Surface Pro & Pro 2 Eye Strain

[maxx7]

Hi

I know this might be a futile attempt, but please read:

I've now used the Suface Pro since December. I've had this problem with new LED backlit displays which use Pulse Width Moduluation (PWM) for dimming the backlight. This means, that the backlight is actually not dimmed, but is flashed on and off with typically 180-600 Hz, but some manufacturers use even 8000 Hz. This causes eye strain and the SP2 does have this flicker also. This is cheaper to do this way, as when the LED is actually dimmed, it will change the color temperature and cause problems in the color accuracy.

I have been able to change all my displays and televisions to such models, that do not use PWM at all, or do not use it at 100 % brightness.
The PWM frequency is measured by sites like TFTCentral and Prad.de in monitor reviews. Manufacturers like Eizo and Benq are advertizing flicker free displays - meaning, this starts to be a recognized problem. There are articles in mainstream media on how to reduce eye strain from working at a computer etc.

But since I do not have PWM in any of my devices (except Suface Pro 2), my eye strain and red eyes have completely disappeared. I enjoyed about a years time of no eye strain, no matter how much I used my computers or SmartPhone (Galaxy S2)

Now when I purchased the SP2, the eye strain came back. I always have dry and kind of swollen feeling eyes in the morning, if I have been using the SP2 for 2 to 3 hours in the evening. When I don't use it for a couple of days, my eyes are problem free.

I know that many people think that it is because of the small text, the PPI of the screen or bad eyesight. I don't wan to go any deeper into that discussion, but it's not. I is the flickering of the display. Mind you, it's a flicker that most people, myself including, cannot detect visually, but the optic nerve does, which causes the irritation. This is a widely recognized problem with several forum discussion even at Apple forums.

So why I'm writing this? It's because I have not been able to find out the PWM fequency of SP2. The flicker is not detectable via the DSLR test but is visible if filming the screen at 25 frames per second with a shutter speed of 4000. Flicker is not present in any of the other displays that I use, by these tests or by the tests that have been done with professional oscilloscopes or similar. It would be beneficial to know the frequency and if the might be something to do about it, e.g. at display driver level.

I also would like to address this problem, because there are cleary people who do get eye strain from SP2 and the problem would be so easy to fix - just do not use PWM, use some other non-flickering technology in the backlight dimming.


I've been thinking of how to convey this issue to Microsoft and try to ensure that the next verson of SP does have a non-flickering display, but I do not think it is an easy task.

Has anyone else experienced eye strain with heavy usage of SP or SP2?

 

[the_new_normal]

I do get eye strain, but difficult to identify the source. It could in part be due to the sp2; but the office I work in has just had a refit, it's now very bright and I use 3 monitors.
Most likely a combination of factors I suppose.

I see you did find a way around the issue, albeit needing to have screen at 100% Surface Pro 2 screen flicker / blinking - Microsoft Community

I also see you also subsequently returned the device Returned my Surface Pro 2 due to screen flicker - Microsoft Community

Not an issue I was aware of, so thanks for bringing it to my attention. Will be interesting to see how this develops.

 

[benjitek]

[BLAH BLAH BLAH]...I've now used the Surface Pro since December...[BLAH BLAH BLAH]

According to your posting elsewhere, you returned your SP in December. So, which is it? You've 'used it since December' or you returned it then?

 

[sharpuser]

Flickering or strobing can be due to interference between the CFL or fluorescent ambient lighting and your computing device. This is similar to the 'strobe' from capturing video with cameras which make a television or computer screen appear to flicker or distort. Incandescent and halogen lighting, which use a continuous 'burn' rather than a strobe from alternating current, should not have this effect.

So, any claims of eye strain from screen flicker or strobing must be investigated using the SP away from CFL or fluorescent lighting. Any video or film footage documenting said claims will not be acceptable, either.

 

[javispedro]

It's probable the eye strain is caused by reflections on the screen (it's extremely glossy) more than any high frequency flicker.

 

[sharpuser]

It's probable the eye strain is caused by reflections on the screen (it's extremely glossy) more than any high frequency flicker.

Agreed.e
Seems if the OP has discovered a legitimate inherent defect with the SP, it would be well known and widely criticized by now. :|

 

[GoodBytes]

LCD back light using a PWM, is a serious issue for many people. It is a topic that very few knows (basically some people that are affected by it knows about it).
A lot of time, people that that claim to have difficulty looking at a screen (but not a paper at similar distance and text size), or have headaches alter prolong usage, is due that they are sensitive to PWM controlled backlight.


What is PWM controlled backlight?
PWM, or Pulse Width Modulation, is a system used to control the back light intensive of a CFL or LED lights. It flickers the lights of the display on and off, at a rapid frequency rate. Faster the flickering, the brighter the screen. The slower the flickering, the dimmer the screen gets. Obviously, max brightness is full ON. The flickering is not something that you see or notice. But you feel it. Basically, your eyes can detect it, but your brain does work to smooth the image out. Now, TECHNICALLY speaking, the PWM flickering is so high that it SHOULD not do any problem, but for unknown reason, it does to some people. For me, I can feel it, but I don't have a any problem. This is probably because I was born with CRT days monitors, and I was using a computer a lot when I was a kid so my brain got used to it. I hate LED Christmas lights. I see, especially if I move, the flickering. It's annoying when going to a friend place or do shopping during the session. But oh well, what can you do. At home I use the old incandescent lights. I am all for LED's, but it must not use a PWM. It doesn't help that the frequency on those are usually very low, as well.

Why is used? And is there a better technology?
It used as a cost saving system. The implementation of a PWM controlled back light is dirt cheap. That is why you see it on all budget class and med to low range consumer grade monitors. There is an alternative technology, however: a dimmer circuit. A dimmer circuit is much more costly and consume more power. You can find computer monitors with dimmer circuit on the high-end consumer grade monitor range. For example, the Dell UltraSharp U2413, a 24inch true 8-bit AH-IPS 1920x1200. Costs 550$ U.S/Canadian. But no flickering! (http://www.tftcentral.co.uk/reviews/dell_u2413.htm). Actually I lie, it does use one, but only at 20% brightness and bellow at: 8750Hz... soooo.. quite high, and unlikely to be a problem. And that is IF you use the monitor at 20% or bellow. I believe they added this, for better dynamic contrast ratio results. So normally no.

Luckily, for those sensitive, Dell knows about the issue, and have implemented dimmer circuit on their more budget monitors, like the Dell P2414H, a 24inch 1080p 6-bit IPS panel. A 350$ monitor. A bit pricey for what you get, but at least it's a pretty darn good monitor (low back light bleeding, fairly decent (for consumer grade) back light uniformity, nice set of inputs, fully adjustable stand, solid stand, good quality, and non glossy panel and monitor body, and a solid 3 year warranty with 6 or mode dead pixel and 1 or more bright or stuck pixel coverage, with no zones or distance policies (this is extremely competitive at the consumer level, especially considering that Dell pays shipping both sides, and you get to keep the monitor while the replacement arrives, with no holds on your credit card or anything like that).
http://www.tftcentral.co.uk/reviews/dell_p2414h.htm (no PWM at all)

You said CFL back light uses a PWM. I don't sense any flickering?
Excellent remark. CFL 'light bulb' (tubes) have a phosphor layer in the 'light bulb' (tubes) to retain light between the cannon firing inside. High-end CFLs uses a thick and high quality phosphor which retain light very well. But, low end CFL's found on budget monitors, won't do a good job at retaining light, making people sensitive to it, see it.

Also, high-end CFLs outputs a nice rich white colors, which is a big issue for LED back light where the "white" light, is a very cold white. Of course, which the grade of the LED, the better the white. The ideal solution, is RGB-LED, which is perfect red, green and blue LEDs, put very very close together, to output a white light, of course using a dimmer circuit. Sadly, RGB-LED is extremely expensive technology, and hence found only on select professional grade monitors. The cheaper version of it, is GB-LED, which the Dell U2413 mentioned above uses, which is green and blue LED put very close together, with a layer of red phosphor on top to output the light. The downside of this technology, is in order to make it affordable (yes, despite the price of the monitor), it's not high grades LED's, and the lack of red, makes the backlight output a green white'ish color. Not too bad, just a tint. But probably an issue for professionals who needs color accuracy.

With CRTs, you had a bit of the same story. Cheapo CRT that everyone got, because they didn't know any better, could only 60Hz-75Hz at its native resolution, and uses low quality phosphor layer inside the tube. That is why it was a flickering madness thing. However, high end CRT's not only didn't do static as you brought your finger on the class (has no relation to this, but I just wanted to mention it), but could go to higher frequency such as 85Hz-150Hz. But also used high grade phosphor layer which reduced significantly the flickering, to be non visible for the great majority of people. Although, due to the lack of Internet back then, and less people having computers, and also less people using the higher end CRTs, it is hard to say if the problem was eliminated, or was truly better, but it should be on paper.

I hope the above give you a brief overview to everyone and understanding maxx7, problem that he faces, and know more about monitors in general.

IMPORTANT NOTE
It must be noted however, what what sharpcolorado suggested, is also correct. If the area you are in uses cheapo CFL, or a broken transformer, the reflective nature of the display of the device, might show this flickering, confusing you in thinking it's the display of the SP2, when it's the room light(s) the issue.

So, to answer maxx7 question.
I don't know for sure. I don't have the equipment to measure. However, one of the the reason why I got the Surface Pro 2, is the fact that I don't SEE the flickering. So either it's super ridiculously fast, or it doesn't use a PWM, but rather a dimmer circuit. So that means, no problem for me.

However, having used the more the Surface Pro 2, and I see it uses a hybrid system. ~30% or less it uses a PWM at high frequency, and anything above that switches to the dimmer circuit. I noticed that by playing with the brightness leveler in Windows 8 under Setting on the charm bar. Where if you slide up and down continuously and slowly the level, jumping from ~30% to 100%, you can see that the backlight dims in and out smoothly. As soon as you drop down to ~30%, you can see that there is a slight stepping as the brightness adjusts, indicating a PWM. And, under specific condition with the screen, and room light, I can see the flickering at anything bellow ~30%. But never been a problem, above that. As Microsoft seam to use a dimmer circuit, it suggests that the switch to PWM on the fly bellow ~30% is to save power, and not cheaping out (as both systems are implemented). But that is my guess. We can't ignore the fact that perhaps the LED's doesn't go as low as Microsoft would want, and this is a way around it, but regardless its a power saving feature.

Again, I have not measured this, and this is based on my personal observation, and what I am sensing.
I hope this helps.

 

[maxx7]

LCD back light using a PWM, is a serious issue for many people. It is a topic that very few knows (basically some people that are affected by it knows about it).
A lot of time, people that that claim to have difficulty looking at a screen (but not a paper at similar distance and text size), or have headaches alter prolong usage, is due that they are sensitive to PWM controlled backlight.


What is PWM controlled backlight?
PWM, or Pulse Width Modulation, is a system used to control the back light intensive of a CFL or LED lights. It flickers the lights of the display on and off, at a rapid frequency rate. Faster the flickering, the brighter the screen. The slower the flickering, the dimmer the screen gets. Obviously, max brightness is full ON. The flickering is not something that you see or notice. But you feel it. Basically, your eyes can detect it, but your brain does work to smooth the image out. Now, TECHNICALLY speaking, the PWM flickering is so high that it SHOULD not do any problem, but for unknown reason, it does to some people. For me, I can feel it, but I don't have a any problem. This is probably because I was born with CRT days monitors, and I was using a computer a lot when I was a kid so my brain got used to it. I hate LED Christmas lights. I see, especially if I move, the flickering. It's annoying when going to a friend place or do shopping during the session. But oh well, what can you do. At home I use the old incandescent lights. I am all for LED's, but it must not use a PWM. It doesn't help that the frequency on those are usually very low, as well.

Why is used? And is there a better technology?
It used as a cost saving system. The implementation of a PWM controlled back light is dirt cheap. That is why you see it on all budget class and med to low range consumer grade monitors. There is an alternative technology, however: a dimmer circuit. A dimmer circuit is much more costly and consume more power. You can find computer monitors with dimmer circuit on the high-end consumer grade monitor range. For example, the Dell UltraSharp U2413, a 24inch true 8-bit AH-IPS 1920x1200. Costs 550$ U.S/Canadian. But no flickering! (http://www.tftcentral.co.uk/reviews/dell_u2413.htm). Actually I lie, it does use one, but only at 20% brightness and bellow at: 8750Hz... soooo.. quite high, and unlikely to be a problem. And that is IF you use the monitor at 20% or bellow. I believe they added this, for better dynamic contrast ratio results. So normally no.

Luckily, for those sensitive, Dell knows about the issue, and have implemented dimmer circuit on their more budget monitors, like the Dell P2414H, a 24inch 1080p 6-bit IPS panel. A 350$ monitor. A bit pricey for what you get, but at least it's a pretty darn good monitor (low back light bleeding, fairly decent (for consumer grade) back light uniformity, nice set of inputs, fully adjustable stand, solid stand, good quality, and non glossy panel and monitor body, and a solid 3 year warranty with 6 or mode dead pixel and 1 or more bright or stuck pixel coverage, with no zones or distance policies (this is extremely competitive at the consumer level, especially considering that Dell pays shipping both sides, and you get to keep the monitor while the replacement arrives, with no holds on your credit card or anything like that).
http://www.tftcentral.co.uk/reviews/dell_p2414h.htm (no PWM at all)

You said CFL back light uses a PWM. I don't sense any flickering?
Excellent remark. CFL 'light bulb' (tubes) have a phosphor layer in the 'light bulb' (tubes) to retain light between the cannon firing inside. High-end CFLs uses a thick and high quality phosphor which retain light very well. But, low end CFL's found on budget monitors, won't do a good job at retaining light, making people sensitive to it, see it.

Also, high-end CFLs outputs a nice rich white colors, which is a big issue for LED back light where the "white" light, is a very cold white. Of course, which the grade of the LED, the better the white. The ideal solution, is RGB-LED, which is perfect red, green and blue LEDs, put very very close together, to output a white light, of course using a dimmer circuit. Sadly, RGB-LED is extremely expensive technology, and hence found only on select professional grade monitors. The cheaper version of it, is GB-LED, which the Dell U2413 mentioned above uses, which is green and blue LED put very close together, with a layer of red phosphor on top to output the light. The downside of this technology, is in order to make it affordable (yes, despite the price of the monitor), it's not high grades LED's, and the lack of red, makes the backlight output a green white'ish color. Not too bad, just a tint. But probably an issue for professionals who needs color accuracy.

With CRTs, you had a bit of the same story. Cheapo CRT that everyone got, because they didn't know any better, could only 60Hz-75Hz at its native resolution, and uses low quality phosphor layer inside the tube. That is why it was a flickering madness thing. However, high end CRT's not only didn't do static as you brought your finger on the class (has no relation to this, but I just wanted to mention it), but could go to higher frequency such as 85Hz-150Hz. But also used high grade phosphor layer which reduced significantly the flickering, to be non visible for the great majority of people. Although, due to the lack of Internet back then, and less people having computers, and also less people using the higher end CRTs, it is hard to say if the problem was eliminated, or was truly better, but it should be on paper.

I hope the above give you a brief overview to everyone and understanding maxx7, problem that he faces, and know more about monitors in general.

IMPORTANT NOTE
It must be noted however, what what sharpcolorado suggested, is also correct. If the area you are in uses cheapo CFL, or a broken transformer, the reflective nature of the display of the device, might show this flickering, confusing you in thinking it's the display of the SP2, when it's the room light(s) the issue.

So, to answer maxx7 question.
I don't know for sure. I don't have the equipment to measure. However, one of the the reason why I got the Surface Pro 2, is the fact that I don't SEE the flickering. So either it's super ridiculously fast, or it doesn't use a PWM, but rather a dimmer circuit. So that means, no problem for me.

However, having used the more the Surface Pro 2, and I see it uses a hybrid system. ~30% or less it uses a PWM at high frequency, and anything above that switches to the dimmer circuit. I noticed that by playing with the brightness leveler in Windows 8 under Setting on the charm bar. Where if you slide up and down continuously and slowly the level, jumping from ~30% to 100%, you can see that the backlight dims in and out smoothly. As soon as you drop down to ~30%, you can see that there is a slight stepping as the brightness adjusts, indicating a PWM. And, under specific condition with the screen, and room light, I can see the flickering at anything bellow ~30%. But never been a problem, above that. As Microsoft seam to use a dimmer circuit, it suggests that the switch to PWM on the fly bellow ~30% is to save power, and not cheaping out (as both systems are implemented). But that is my guess. We can't ignore the fact that perhaps the LED's doesn't go as low as Microsoft would want, and this is a way around it, but regardless its a power saving feature.

Again, I have not measured this, and this is based on my personal observation, and what I am sensing.
I hope this helps.

Thanks, this is a good wrap up of PWM.
I do have to wonder, why people who do not understand a subject, are quick to comment a solution that they "think" is the problem, without having any facts or understanding the issue.

The flicker in a fluorescent light setting is a different issue. Surface Pro 2 does have a PWM at some high frequency, which cannot be measured by DSLR. The screen flickers in a dark room as well. Now, as said, this is not detectable flicker.

I've now used my SP2 for about 8 months. I cannot use it at all, if the backlight is anything but 100%. if I turn it 90%, my eyes start to strain in 15 minutes. I've tested this like a hundred times, so this is an absolute fact. I've also tested this in various places, dark, outdoors, different types of lighting. So this is an absolute non disputable fact, that it does have flicker when the backlight is not 100%

I do have the HP display, which does not flicker under any circumstances. That also does not cause any kind of eye strain, no matter how much I use it. (The same goes with SP2 when 100%)

SP2 is not very useful device, when the backlight is 100%. The battery drains in less than an hour sometimes, so I need to keep it connected to the charger most of the time, when I use it, so it is essentially not a table, but a small desktop computer.

So now I'm considering buying the SP3, since I do like the small size and the weight, when travelling. This is why it would be quite nice to know, whether it does have the same PWM/flicker as SP2.

Please do read and understand what GoodBytes wrote about PWM and try to refrain from commenting anything ignorant like "dry eyes, use eyedrops" or "it's the reflections from the glossy screen" -these have absolutely nothing to do with the PWM problem that some people suffer.

Also, I do believe that even for those people who do not get any noticeable problems from the PWM, it is still harmful in the long run. Nothing scientific, but it just cannot be healthy staring a flickering strobe light 8 h a day, when such a flicker is nowhere to be seen in the nature. Some people's eyes or nerves could be resistant to the flicker, but it means that some system in the body is fighting against it and is constantly stressed out, even if you cannot notice it.

 

[maxx7]

According to your posting elsewhere, you returned your SP in December. So, which is it? You've 'used it since December' or you returned it then?

The point of this is not to legally prove that I have a Surface Pro 2. I did return it, but bought another one at a discount afterwards.

 

[javispedro]

Please do read and understand what GoodBytes wrote about PWM and try to refrain from commenting anything ignorant like "dry eyes, use eyedrops" or "it's the reflections from the glossy screen" -these have absolutely nothing to do with the PWM problem that some people suffer.

Please try to refrain from calling other comments "ignorant", then.

For a largest majority of people all of the eye strain _will_ be caused by reflections. I completely disagree with stuff like:

A lot of time, people that that claim to have difficulty looking at a screen (but not a paper at similar distance and text size), or have headaches alter prolong usage, is due that they are sensitive to PWM controlled backlight.

That is outright false. Please provide empirical proof. Don't say "in your experience", because, "in my experience", it's reflections.
Otherwise all you're doing is encouraging "collective obsessional behavior".

If you find and quote some empirical A/B testing on a variety of people then we might all learn something.

I am not saying that _all_ people are insensitive to high frequency strobes. I am in one of those areas where classic lightbulbs were forbidden decades ago and we saw some real cases of this stuff. Been there, seen that.

 

[maxx7]

Please try to refrain from calling other comments "ignorant", then.

So are you saying that it is not ignorant to suggest that people who do suffer from the PWM effect, should use eye drops, when that suggestion is based on lack of knowledge, that there really are people who suffer from such a problem?

A bit like I'd say that you are from Madrid, though it says in your profile that you are from Barcelona. Would my comment be the opposite of ignorant then? Or less severely, less not ignorant?

Why I requested that the ignorant comments would be kept to a minimum, is exactly the fact that in most of the discussions related to this problem, 80 % of the comments are suggestions that are ignorant to the fact that there is a real problem which will not be resolved by eye drops or eating fish oil. It always distracts the conversation when the majority of commenters are talking about an entirely different problem.

Yes, I am a bit harsh, but it really is frustrating to have these discussions with people who claim there is no such problem. The goal should be to spread the information of the problem, so at some point more manufacturers would recognize the problem and stop using PWM in displays.

And for the other comment, yes, I do think that in many cases the problem is the PWM. Yes, I do not have scientific peer reviewed double blind evidence, but neither did Einstein have, when he came up theories of space and time. You have to be able to point out new ideas without having peer reviewed double blind studies to prove it.

The advertising of eye drops has really increased a lot. I do not believe that suddenly there are just more people suffering from dry eyes, because of its 2014. There is a reason for that and I suggest that the most likely reason is that people use smartphones and new LED LCD displays a lot more than previously, and the PWM in those displays is causing a problem, which people seek to remedy with eye drops, when they do not realize that the displays are actually causing the problem. Now people have been using displays since the eighties at work and at home, but only during the last couple of years LED or AMOLED displays with PWM have spread wide, in correlation with eye drop commercials, whichs were almost nonexistent 10 years ago, at least where I live. If they advertise, people must also use those more. It's not like the pharmaceutical companies suddenly decided that let's try to sell more eye drops to people by advertising more.

Again, not scientific, peer reviewed, double blind. But this is a good starting point for such a study, which I hope would yield some useful information which in turn would get more manufacturers on board to the non PWM displays.

 

[maxx7]

Also you do not either have peer reviewed data that general populations eye soreness is NOT due to PWM, so you are quite wrong saying that my comment is outright false, when it well might be true.

If I pointed out that "I think there might be some person in this world that has sore eyes due to PWM and tries to use eye drops to remedy it" is not useful.

Whereas if I say "I think many people suffer the effects of PWM without knowing it" might spark someone to investigate and see, whether my opinion is correct.