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 jasonfromsanantonio,

    jasonfromsanantonio jasonfromsanantonio Dec 9, 2008 6:58 PM in response to Torrance Hodgson
    Level 1 (0 points)
    Dec 9, 2008 6:58 PM in response to Torrance Hodgson
    Interesting, I wear glasses and have an astigmatism.

    I am still trying to get used to the MacBook Aluminum display and its still giving me problems. I have tried using inverse colors and its not helping.

    Last days to return are upon me and unfortunately it looks like I will be taking this machine back for the MacBook White. Its a bummer because I am really digging the sturdy and machined feel of the aluminum.
  • by afteshock_68,

    afteshock_68 afteshock_68 Dec 10, 2008 3:39 PM in response to RMartin111
    Level 1 (0 points)
    Dec 10, 2008 3:39 PM in response to RMartin111
    Hmmm, I wonder what the effect of polarized glasses would do to this display?

    They seem to help against reflection.
  • by gpzbc,

    gpzbc gpzbc Dec 10, 2008 4:46 PM in response to afteshock_68
    Level 1 (0 points)
    Dec 10, 2008 4:46 PM in response to afteshock_68
    True polarized lenses would keep you from seeing your screen except at weird angles.

    ...Speaking of sunglasses, I have been trying out something else. I have been wearing sunglasses when on my laptop. And I keep it at the brightest setting. So far, the eye strain has gone away.
    So I am wondering if it is the extreme brightness that is causing my headaches or if it is the LED at lower brightness settings? Or perhaps both?
  • by sukiyaki,

    sukiyaki sukiyaki Dec 13, 2008 12:04 AM in response to RMartin111
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    Dec 13, 2008 12:04 AM in response to RMartin111
    Same here, I get a lot of eye strain due to the flickering. Looks like the problem is prevalent in the new LED type screen MBs. Did anyone get the problem fixed by Apple - genius bar?
  • by Thomas Artner,

    Thomas Artner Thomas Artner Dec 13, 2008 6:10 AM in response to sukiyaki
    Level 1 (0 points)
    Dec 13, 2008 6:10 AM in response to sukiyaki
    I also think so, that the eye strain and headache comes from a terrible flickering (or pulsating?!) screen technology built in at least the new macBook Air and macBook Pro. I worked with both products a little time and I felt bad after it.

    http://www.csse.uwa.edu.au/~lucas/background.html
    This testpattern is shown rock solid on my old MacBook Pro. On the new ones, its flickering. The picture is not as good as on my old MBP.
    I think the new screens are even worse than the old gen screens. They are just brighter - but thats all.
  • by necronym,

    necronym necronym Dec 13, 2008 6:33 AM in response to noelsmart
    Level 4 (1,410 points)
    Apple Watch
    Dec 13, 2008 6:33 AM in response to noelsmart
    My MBP 2.53 screen hasn't caused me any issues (that I'm aware of) but perhaps the people suffering are actually being overly sensitive to the 'dithering' the screen uses to fool you into thinking your seeing millions of colours instead of the native 262K colours the screen actually displays.

    Apple do not publicly release the bit depth of their displays (this posting will get removed now) as confirmed by their technical support department on 2 separate occasions.

    The price they (Apple) charge for their portables, all of them should have 8-bit displays with no dithering, then people may not be suffering
  • by domdx,

    domdx domdx Dec 13, 2008 12:08 PM in response to necronym
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    Dec 13, 2008 12:08 PM in response to necronym
    Some advice

    Always try and break up the periods you spend looking at the screen into 15 min intervals and have a few minutes between staring into the distance.

    Have an eye exam just in case you have a need for spectacles ,maybe just for computer use.

    You can have an anti reflection coating on your spectacles to help reduce glare.

    Also look at position of screen eg;you tend to blink less (eyes will dry out more frequently) when looking straight ahead compared to when your gaze is at a downward angle.

    Just some tips from an optometrist of 25 yrs experience

    Dominic
    Editor
    www.laser-eye-surgery-review.com
  • by gpzbc,

    gpzbc gpzbc Dec 13, 2008 2:53 PM in response to Thomas Artner
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    Dec 13, 2008 2:53 PM in response to Thomas Artner
    I agree. I don't think the eye strain is from the glossy screen because I still get it in settings with no glare.
    Plus I just did that test pattern and my screen jumps all over the place. And it doesn't move at all on monitor #2 of my dual monitor set-up.

    I think it is simply the fact that it is LED.
  • by Thomas Artner,

    Thomas Artner Thomas Artner Dec 13, 2008 6:46 PM in response to gpzbc
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    Dec 13, 2008 6:46 PM in response to gpzbc
    I've tried the test pattern on an early 2008 macbook pro (also LED backlit) and there the test pattern is not flickering.
    So the problem is not the LED backlight itself...
  • by jasonfromsanantonio,

    jasonfromsanantonio jasonfromsanantonio Dec 16, 2008 5:42 AM in response to RMartin111
    Level 1 (0 points)
    Dec 16, 2008 5:42 AM in response to RMartin111
    UPDATE:
    I went to exchange my aluminum for a white this past saturday. At the apple store they were very courteous (was within 14 days) and had no issue with the exchange. They did mention that the 10% restocking fee would be waived as the exchange was for medical reasons (eyes hurting). After going through the whole exchange process, it occurred to the Apple rep that they had just received screen overlays for the 13 macbooks, a brand new item. Long story short, I left the store with my Aluminum, a screen overlay, and a new 14 day return period to try out the overlay.
    I haven't put the overlay on yet but I'm being optimistic that it will help. Will post update when I find out.
    For those interested, its an 'anti glare film' made by a company called Power Support. Its available at Apple for $34.
  • by gpzbc,

    gpzbc gpzbc Jan 7, 2009 4:58 PM in response to jasonfromsanantonio
    Level 1 (0 points)
    Jan 7, 2009 4:58 PM in response to jasonfromsanantonio
    For all of you doubters out there. I replaced my LED screen for a non-LED screen and the eye strain headaches were gone instantly. 100% gone!
    No doubt about it.
  • by Laurence Casey,

    Laurence Casey Laurence Casey Mar 26, 2009 9:41 AM in response to gpzbc
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    Mar 26, 2009 9:41 AM in response to gpzbc
    This is an interesting thread. I received my new MBP 17 w/ glossy screen 2 days ago and immediately noticed eye strain and sickness. Nothing major, but not normal. At first I suspected it was due to the screen being too bright. So instinctually, I turned it down. Didn't help. So after reading just the first post, I tried tuning the screen all the way up giving the dithering effect a chance as the resolution.

    1. OMG, the screen is bright.
    2. By the time I got the end of this thread, my eyes don't hurt. (keeping fingers crossed)

    I did try the 2 different screen tested as mentioned later in the threads and both of them. The first one which the lines should be lined up with each other, are not. I have a distinct line down the middle.

    The second test to see if the screen flickers, it does all the time. Not bad, but it does.

    3. Since I also do graphic and photography, I had a monitor calibrator. Performing a calibration did not do much to reduce the bright white. Since I work in both Windows and OS X, I am stuck using the same color temperature which has more blue.

    Not sure what to do at this point. I agree that the glare is contributing to the problem and a screen overlay similar to the iphone anti-glare may help. Although, I can see this being a total pain to put on without air bubbles or dust.

    I will contacting Apple Support to see about swapping out for a matte display unfortunately.

    --Larry
  • by gpzbc,

    gpzbc gpzbc Jul 2, 2009 6:35 PM in response to noelsmart
    Level 1 (0 points)
    Jul 2, 2009 6:35 PM in response to noelsmart
    I just want to emphasize that I traded in my LED glossy screen for a non-LED glossy screen. My eye strain headaches were gone instantly and I have never seen them since despite the fact that I am still using a glossy screen.

    Oh, and by the way, I went to the eye doctor recently and my eyes are approximately the same as they have always been.

    There is no doubt that LED was giving me a miserable headache. Perhaps it was me and not all users will have the same reaction. But, with that being said, I would urge all to take caution with the new LED screens.
  • by upriver,

    upriver upriver Jul 2, 2009 8:51 PM in response to gpzbc
    Level 1 (0 points)
    Jul 2, 2009 8:51 PM in response to gpzbc
    Thanks gpzbc. I have posted my experience with the MBP on another thread (http://discussions.apple.com/thread.jspa?threadID=1852329&start=120&tstart=0 Posted: Jun 27, 2009 5:03 PM). Agree that the problem seems to be the LED backlighting.

    Ironically I was really worried about the glossy screen on the MBP prior to purchasing. In the end however I actually quite like the glossy screen, it's just the backlighting that makes me ill. Unfortunately all Mac laptops now have LED backlighting.
  • by cyvi937,

    cyvi937 cyvi937 Jul 2, 2009 11:50 PM in response to upriver
    Level 1 (100 points)
    Jul 2, 2009 11:50 PM in response to upriver
    The white MacBook isn't LED backlit according to the Apple Store comparison table.
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