Eye strain from LED backlighting in MacBook Pro

hi dmendel,

with regrets I can tell you that I got myself a Dell U2410F with great hopes (after reading carefully this email thread) and it didn't help me at all. I got the monitor in eBay for about USD250 and the specs -pleny of input connectors- and comments here where looking very appealing -i.e. it doesn't do dithering, 8-bit color, etc.

I've tried the following with the unit:

- Connect my macmini via HDMI port ---> no luck, still same sympthoms, eye strain, diziness, pain... My conclussion was that the inteln HD4000 graphics card was somehow sending a signal to any monitor that will produce the unconfortable eye effect.

- so, I take my very old desktop PC (the one I'm using for work as last resort, 2007 pentium 4 with NVIDIA GeForce FX 5200 and my monitor LG Flatron L1750S) and just hope that by plugging it to the Dell via VGA I'll have at least a big and decent display. To my disappointing, when connecting my known good PC to the Dell U2410, the problems appear!!! Go and explain this... It is not the graphic card, it is not the drivers (windows XP btw) and a combination that works well with an old monitor turns out to don't with the Dell. My conclussion, whatever the GPU card signals to the monitor gets interpreted somehow by its hardware & software (calle it dithering or something else) to the dislike of our eyes.

all in all, I'm back to desperation. There goes 250$ and what is worse the hope and ilusion that this time it will work. Perhaps I didn't have the right settings? I've tried all possible combinations of brigthness, contrast, gamma, color types... with no luck. I must say that aside the non-working-as-expected fiasco, the image quality wasn't that impresive.

Sorry for delivering bad news and by all means keep trying mate! It might be the case that it works for you.

best regards to all,

luis

I think it makes sense to be something in the graphics card, seems like some kind of incorrect synchronization with the monitor? I am not an engineer, but to what else can i say about the experience i describe below.

In my work place i have two monitors: Asus VW193D and Dell P1911. My old Dell desktop was running Win 7, and i had no problem with either monitor for many hours of work. VGA Connection.

Changed the tower with a new HP desktop PC running Win 7, i get terrible headache and eye strain after an hour of work. Specifically with the Dell monitor i get eye strain in just 5 mins. Both displays are CCFL and i use a VGA connection. I wonder if there have been any major changes in the graphics card technology.

Currently I am working only with the Asus display, and only with frequest breaks, which is not convenient especially during periods of job pressure.

I have a Dell U2410 and it's great for my eyes. I would recommend it if you're working on OSX.

kvoth wrote:

I have a Dell U2410 and it's great for my eyes. I would recommend it if you're working on OSX.

What machine are you using it with? Both you are mvanier endorse it, but I am wondering what it is like with new Macs. luisx's experience really has me worried because I am planning to use the new monitor with a 2012 Mac Mini.

dmendel wrote:

kvoth wrote:

I have a Dell U2410 and it's great for my eyes. I would recommend it if you're working on OSX.

What machine are you using it with? Both you are mvanier endorse it, but I am wondering what it is like with new Macs. luisx's experience really has me worried because I am planning to use the new monitor with a 2012 Mac Mini.

2010 (or 2011?) macbook air, and 2013 macbook pro retina.

Kvoth,

It's no good with new macs. I have a new macbook pro that gives me severe eyestrain with the U2410 even though my old Mac Pro does just great with it. This reiterates my point: it isn't the fault of the monitor. It's the graphics card and driver that are responsible for the eyestrain. Talking about monitors (other than known factors like PWM and blue light) is wasting time.

BTW I dual-booted Ubuntu Linux on my Macbook and it also gives me eyestrain (though seemingly less than the Mac). The interesting thing about this is that the Linux kernel with Intel graphics drivers (which is what I'm using) hasn't done temporal dithering since 2011 (they use spatial dithering instead). So even the dithering hypothesis seems to be wrong, though I will look into this more deeply. Because Linux is open source it's possible to really get into the system, which is what you need for a problem like this.

@tfouto: regarding the phototransistor, just calculated based on the rise and fall time of the phototransistor

@mvanier: please don't give up the dithering yet, I just cannot imagine other reason. It may be the driver is still faulty and the code is not working well there. Spatial dithering should be easy to check using this: http://www.lagom.nl/lcd-test/black.php. Should make sure first that under linux really no temporal dithering is used. I think it is worth to change the intel driver to disable the dithering completely and see if there is a change (either with a high speed camera + magnyfiying glass and/or the http://www.lagom.nl/lcd-test/black.php). Should use as well only the embedded panel since external monitors all do dithering as well.

But in general I agree, it is not so probable that perfectly OK external monitor (with dithering) suddenly becomes unusable when just upgrading graphic card or driver, so it may be another reason as well.

mvanier,

it's not wasting time. You have to understand that it's not the same for everybody. In my case is purely the display alone. Not software-graphics-drivers. Display alone. I am sure i am not the only case.

There is a trend here that thinks that it's graphics-drivers alone. It's not. It might be one of the causes, but not the only one, for sure...

btw when you say:

"It's the graphics card and driver that are responsible for the eyestrain. "

What they might produce to cause eyestrain?

tfouto: Sorry, I didn't mean to be inflammatory. I realize that this is a complicated problem and there are a lot of dimensions to it. What I really mean is that we _know_ about PWM and blue light and we can quantify them. The graphics driver stuff seems to be much more mysterious, so it's more frustrating. Also, I don't want people to get the idea that getting a good new monitor will fix their problem, because it very likely won't due to the driver problem.

As for how a driver can cause eyestrain: there are quite a few ways. The most obvious would be to have temporal or spatiotemporal dithering, whereby two colors are flicked back and forth at 60 Hz to simulate a color in between the two. Graphics cards can all do this, and the driver controls whether they do this and how they do this. I thought this was a promising idea, but then I found that the Linux kernel and Intel driver had switched off spatiotemporal dithering in 2011 (because it "made the display look pulse-y", which seemed really promising!). But alas, an up to date Ubuntu installation still causes eyestrain, though perhaps less than a Mac. That means I can look at the display for an hour instead of just ten minutes, which I guess is progress.

One thing I did see in multiple places on Linux mailing lists was that disabling DRI (direct rendering infrastructure) fixed the problem for several people (at the cost of losing hardware acceleration); that's easy to do (if it works at all) and is something I'm going to try next. Also, there is a spiffy package called intel-gpu-tools on Linux whereby you can set register values directly, including those responsible for dithering. This should really help us determine whether dithering is the issue or just one of the issues. Even if disabling DRI on Linux fixes the problem, it's not much help because this doesn't tell us what's really wrong, but at least it would be a starting point. Perhaps we (I) can work with some of the Intel Linux developers to narrow down the cause(s).

hi manvier,

No need to say sorry, was just your opinion.

Have you tried a 120hz monitor? It should help, the same way higher pwm frequencies helps, although it dont fix the issue.

Have you tried on staring at a white screen at a bad configuration? If its pure white, there should not be any dithering, right?

You might also buy and try a usb digital microscope and check if there are pixels flickering.

I dont think there is enough knowloadge of spectrum light on human eyes. There are much unknown information.

Any of you went to an neuro-ophthalmologist? I guess it's more appropriate then a ophthalmologist.

tfouto: In the long run, a 120Hz monitor may be the only solution. I used to be sensitive to CRT screens until I upped the refresh rate to 85 Hz, at which point the problem disappeared. Pure white screens are the worst; conversely, pure black is the best.

I spent a lot of time hacking on Linux today, but with no positive results. The DRI (Direct Rendering Infrastructure) that some people in the past disabled to get relief is now so heavily wired into the Linux graphics stack that it's almost impossible to turn off (when you do, you get a software version that does the same thing). It seems like they are moving towards using openGL 3-d graphics for everything, even for accelerating 2-d graphics that don't need to be accelerated, because it simplifies the software architecture. As far as I know, DRI does very low-level tasks like page flips between two graphics buffers, which shouldn't cause any problem with a static image unless the two pages have different values. This may interact with dithering in a negative way.

Hello,

I'm a long time follower of this thread,

My first problems occured in 2010, with a bad laptop's LG screen , and then, it never stoped.

Before my problems occured, back in 2009, I was used to work with a SZ2XP LED laptop, and play with a PSP with LED screen, with no problem at all.

After my problems occured, with the laptop's LG screen (as everyone here, it traduced with great light persistence, eyesight diminished, as I were still 10/10 on each eye when I went to the Ophtalmologist), I was not able anymore to look at the older LED screens I was used to watch everyday.

Today my desktop computers are all (Work & Home) wired to a CCFL monitor. I'm ok with that.

I don't work anymore with laptop (as they all get a LED screen now).

For the TV, I was used to watch a real 100hz plasma (2008), with no problem.

Recently I bought Full HD TX-P50GT60 plasma, since September, it is straining my eyes more and more. To the point I re-switched to my old real 100hz plasma 😟

So I have a question here :

Do you people here, who have problems with LED monitors, have tried a LED TV ?

Do you get the same symptoms ?

I'm realy tired about buying things that hurt me, and have to return it, or sell it back...

So if some of you can tell me if I can hope to get a decent LED TV without having problems, it would be nice.

I am hoping that the extra view distance of a LED TV compared to a Monitor would make some difference ?

But I'm doubtfull...

Hope we could find a solution for all workers here,

as a software developper, this screens problems are really a difficult barrier to go through

Have a nice day everyone 🙂

Gulien,

I'm curious: how new are your desktop computers? What kind of graphics cards are running on them? And of course, are they running Windows/Linux/Mac OS and which versions? If your problem is just related to monitors, then there has been a lot of progress in the last year or so. I would check out the Dell U2413 monitor; its backlight uses BGr-LEDs which have a much better color spectrum than regular white LEDs and it also doesn't use PWM until you get down to 20% brightness, below which it uses PWM at 8Khz, which should be undetectable by humans. Disclaimer: I haven't tried it myself. There are also monitors coming onto the market that use quantum dots for backlighting, and of course 120Hz + monitors for flicker-sensitive individuals. I understand that a lot of higher-end LED TVs run at more than 120 Hz (I've even heard of 600 Hz), but I have no experience with them.

My Home computer is a Win 7 / Mint 14, I got a 7870 Sapphire graphic card.

My work computer is a Win 7 with intel integrated graphic card.

I got 2 flat CCFL monitors (Acer ...) wich never hurted my eyes (one very old > 2001, and another > 2009).

I've tested many different OS and graphic cards (Win xp, vista, 7, mint, ubuntu, fedora / Integrated graphic cards, nvidia and Amd graphic cards) with these screens, and it never never hurted me.

So ... I've always doubted that dithering, or hardware color management was faultly in the troubles we have.

Maybe the combination of LED + dithering are strengthening the problems BUT, I think the real problems come from LED (or OLED) PWM and blue/white light.

New plasma screen are brighter than before, and they flicker more than before (they were used to have a real 100hz for PAL regions, but today, they got a 3000hz subfield drive which is transmitted to a 50hz refresh rate, absolutely irritating)

By the way, I got a galaxy S3 (OLED), and when I bought it, I was unable to look at it more than 2 minutes.

I followed an advise here, which said to put the "screen mode" to "video", and download the "screen filter" app, to adjust the luminosity, and now, I can stand it for a dailly, not extensive usage. I'm happy with that.

I really would give a try to the screen Dell U2413 you are mentioning.

If I get some courage one day or another to buy it, knowing there is big chances to send it back... I'll give it a try.

I've tested like 10+ LED screens since my problems occured, and I can stand none of them.

Well, I know everybody get different symptoms from differents screens, so my words may sound false for others. I'm just reporting my own experience.

Gulien, thanks for your input! I would like to hear from other people as to whether they've ever had problems with a desktop (not laptop) computer running any OS with a CCFL-backlit monitor. I'm mainly interested in new desktop hardware (say, post-2010) because I know that older desktop hardware works fine with CCFL-backlit monitors (at least in every case I've seen). I remember one person saying that a 2012 Mac Mini with a CCFL-backlit monitor was fine, which surprised me.

Even though I've said that drivers and graphics cards may be the problem in many cases, the thing to remember is that drivers and graphics cards can control many parameters other than just pixels, including brightness and PWM frequency (something I just learned about). It's possible that laptop machines are more likely to try to control PWM frequency (on monitors which use PWM) in the interests of power saving or whatnot than desktop machines, which may just let the monitor choose its preferred settings.

Also, I forgot to mention that there is a new BenQ monitor (the GW2760HS) which is advertised as "flicker-free" and seems to live up to the hype: http://www.tftcentral.co.uk/reviews/benq_gw2760hs.htm. It has _no_ PWM at any brightness level and also doesn't do hardware dithering (pure 8 bit processing, no FRC). Unfortunately it uses standard W-LEDs, but you can't have everything (yet). I hope this catches on, although as far as I can tell you can't get this monitor in the US yet.