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 Gurm42,

    Gurm42 Gurm42 May 16, 2013 8:58 AM in response to Neshill
    Level 1 (8 points)
    May 16, 2013 8:58 AM in response to Neshill

    Neshill,

     

    Yes we're aware of f.lux and it helps some people but for many this problem is irrespective of screen temperature and has more to do with the actual technology in play.

     

    Cheers!

  • by Jessiah1,

    Jessiah1 Jessiah1 May 16, 2013 9:02 AM in response to Gurm42
    Level 1 (0 points)
    May 16, 2013 9:02 AM in response to Gurm42

    Yes, and to also be clear a software program cannot actually change the spectrum of backlighting. It can modify the appearance however if the backlighting is LED than the actual light is still very high blue spectrum light.

  • by Jessiah1,

    Jessiah1 Jessiah1 May 16, 2013 9:03 AM in response to Gareth Jones6
    Level 1 (0 points)
    May 16, 2013 9:03 AM in response to Gareth Jones6

    Gareth, I sent an e-mail to Apple referencing this exact post and have not received a response....

  • by David Turnough,

    David Turnough David Turnough May 16, 2013 9:10 AM in response to Gurm42
    Level 1 (0 points)
    May 16, 2013 9:10 AM in response to Gurm42

    Gurm,

     

    Thanks. It feels odd that I should be pleased that other people suffer too. I am the only one in my circle of friends who has noticed this issue, which ended up in me going for an eye test. The only upside to that was that I had a spring in my step leaving the opticians being told that my vision was 6/5 (what's that 20/15 ish?) and I have no requirement for glasses.

     

    A mate at work just asked "Dave, how do I send e-mails on this thing",  upon helping him set up his Sony Xperia SP, which is a TFT, my eyes feel like they are walking different directions. My original HTC Desire was the model with the AMOLED screen, which I don't recall any problems with, but all new phones I've seen with AMOLED screens have been the worst offenders. There really isn't a rhyme or reason, it's hard to map a single technology, screen type which is the main culprit. So a website, whilst only anecdotal evidence, may well help track down or help sufferers.

  • by Gurm42,

    Gurm42 Gurm42 May 16, 2013 9:13 AM in response to Jessiah1
    Level 1 (8 points)
    May 16, 2013 9:13 AM in response to Jessiah1

    Jessiah,

     

    There are two forces at play here:

     

    1. Apple has a strict policy of ignoring these forums completely. Even if what was reported here was "the new Macbook case actively reaches out and stabs people with a switchblade" it wouldn't get any response at all from Apple. I'm not being a hater, they just don't have the staffing to deal with these forums effectively so their official policy is to disregard them.

    2. Apple doesn't much care about us. Now I am being a BIT of a hater, but bear with me. Apple has always catered to those who think their brand is cool, and not to anyone else. It's like the recent Abercrombie and Fitch CEO's admission that he doesn't really want fat uncool people to wear his clothing... in the same way, Apple doesn't want to change up their technology based on customer feedback. They want to tell us what we should be using, not the other way around. They would rather lose a certain percentage of users than change their designs. And although there are hundreds of us on here, that's a drop in the bucket compared to the vast majority of Apple users who think that retina displays are a gift from the heavens.

     

    Ok, I'm done being a hater now. Maybe - the optimist in me says - Apple will listen and stop using terrible blue LED's and revert their screens back to the way they were in 2010. Unlikely, though.

  • by Gurm42,

    Gurm42 Gurm42 May 16, 2013 9:32 AM in response to David Turnough
    Level 1 (8 points)
    May 16, 2013 9:32 AM in response to David Turnough

    David,

     

    I was the only one at my office (200+ people) that had this problem. I gave up Macbook after Macbook to people - to the point where they laughed at me. But then a couple other people saw what I meant - it didn't make their eyes hurt, but I showed them what I was seeing and they SAW it. I felt vindicated.

     

    At first, I too went for a battery of eye tests, and even ended up having to recover from some occupational eyestrain (which is NO FUN, let me tell you). It turns out there has been no remarkable change to my prescription other than a very gradual need for reading glasses or computer glasses (40 and work in IT? Yep, it's that time!).

     

    But yes, other brands are going this way. I get INSTANT discomfort with Apple screens, but Samsung laptops, some Lenovos, some Dells ... are all going this way. I have to believe it's either the backlight OR some intrinsic technology unrelated to the LCD - maybe temporal dithering? I just don't know - that's at play here.

     

    I do know that other things bother me more than most - high intensity LED billboard signs outside of stores, the lights in my office at work - so I'm just always going to be more sensitive to suboptimal light than others.

  • by Gurm42,

    Gurm42 Gurm42 May 16, 2013 9:35 AM in response to Gurm42
    Level 1 (8 points)
    May 16, 2013 9:35 AM in response to Gurm42

    Jessiah1,

     

    I'd love to hear details of the blue-blocker. I don't know that it would help with Macbooks, since the problem there seems to be more focus-related, but it would make many other brands usable for me! I've taken to wearing Gunnar Optics glasses (which have a yellow tint and mitigate blue light) at work to cut the blue from the high intensity fluorescents, maybe this is similar?

  • by Jessiah1,

    Jessiah1 Jessiah1 May 16, 2013 9:42 AM in response to Gurm42
    Level 1 (0 points)
    May 16, 2013 9:42 AM in response to Gurm42

    I believe the focus related issue could be caused by PWM for you, some people are more sensitive to the fact that our devices are essentially strobbing at us to control dimming and power consumption. The anti-reflective part of the coating helps me with fluorescent lights that use PWM however the LED are 10 times worse due to the fact they can power off to 0% power without leaving any "ghost light" behind, therefore the focus issue is from your eyes constantly trying to adapt to changing light. The issue is two fold: PWM + brighter more intense blue light(Harmful blue light in some cases to the retina) so you need some to reflect the flicker and filter the blue spectrum. I myself get extreme migraine, Vertigo and dizziness from these lighting issues.

     

    The coating has not made it to market yet and is in its pilot phase, I will update when I know more about that.

  • by Jessiah1,

    Jessiah1 Jessiah1 May 16, 2013 10:13 AM in response to Gurm42
    Level 1 (0 points)
    May 16, 2013 10:13 AM in response to Gurm42

    An Apple forum moderator just removed my post, looks like they have time to delete information posted here. I am sure they are watching this forum post daily if not hourly, the back light issue is a tremendous issue for the entire world and could end up costing crazy amounts of money for manufacturers to make right if ever there was a product recall.

     

    <Edited by Host>

  • by Gurm42,

    Gurm42 Gurm42 May 16, 2013 10:10 AM in response to Jessiah1
    Level 1 (8 points)
    May 16, 2013 10:10 AM in response to Jessiah1

    Jessiah1,

     

    That does make sense. I don't have PWM issues - or at least nowhere near as bad - with older units. All LED-backlit units use PWM, but I suspect they've just made it "better" (read: worse) recently.

     

    But you're correct - full intensity is both too bright and terribly blue.

     

    I suspect this problem is easily resolvable with better technology. This tech is cheaper and more efficient, thus fueling its widespread adoption. LED's last longer than CCFL panels or incandescent lights, and use less energy... I wonder if anyone ever even bothered to safety test them?

  • by Gurm42,

    Gurm42 Gurm42 May 16, 2013 10:11 AM in response to Jessiah1
    Level 1 (8 points)
    May 16, 2013 10:11 AM in response to Jessiah1

    ARE YOU KIDDING ME?

     

    Seriously, the moderators don't chime in or care when dozens of us are having massive health problems, but the minute someone suggests contacting the government we're censored?

     

    I don't usually get angry but unless someone cares to clarify we have to assume this is REALLY BAD.

  • by Jessiah1,

    Jessiah1 Jessiah1 May 16, 2013 11:59 AM in response to Gurm42
    Level 1 (0 points)
    May 16, 2013 11:59 AM in response to Gurm42

    I don't recall having any issues either until a few years ago. One thing I am questioning is when did PWM controllers become popular and when did 5000K lighting become popular? I think we can trace it back to when I first started having issues, most likely the old lighting from my childhood didn't bother me because it had none of these factors, both of which have more to do with saving energy than anything else. I believe people think blue light is closer to daylight however it is not, when our entire world is blue light we are all going to regret it and wish we had our old yellow florescent lamps back!

  • by Jessiah1,

    Jessiah1 Jessiah1 May 16, 2013 12:10 PM in response to Jessiah1
    Level 1 (0 points)
    May 16, 2013 12:10 PM in response to Jessiah1

    They edited my above post to remove my reference to the government office of CPSC as well, its interesting they are so worried about that. I am actually amused there is someone following me around worrying about what I have to say and getting paid to filter the information. Well sir, I am not going anywhere and I promise to become much more difficult if you continue to edit, delete or censor the information I am sharing here on this forum. I don't know if you noticed but there are 207000 views of this post!!!! It's an issue that will not go away and is going to get bigger as there is more exposure to LED technology in our everyday lives Censoring me will not accomplish anything. What bothers me most about this is that in my direct e-mail to YOU APPLE, I offered to help understand the issue and wanted to discuss it with your company. I believe there are people who can work together to fix this technology for all to enjoy:

     

    OFF THE PODIUM

  • by Jessiah1,

    Jessiah1 Jessiah1 May 16, 2013 12:19 PM in response to Gurm42
    Level 1 (0 points)
    May 16, 2013 12:19 PM in response to Gurm42

    Gurm, Apple is deleting all of my posts 1 at a time

     

    I plan to help as many people as I can when I get this completely sorted out, you may see everything I have posted disapear but I will be working on this and hopefully get more info out there when I have made some more progress.

     

    <Email Edited by Host>

  • by Gurm42,

    Gurm42 Gurm42 May 16, 2013 12:47 PM in response to Jessiah1
    Level 1 (8 points)
    May 16, 2013 12:47 PM in response to Jessiah1

    Intriguing - looks like emails get gakked, which makes sense...

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