvanier Level 1 Level 1 (0 points)

    @StefanD13: Great news about NVidia driver; I didn't know you could do that!  I'm not sure that "dithering" per se is the problem, though perhaps disabling dithering will remove it.  The "pseudo-random dithering algorithm" described in the link may be the same thing I'm seeing, which looks to me like random snow.  Most sources claim that dithering is most apparent with dark colors, but I see the snow much more strongly with bright colors.  Regardless of terminology, it's great that you're looking into this.  The framegrabber sounds awesome, but I think the data analysis would be challenging (but not impossible).  What I would do is give it e.g. a pure blue screen and see what it represents at the bit level.  I'm really happy to hear that you fixed the eye strain on Linux!  Maybe we can shame Apple into achieving feature parity with Linux :-)  I would love to join your working group.  I also think that if this proves to be the main cause of eyestrain we can put up a petition to Apple.  (Note that this problem is by no means exclusive to Apple, though.)  What I really want to see is an option in the accessibility menu and/or display settings menu to control the dithering and any other flicker-related properties.

  • jza2 Level 1 Level 1 (0 points)

    There is really nothing magical going on here.


    The problem is that many LED-backlit LCDs are specified to use around 200Hz for the carrier wave of the backlight pulse width modulated signal. To avoid headache and sore eyes, a frequency around 20kHz should be used instead. This is because a LED does not have much reminiscence to speak of. For example with an CRT even the most sensitive users were happy with 100Hz because of the relatively long afterglow of the display phosphor. CCFL-backlit LCDs also have some reminiscence.


    You can find the datasheet for a specific LCD by typing its model and the keyword "filetype:pdf" to Google. The website reveals the panel manufacturer and model in their reviews. There is also this YouTube user which has made some PWM measurements from laptops: . Then the website does have backlight measurements for desktop LCDs too.


    There are some ways by which you can measure the backlight frequency of your display. Of course the easiest indicator of a too low frequency is either feeling nauseous or having a headache or sore eyes, or seeing double images when you move your eyes rapidly from left to right. To measure the exact frequency though, you need special equipment. Some methods are 1) measuring the PWM signal from the LVDS connector using an oscilloscope (look for the pin FPWM, INV_PWM or similar), 2) using a system with a light diode routed to an oscilloscope (the light diode is placed against the surface of the LCD), 3) using an ultra high-speed camera to record video footage of the LCD.


    Coming back a bit, Apple should simply use panels which are designed to use a higher frequency. If they realize the importance of the issue, it shouldn't be a too hard thing to fix for the electrical engineers. The company makes premium products and thus this is a characteristic that could be an important factor for their devices.

  • Kxtr73 Level 1 Level 1 (0 points)



    As I know Apple does not apply PWM in backlight anymore.

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