Eye strain from LED backlighting in MacBook Pro

CoreLinker, may I know which product that has caused you eye strain? (sorry if you have mentioned that before, I'm too lazy to go back this thread to check..) And have you checked whether it has PWM with the simple method?

The reason I asked that is because the MacBook Airs that MuDaeBoJongShin and I had used both appear to have flicker free LED backlight, and yet we both found them uncomfortable to look at.

I'm now thinking that there maybe things other than the flickering LEDs that are causing the eye strains.

I didn't come here because of problems with Apple hardware, I came across this thread even before I started posting when I was having trouble trying to find a TV which I could comfortably watch.

I didn't find one, and in the meantime have zeroed in on the problem which was plaguing me, the one of flicker. Flicker really is THE element with which I have trouble, be it from CCFLs or LEDs. Flickering backlights have caused me trouble, flicker free ones haven't (so far). Of course, this seems to be different with others.

I came to this thread because I became really interested in researching the problem, and because I am interested in purchasing an iMac. Discussion since I joined has prompted me to spend time at Apple centers whenever I get time, just to be sure. So far, I am still ready to take the plunge. I have an iPad 1 which I love.

I am really interested in what is Apple cooking that is causing you all grief, and is it really Apple's fault or have they done all they can (like fixing the flicker), and if they haven't, what is it that they could do and are they even aware.

Next time I'm at an Apple center I will try a MacBook Air for about 45 minutes (so far I haven't used one for longer than 10 minutes), to see if there is any problem that I can feel.

I tend to agree, given all that has been said on this substantial thread and reading it for the past year etc., that flickering is what causes eye and head strain. Staring into a strobe light isn't natural for your eyes. Your eyes are designed for a steady stream of light (e.g., sunlight and its reflections on objects) and don't prefer 10hz, 40hz, or any other refresh rate that the eye could possibly notice.

I can walk into my cubicle at GE and tell you exactly which CRT monitors are running 60hz, 75hz, and 85hz. I see the flicker. Most people don't, but i can with perfect accuracy, as can other people. Those kind of people I suspect are those who have the head strain (those on this thread), and that logically means we should be looking for a monitor that has 120-240zh (the highest possible), so our eyes won't be sensitive towards it.

TVs have gone that direction, advertising 120hz and 240hz...its everywhere in every store. What I can't figure out is why Apple and PC makers haven't decided to get on board and ditch 60hz on an LCD/LCD-LED panel.

The 60z flickering of flourescent lights ontop your workspace obviously won't help either. Just another bunch of slow wave non-natural strobe lights in front of your face.

The thing is I and many others have discovered a flickerless display isn't quite the cure. There are obviously other properties. Don't forget, most of Apple's lineup is pwm free now. I notice most displays cause various striations, often unique to that display when recorded on camera and that might have some to do with it. I do not think higher rates are a cure, or necessarily healthy. Also you mustn't confuse the refresh rate of the liquid crystal, that doesn't represent flashing or introduce it. You can have a 60 Hz screen which has a backlight refreshing at 200 Hz, that's what matters. The main point of 120 Hz is that it's divisible by 24, which is important for not introducing judder in 24 fps movies and so on.

I think you make the right point. Apple LCD only works well on its native resolution. For a 15" screen, 1680x1060 with such tiny font is not for human eyes. 1440x900 is good, but has to be native, otherwise all fonts are fuzzy out.

CoreLinker: I see! So you're not having problems with the Apple displays. Best wishes to you to feel comfortable with them, really! I think majority of people don't have these problems!

I still have doubt on the MacBook Airs / Pros findings with the simple PWM test method though. I think if a screen is flickering at the khz range (more than a few thousand times per second), it would be quite hard to count the lines with a 1/25s photo..

By the way, what other ways can a LED backlight control its brightness other than using PWM?

As far as I know, LED mainly has only an ON and OFF state and doesn't react reliably by varying the amperage.

Do LEDs generally do that? It sounds extreme. I mean the tech alternatives to pwm aren't hard to come by, just underutilized and sound simpler than kHz ranges.

jaminhubner wrote:

I can walk into my cubicle at GE and tell you exactly which CRT monitors are running 60hz, 75hz, and 85hz. I see the flicker. Most people don't, but i can with perfect accuracy, as can other people. Those kind of people I suspect are those who have the head strain (those on this thread), and that logically means we should be looking for a monitor that has 120-240zh (the highest possible), so our eyes won't be sensitive towards it.

I agree with your logic on the type of people with relatively more sensitive eyes, I can confirm that I too can tell clearly when a CRT is refreshing at a rate lower than 100hz.

But what I don't understand yet is that those un-comfortable MacBook Airs / Pros screens appear to have constant backlight by testing with the simple PWM test method. Even if I were right about the limit of the simple test method (as mentioned in my previous message), those screens are definitely flickering at significantly higher rate than 240hz.

Pixel Eater, I don't know for sure. But that's what I found when I tried to research on this topic.

I think the very first post of this thread has also mentioned this property of the LED.

You know, you could have something. Of course we shouldn't assume the Apples do this unless someone can document it, but I just found a quote, for instance: "At 140 cd / m² in the workplace, we measured a very high switching frequency of 510 Hz, the duty cycle is 67 percent" regarding one Acer S243HLAbmii.

To be honest I'm not handling the Apple Cinema 27 (mini displayport) well, at all! I've recorded it at 240 fps, I've run the line test, it all checks out, but I'm certain now I'm going to have to sell it and try again. Just wondering, does anyone know for sure whether or not iMacs feature the identical panel and light? For some reason I suspect differences. I have heard some people say the 27 alone gives them headaches no other Apple has, but they also sounded like they were just mad matte was out so who knows. Let me disclaim my incompatabilites are extreme and probably unique to me. This display could work very well for other people.

In other news, Pixel Qi has a new 1280 x 800 reflective display coming out maybe in Q2. It's basically the whole e-ink thing, and in some ways is like a Kindle that actually runs at computer speeds with some color, minus the wacky hangups. I think I've already confirmed it suffers severe pwm with the backlight on, owing perhaps to power efficiency goals. They kind of evolved out of OLPC. My harebrained scheme revolves more around never having it on anyway, because really it's one of the best reflective panels to date. As it's just 10.1 inches, if it and I really click I'd like to come up with a multi-panel arrangement just for something to escape to when backlights are kicking my ***, which is most of the time now.

Try this: http://stereopsis.com/flux/

It puts a virtual amber filter over your screen (works with Mac and jailbroken iPhones and iPads) that blocks blue light. You can set the severity of the filter and tell it to not turn off during the day. It's simple to try so try it, heck try anything once. Someone was mentioning the blue LED as the source of the problem, this should help if that's the case.

same problem with my poor eyesight

Here is what I came up with after spending 4 hours playing with options for safari which is what i use most

Copy following code and save it in some .css file ( for ex. safaricolor.css). Then go to safari - preferences - advanced , select style sheet and click on other. Here select the .css file (safaricolor.css in my case). and see how your colors look. You can play with different background colors of your choice just change B5B5B5 with whatever color code you want. Hope this helps good luck.

@media screen,projection,tv {

P, a, abbr, acronym, article, aside, b, bdi, big,

colgroup, command, dd, dfn, dir, div, dl, dt, em, embed,

blink, blockquote, body, canvas, caption, center, cite, code, col,

span, h6, h6 a, h6 a b, h6 abbr, h6 center, h6 span, header, hgroup,

strong, sub, summary, sup, table, td, textarea, th, time, tr, tt, u,

ul, var, xmp {

background-color: #B5B5B5 ! important;

}

}

I posted in this thread some months ago in regard to my returning a new Macbook Pro due to the discomfort caused by looking at the display. I decided to upgrade my 2008 model, which is much more comfortable to use in my opinion (no hard drive clicking, easier to read the fonts, can use screen without eyestrain, etc.), but I'm starting grad school soon, and I think that I'm going to have to take a new computer with me. I am rather torn. I've always really liked my Apple products, and I believe that Macbooks are very well built machines. I think I'm going to try another Macbook Pro and hope that something like the f.lux program might make it easier for my eyes. I've also heard some say (on other forums) that the screens on the new Pros are better. Is this true in anyone's experience? Also, does this seem to be a problem with every one of the new LED models...or is anyone here able to use some of the new ones without discomfort? I am very baffled by this problem. The Pros that I tried about a year ago caused instant headaches and eye strain. Besides the harsh bright coloring, I thought that the viewing angles were unsatisfactory for $3000 laptop. I also felt like I couldn't easily focus my eyes anywhere on the display (I don't really know how else to explain this). Has anyone found that they can comfortably use LED PC screens? If so, that would give me hope that perhaps Apple will move to a more comfortable display. If this is just an inherent problem of LED technology, then I guess I'll have to either get used to it or else buy an external CCFL monitor.

I don't think you can get used to something like this. You can only go blind, which I wouldn't recommend. ;)

I wouldn't buy ANY laptop without giving it a loooooooong trial first, or making sure I could return it without any problems.

I haven't heard of people being kicked out of an Apple Store because they stayed there too long, if there is one in your vicinity you can go there and park yourself in front of the laptop.

f.lux would only work in case it is the blue light which is causing problems. I was hoping at least someone would try it and report back.

Actually I've been using F.lux fulltime CoreLinker, so thanks so much for posting it. There's also an iPhone version, but its problem is there's just like 4 settings for the effect and none of them are much less than overkill. I've moved from the Apple Cinema to the also flickerless, also LED HP ZR2740W. Somehow it's far easier on my eyes. I really wish I could quanitfy it. I'll never use a shiny display again, even though the anti-glare is on the sparkly side.