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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
This is interesting. I recently spent intensive amounts of time in front of my MBP while working on my Thesis. I noticed by the end of the day, I had to boost the zoom on the document to 150% at times as everything was blurry. I believe that most of this was related by time. I tend to keep display lighting at full. But I do notice things get blurry even under shorter times.

I even went to the eye doctor... he said I was simply in front of the computer for too long of periods and due to my age, my eye was not rebounding as quickly for distance viewing. So I've tried to decrease the length of time and balance it with breaks.

Cletus/
MBP 2.16 GHz C2D, 2GB RAM, 160HD
I think the fact they have sold millions and you are the first to post this, it isn't blinding the masses. If you use it at home a lot spring for an external monitor which might relieve things.
I have the same problem. I just got a new Macbook pro 15" two weeks ago. I never had a macbook before, and was used to work for hours with different notebooks (with different kind of linux flavors). After one hour my eyes start to hurt, first I thought maybe the fonts are too small, or the backlight too bright. But changing this didn't help. Then i searched the internet, found several people reporting the same issues with the LED backlight.

https://www.csse.uwa.edu.au/~lucas/background.html

this picture is flickering a lot, but not on my 3 year old Benq Notebook....of course it's not always flickering that much as when watching the static background above..but it seems to be still enough to cause pain in the eye.



And no, it has not to do something with my sensitivity, I have shown it to 4 other people, they all noticed this flicker immediately.

I'll bring it to the shop within the next days, but my guess is, that all Macbooks with LED have this fault.
After 2 months with this 17in Macbook Pro, I began to experience bulging headaches...

... I have reverted to limited computer time, with minimum brightness. Even now after 10 min., my eyes feel a confusing ache that is concentrated more to the mid/rear.

This is a huge disappointment, when I consider how much was invested into this machine.
Troy Douthett
I have the same problem with eyes on my new iMac. After about 5 minutes I feel eye strain. Also my 2 years old daughter feels pain in her eyes after a few minutes and she don't want to see new fairy tales.

I am a computer programmer and I have worked on many LCDs and haven't got such a problem.
I can also see flickering during starting iMac when background is white.
I moved to Mac from PC at home and I am very disappointed.

And this is not the only complain. My first iMac had one bad pixel on LCD and in the store at first told me that it is OK. mac policy about it is: if you have less than 15 bad pixels the LCD is OK and they don't replace it. But after many arguments I told told they replaced it to me.

I like all features on my iMac (although I work as a PC programmer) but i don't understand what Apple wanted to say with these "LCDs".
I have the same problem.
I bought brand new macbook pro 2.5 MHz in 2008.06.27. After 30 minutes of work with the macbook pro, my eyes hurt like well. Return MBP to the store.
I have to say (sadly) "I DID NOT SWITCH TO MAC!"
I have the same problem with my new Macbook Pro at work. By the end of the day I have a headache and can't work.

With my old CRT monitor I always had to use high refresh rates to avoid problems, while others had no problem with them. I'd thought that this problem didn't exist with flat screens - at least this page explains the issues.

I turned on my old powerbook and the display is so much better - I can work with that all day.
I am having an identical problem with the new (Late 2008) Macbook. The new displays are glossy and LED-backlit - exactly the same as what the original poster said. I am cranking the brightness all the way up - I'll post up any results I have later.
I tried changing the refresh rate to 85 hz using SwitchResX as detailed in https://discussions.apple.com/message.jspa?messageID=5011552 - I did it late at night, so I was feeling tired already. Woke up this morning - aching after using the display for 20 minutes. Not sure what to do.
Wow! This explains alot!

The very same night i received my MBP, moving from a MB, I woke up with the most intense headache I have ever to experience, I went to the toilet and threw up. Earlier that day I had experienced issues with focusing and contrasts. Needless to say, most of that day had been spent in front of my new MBP. I assumed it was just the brightness, and the next day I readjusted the lighting in my room. To no avail. I succeeded to change all my fluorescent power-saving lightbulbs with incandescent ones, thinking that might be the cause. I actually spent three days popping pain-killers, trying to alleviate the strain on my eyes and the headache.

I know I'm one of those more sensitive to flickering light, but that this would make all of the (now current) laptops from Apple basically very hard for me to use, is quite shocking.
I'm desperately trying to adjust to my new screen, by brute force. I've slightly grown accustomed to it. But it still strains my eyes to such an extent that my work has suffered.

I'm disappointed, and a bit sad, to read this.
I wonder if someone makes a mat finish window tint, anti glare type of film to go over the screen. Or if that would even help. I just ordered a mac book pro. I'm a computer tech that is in front of a screen at least 10 hours a day and I already have eye problems. I'm interrested to see how this will affect me.
I bought a new 15" MBP on November 4, spent the evening migrating, and within 10 minutes of actually using it on the 5th I developed severe motion sickness symptoms. Within 30 minutes my eyes hurt. I tried to work through this and failed absolutely. The MBP was returned to the Apple Store on November 10.

I now no longer have an upgrade path.
I bought a new late-2008 13.3" aluminum Macbook on November 10 and spent several hours using it that afternoon and evening. I immediately noticed that web pages were not as clear and crisp as I was accustomed to, and as the day went on, I began to get a headache and a sensation of queasiness/motion sickness bad enough that I had to stop using the computer. I tried it again the next morning and the headache and queasiness returned after only a few minutes; same experience that night after work. I tried again today after 24+ hours away from it and within just a few minutes, the headache and queasiness returned. I have tried adjusting the brightness as low as it will go, as well as increasing it, and nothing seems to help. I have never had this experience with any display in 20+ years of intense computer usage. So, it looks like I will have to return the Macbook. Does anyone know whether the Macbook Air would be a viable alternative, with its higher-quality display? My understanding is that Macbook Pro has the same LED-backlight technology as the Macbook, plus I need the smaller/lighter form factor. Any advice will be much appreciated. Thanks.

Message was edited by: sdjdguy
I just got my MBP yesterday and I've already spent over an hour on forums trying to find out about this because the problem is so bad for me. It takes less than 5 minutes for a headache to develop. I can perceive the flicker even at maximum brightness when looking at high contrast areas as you described. It is especuially apparent if any sort of animation is high contrast.

I'm giving it a week to see if I get used to it, but if I don't I'm afraid I'm going to have to return my product. I don't want to, I absolutely love everything about this notebook except the headache it gives me. I hope apple addresses this. I'm also very curious to find out what percentage of the population has this problem.

I'd be perfectly willing to pay for an LCD screen to be swapped into this machine if it were available. I wonder if any aftermarket or factory option will address this in the future.

最後更新：2017-08-20 18:54:13

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