RMartin111

Q: Eye strain from LED backlighting in MacBook Pro

There is one relatively serious con of the new LED backlit displays in the new MacBook Pros that seems to not get too much mention in the media. About a month ago I bought a new MacBook Pro to replace my standard white MacBook. One feature of the MacBook Pro that I was unaware of was the introduction of the LED backlit display to replace the CCFL backlight.

Once I started using my new laptop for long periods of time, I noticed severe eye strain and minor symptoms almost similar to motion sickness. After 20 or 30 minutes of use, I felt like I had been looking at the screen all day. Much longer and I would get headaches. If I used the old white MacBook (with its CCFL display), I had no eye troubles at all. Moreover, I could detect a distinct flicker on the MacBook Pro display when I moved my eyes across it - especially over high contract areas of the screen. White text on a black background was virtually impossible for me to read without feeling sick to my stomach because of all the flickering from moving my eyes over the text.

The strangest thing about all of this was that nobody else I showed the screen to could see these flickers I was seeing. I began to question my sanity until I did a little research. Discovering that the MacBook Pro introduced a new LED backlit display started to shed some light (so to speak) on what might be going on. I had long known that I could see LED flicker in things like car taillights and christmas lights that most of my friends could not see. I also knew that I could easily see the "rainbow effect" in DLP televisions that many other people don't see.

My research into LED technology turned up the fact that it is a bit of a technological challenge to dim an LED. Varying the voltage generally doesn't work as they are essentially designed to be either on or off with a fixed brightness. To work around this limitation, designers use a technique called pulse width modulation to mimic the appearance of lower intensity light coming out of the LED. I don't claim to fully understand the concept, but it essentially seems to involve very briefly turning off the LED several times over a given time span. The dimmer the LED needs to appear, the more time it spends in the off state.

Because this all happens so very quickly, the human brain does not interpret the flickers as flickers, rather as simply dimmer light. For most people that is. Some people (myself included) are much more sensitive to these flickers. From what I can tell, the concept is called the "flicker fusion threshold" and is the frequency at which sometime that is actually flickering is interpreted by the human brain as being continuously lit. While the vast majority of people have a threshold that doesn't allow them to see the flicker in dimmed LEDs, some people have a higher threshold that causes them to see the flickering in things like LED car tail lights and, unfortunately, LED backlit displays - leading to this terrible eye strain.

The solution? I now keep my screen turned up to full brightness to eliminate the need for the flicker-inducing pulse width modulation. The screen is very bright, but there are no more flickers and I love my MacBook Pro too much to exchange it for a plain MacBook with CCFL backlighting (which will also supposedly be switching to LED backlighting in 2009 anyway.) The staff at my local Apple store was of course more than helpful and was willing to let me exchange my glossy screen for matte even though I was beyond the 14 day return period. I knew that wasn't the problem though as my old MacBook was a glossy display. I've decided to stick with my full brightness solution. Sitting in a brightly-lit room tends to help alleviate how blinding the full brightness of the screen can be. In a dimly-lit room I guess I just wear sunglasses. Either way, the extreme brightness is worlds better than the sickening flicker I saw with a lower brightness setting

I would caution anybody considering buying a product with an LED backlit display to pay careful attention to make sure you don't have this same sensitivity. Turn the screen brightness down, find a high contract area of the screen, and quickly move your eyes back and forth over the screen. If you can detect the flicker, you may end up with this same problem.

I have no idea what percentage of the population has this sensitivity. I imagine we will hear more about it as more and more displays start using this technology. Hopefully the Apple engineers will come up with a way to eliminate this flicker some of us can see.

Russ Martin

15-inch MacBook Pro, Mac OS X (10.5.4)

Posted on Aug 23, 2008 8:25 AM

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Q: Eye strain from LED backlighting in MacBook Pro

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  • by Me-U-andthe-Forum,

    Me-U-andthe-Forum Me-U-andthe-Forum Nov 20, 2008 7:51 PM in response to RMartin111
    Level 1 (0 points)
    Nov 20, 2008 7:51 PM in response to RMartin111
    I have had my macbook pro pretty for about almost a month now and I have just recently been getting what i know as eye strain headaches from it, and at first it bewildered me but then i thought maybe it was the reflection on the monitor, but after reading this it makes sense and I am thinking I might have to get a different computer.

    For those of you who traded in for another Mac, what did you trade in for? This ***** b/c I LOVE this computer
  • by greene-r74,

    greene-r74 greene-r74 Nov 22, 2008 10:50 AM in response to noelsmart
    Level 1 (5 points)
    Nov 22, 2008 10:50 AM in response to noelsmart
    I stare at screens for 9 hours a day and occasionally get eye strain headaches, but not every day. And I do take frequent breaks in between. But whenever I use my macbook it seems like every time within a half hour or less I start getting headaches.

    I've never used a machine with a LED backlight, I don't know if thats the culprit but it sure seems like it might be. I wish there was a way to measure the flicker. I know if you take a video of a monitor with a digital camera you will see it roll as the lines scan across the screen. This screen looks solid when you take a video of it. I cant detect any visible flicker but I do also experience headaches.
  • by lenn5,

    lenn5 lenn5 Nov 22, 2008 10:52 AM in response to RMartin111
    Level 4 (2,531 points)
    Nov 22, 2008 10:52 AM in response to RMartin111
    I'm curious to find out if you guys having eye strain have the matte or glossy display? I'm going to be getting an early '08 MBP and haven't decided on which display to get.

    thx
    lenn
  • by Stefan Ro.,

    Stefan Ro. Stefan Ro. Nov 23, 2008 3:16 PM in response to RMartin111
    Level 1 (0 points)
    Nov 23, 2008 3:16 PM in response to RMartin111
    hello R Martin,

    I understand what you are talking about, same problem here with the new MBA.
  • by pitchcorrect,

    pitchcorrect pitchcorrect Nov 24, 2008 3:44 AM in response to RMartin111
    Level 1 (0 points)
    Nov 24, 2008 3:44 AM in response to RMartin111
    I used to get eye-strain and had the subtle, yet noticable flicker with my macbook pro 2.4 (early 2008) when brightness wasn't at 100% - my computer suffered from the well-documented dark-lines "curtain effect" led problem..

    Apple replaced my entire screen, and along with it the inverter board (it's built into the screen assembly) and now everything is fine, screen is absolutely rock solid.

    it's probably the same problem - a defective inverter board, probably causing the pulse width modulation driving the LEDS to not cycle consistently.

    I'd suggest to all people that have this problem, have them replace your screen, or at the very least, the inverter board. trust me, it's not the LEDs..
  • by Thomas Artner,

    Thomas Artner Thomas Artner Nov 27, 2008 6:33 AM in response to RMartin111
    Level 1 (0 points)
    Nov 27, 2008 6:33 AM in response to RMartin111
    Hey,

    I've got the same problem here. Working a lot with computer, also with my old macbook pro (without led backlight), I bought a new MBA. Its impossible to work longer than 15-20min at a time without getting some sickness.
    Looking at the MBA screen, and my old MBP screen side by side shows the issue very well. The MBA screen iss much more exhausting than the MBP screen.
    My MBA is going back now...

    Tom.
  • by jasonfromsanantonio,

    jasonfromsanantonio jasonfromsanantonio Dec 2, 2008 8:37 AM in response to RMartin111
    Level 1 (0 points)
    Dec 2, 2008 8:37 AM in response to RMartin111
    I have purchased my first Apple computer this past weekend, a 13" MacBook Aluminum. After the first day of setting it up I noticed my felt strained after an hour or so. I noticed that the auto adjustment of the brightness was rather sensitive to slight light changes, so I disabled that feature hoping for better results. The second day I used the machine, I recognized that my eyes were still uncomfortable. After a couple more days of limited use, I still experienc this discomfort. I was thinking my eyes would get adjusted to the fonts, colors, shading, etc that make up the wonderful interface and the pain would go away. A search of Google has led me here and that the issue may be with the LED backlighting.

    I have worked for years (and continue to do so) on more traditional laptop displays and have never experienced a discomfort like this. I will go talk to a Mac Genius at the local apple store to see if they can recommend anything. I really want to keep the MacBook but if my eyes continue to reject the change, I will have to give up this new beauty.

    Message was edited by: jasonfromsanantonio
  • by gpzbc,

    gpzbc gpzbc Dec 2, 2008 9:51 AM in response to jasonfromsanantonio
    Level 1 (0 points)
    Dec 2, 2008 9:51 AM in response to jasonfromsanantonio
    I am having the exact same problem. I'm not sure what to do because I really don't want to give up my new computer. I keep hoping that I will get used to it.

    Has anyone successfully "gotten used to it"?
  • by jasonfromsanantonio,

    jasonfromsanantonio jasonfromsanantonio Dec 4, 2008 5:23 PM in response to jasonfromsanantonio
    Level 1 (0 points)
    Dec 4, 2008 5:23 PM in response to jasonfromsanantonio
    UPDATE:
    I visited with a Apple Genius today at the NorthStar Mall location in San Antonio, TX. I went through the changes I had tried... Deactivating auto brightness, resolutions, adjusting brightness, and even creating a new color profile under display. He went through routine, 'what are you using the mac for?' 'do you do things differently on your pc laptop?' Indicated that bright whites and such could be causing the problems... I indicated I had been using the mac the same way i do my PC.

    The only other option he suggested was trying the 'inverse' color option (command, option, control and 8 key all held together) and see if cutting down on the amount of bright white helps. I don't think its an acceptable solution but I'll try it occasionally to see if it does any good. He made reference if there was anything wrong with the technology that everybody would be having this problem. Slightly aggravated I will try every option they give me to show that its more than browsing webpages with white backgrounds that's causing the problem.

    At this point I have had my MacBook for 5 days and there is a 14 day return period. I will try a couple more days and if things do not get better, I will return the computer. I believe I will try downgrading to the 'White' MacBook with a matte screen to see if it works better with my eyes. I feel that the quality of the mac product as a whole eclipse the chincy looking and feeling laptops from the PC manufacturers.

    If my eyes automagically adjust to the MacBook aluminum display, I'll be very happy. I'll make updates on what i find. If you have any recommendations, please post them here!
  • by Torrance Hodgson,

    Torrance Hodgson Torrance Hodgson Dec 4, 2008 5:39 PM in response to RMartin111
    Level 1 (5 points)
    Dec 4, 2008 5:39 PM in response to RMartin111
    I thought I'd post here what I posted on a similar thread (http://discussions.apple.com/thread.jspa?messageID=8573649#8573649):

    I was having problems with headaches and eyestrain immediately after getting a new MacBook. But it turns out that it was my eyes and not the screen that was the problem after all: something about the new screens was making my previously unsymptomatic (and undiagnosed) 'astigmatism' become symptomatic. Basically, I could see fine, but my eye muscles were (unconsciously) straining to pull things into focus, and this triggers tension headaches.

    So it won't help those people who were noticing flickering, but if it's just headaches and eye strain, consider getting an eye test.
  • by gpzbc,

    gpzbc gpzbc Dec 4, 2008 5:42 PM in response to Torrance Hodgson
    Level 1 (0 points)
    Dec 4, 2008 5:42 PM in response to Torrance Hodgson
    So which came first, the chicken or the egg?
  • by greene-r74,

    greene-r74 greene-r74 Dec 4, 2008 6:43 PM in response to Torrance Hodgson
    Level 1 (5 points)
    Dec 4, 2008 6:43 PM in response to Torrance Hodgson
    A couple things I've noticed with mine. The first thing is that I don't see the flicker unless I play a few games of Guitar Hero first then use my macbook. Then I REALLY notice the flicker. I thought that was strange. Another thing I notice is that the 1440x900 res makes me strain harder to read the screen. I find myself using the zoom a lot especially if I already have a headache. And thirdly, I tried a pair of Gunnar Optiks gamer glasses. (Had insurance pay for it.) My vision and staring at computers is part of my job. And they do a decent job. They have a slight magnification and they kind of curve your view a little. Like an IMAX theater. There lightly tinted yellow so they block out a litte of the blue light. I find looking at the screen more relaxing. I think most of this issue is eye strain. Turning down the blue tint might help. Calibrate your monitor on the warm side. And none of us are used to having monitors this bright. I've had my macbook for about a month now and I'm not having the headaches that I was when I first got it. I also have my macbook hooked up to a 26 inch Samsung TV and I get headaches from looking at that as well.
  • by Thomas Artner,

    Thomas Artner Thomas Artner Dec 5, 2008 3:34 AM in response to Torrance Hodgson
    Level 1 (0 points)
    Dec 5, 2008 3:34 AM in response to Torrance Hodgson
    Hey,

    the headache comes definitely from the display. I've use a new MacBook Air for about 4 days, and had headache for the last 3 days I used it.
    Then I switched back to my old MacBook Pro, and there was a big difference. It was much more exhausting looking at the MBA than on my old MBP.
    I tried this test pattern: http://att.macrumors.com/attachment.php?attachmentid=143756&d=1226449702 ( you have to zoom in to show it on 1:1 Zoom Level)
    This testpattern was terrible flickering on the new MBA. On my old MacBook Pro and on an other iMac i have the picture was very good. No "jumping", no flickering...

    I guess there is something wrong with some of these displays.
  • by gpzbc,

    gpzbc gpzbc Dec 5, 2008 2:29 PM in response to Thomas Artner
    Level 1 (0 points)
    Dec 5, 2008 2:29 PM in response to Thomas Artner
    Thanks for providing the test pattern. I did it and my screen seems to be just fine. So my eyes just must not work well with the LED.
    Crap! I don't want to send this back for an exchange.
  • by lakeshore,

    lakeshore lakeshore Dec 7, 2008 12:19 PM in response to gpzbc
    Level 2 (295 points)
    Dec 7, 2008 12:19 PM in response to gpzbc
    It's the glass. People may have used glossy screens before, but not glassy. The glass is crystal clear and has no functional or apparent anti-glare coating. The reflections caused by the glass are exponentially stronger than on a regular glossy LCD screen. The reflections alone cause the eye to continually refocus in order to see past them, but this is an illusion caused by the eyes and brain working overtime to disregard them. To compensate for the intense reflections, Apple has tuned the screens to be exceptionally bright. So, yes, it's the brightness of the screens that is causing the headaches, but the reason the screens are so bright is because Apple had to find a way to compensate for the tremendous amount of reflection caused by the glass plate. If you want to avoid headaches altogether, get a computer with a matte screen.
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