I've now yet again tested 3 laptops. Matebook X Pro 2020. PWM at some 60 % brightness. Zenbook S U3939, no PWM and Dell XPS 9300. None of these are OK. All cause significant eye strain. Not like PWM, which gets my eyes bloodshot in 30 minutes, but if I use a full workday, my eyes are reddish and watery. Next morning my eyes feel like the lids would be sand paper. So it seems that temporal dithering must be the cause. I've had several laptops over the years which cause no eye strain at all, like Lenovo x280 and some other lenovo's. They all had PWM, but not at 100% brightness, so I was fine if I just set them at full brightness. Same with many phones. OLEDs cause immediata blood shot eyes. I've had many where there is PWM, but only on lower brighness levels, so I just make sure I disable the auto brightness and use them at levels where there is no PWM. But there have been phones with no PWM, Like some Huawei's and Xiaomi's which still have caused severe eye strain. But those have had better color reproduction, so I suppose this means FRC or temporal dithering. Now I'm thinking of getting a native 10bit desktop display to confirm that temporal dithering or FRC is the problem. My thinking is that it is the pixel flickering that is my issue among PWM flickering and then if a display is native 10 bit, there would not be any pixel flickering like temporal dithering. Would anyone who is more knowledgeable in these, care to comment if this might make sense? For me it is not Windows version or driver related, since those laptops and desktop monitors that don't cause eye strain, I have always used the newest Windows versions and drivers. Then of course, if there happens to be a laptop with 10bit screen, I would be interested to try it, almost no matter the cost of it, since really, I need to have a laptop due to my work, but now it starts to look like there simply are no new ones. I may have to start hoarding old Lenovo's with poor displays to be future proof for a few years. But what then - some day those will just be too old and I need to get a laptop with the modern display tech, which I simply cannot use. Well, I can, I don't get migraines, but it is really irritating to have bloodshot eyes constantly and use eye drops to compensate the dryness, the dryness which is only caused by the flicker. And anyway, there are number of forums discussing this problem. How can it be that we make no progress?

I would also like to understand why some Android phones are completely OK, not causing any eye strain and some are not. With phones it seems to be PWM related, so that if there is a PWM, it is OK when used in the brightness level where there is no PWM. But all Phones that I have tried, that do not have PWM, will cause eye strain. How come there is nobody from the actual display industry participating in these discussions. There must be someone who has this problem and knows the actual technology. There are so many places around the net where people are discussing this that it is clear that this problem is not that rare anymore. Though I see one of the problems being the fact that many of these discussions end up discussing food supplements or other health issues, giving outsiders the impression that it is a vague issue that comes and goes and would have some placebo components in it. For me it is totally binary without anything circumstancial or vague. If there is flickering in a display, it irritates, if not, it does not irritate. I also find it a bit annoying that sites like Notebookcheck keep pressing the disinformation that frequencies over 500 hz would not cause a problem. I've had several phones with a PWM of some 2500 Hz and it is without doubt irritating my eyes. If I use the phones with brightness level where there is no PWM, I will have zero irritation even if I would use the screen for 12h a day. My optic nerves are able to sense a flicker of 2500Hz. I could show this in a blind test any day easily as people would be able to observe my eyes turning bloodshot by the 2500Hz flicker.

Maxx How come there is nobody from the actual display industry participating in these discussions. There must be someone who has this problem and knows the actual technology. We had a Microsoft employee (that someone tried to bring here to investigate alleged Windows 10 display issues and a few other things), but he seems to have gotten lost as COVID got worse. Maxx I also find it a bit annoying that sites like Notebookcheck keep pressing the disinformation that frequencies over 500 hz would not cause a problem I do agree that generalized statements like that are harmful. The closest to empirical data I've seen here was an old "lighting industry" paper that claimed certain "strobe" effects rapidly dropped off after a few KHz. Again old paper, and I'm not sure of the methodology used.

It would be nice to meet a person with similar situation than mine. Most of the time people seem to have all kinds of other issues which kinda obscures the situation. I've had the PWM sensitivity for more than 25 yeas, so most likely since birth, or at least since puberty. I don't have any other health issues or any other rare issues. It is just the flicker that causes my eyes to go red. Though related item is that my eyes turn bloodshot by even moderate alcohol use. This of course happens to many others, but my case my eyes get so red even after a few beers that people start commenting my red eyes. So my eyes do get red easily, but with a flicker free monitor I have zero problems no matter how much I use the monitor.

Has anyone had any success with g-sync or freesync laptops?

Maxx I think g-sync in the case of laptops means the screen has no PWM by default, but a) those are often "bulky" gaming laptops, and b) "Other" software issues can still come into play.

Maxx of the time people seem to have all kinds of other issues which kinda obscures the situation I think part of the issue is you get triggered by one source (PWM), then if you don't improve your situation, your condition gets worse over time.

@JTL Disagree totally. Like I wrote, I've had this for more than 25 years and particulary some 15 years ago, when I had no idea what was causing it, except for that the cause is a computer monitor, I was using PWM monitors constantly and my eyes were constantly bloodshot and very irritated, but once I learned about PWM and was able to get a PWM free monitor, the problem disappeared completely. It is just in recent years that manufactureres have started to utilize the FRC/Temporal dithering with many screens that also cause flicker, this problem has come back. But always when I find a device without Temporal Dithering and use it with brightness levels where there is no PWM, the problem disappears. The thing is that it does not seem to be possible to eliminate the flicker anymore with most devices. Even if there is no PWM, there is Temporal dithering and there is no way to remove that. Programs like Ditherig or Iris do not help at all.

There is nothing mystical abou this problem. It is very much like excercising muscles. If you excercise too much, your muscles will get sore, but when you stop it, they will heal. Similarly, as the optic nerve senses the flicker it will get strained and strain the muscles in the eye, which cause the bloodshot eyes, but when you stop doing what causes it, then the muscles / nerves heal.

I think the issue is that not everyone is affected by PWM, Muscle strain wouldnt be immediate, a 'bad' screen device will affect me almost immediately I have a CCFL monitor that has PWM and I used it for 11ish years with no problems, I didnt know what PWM was! I had an OLED samsung S6 phone, had PWM was fine untill I dropped it 🙁 Then I got other devices with PWM and they were not fine, then I got other devices that dont have PWM and they were not fine, I've returned motorola phones with and without pwm and laptops without PWM but they still caused problems The only consistent thing for me is that devices that are using technology up to around -2018 are OK, newer items are NOT ok for me. - my newest OK device is an Ipad from 2018 but I have to use reduce white point. There are some exceptions though but I think this is firmware related OR I have irreversably damaged myself Anyway - how can we tell if we have a 10 bit screen? I would also like to hoard old lenvo machines as I've had success with them although one died on me recently.

I have now tested 5 laptops in a few weeks: Matebook X Pro 2020 - LCD pwm at 60%, used at higher brightness but still caused some eye strain after several hours of use, not usable for work purposes as it would require daily 10 h usage. Asus Zenbook UX393 - LCD without PWM, but causing much more eye strain than Matebook, probably Temporal dithering? Dell XPS 9300 - LCD with PWM at 25%, but used at higher brightness, similar to one above, might be a bit less eye strain, but still difficult for work usage Lenovo Legion 5 Pro - LCD witout PWM, Nvidia 3060 discrete, 165Hz refresh rate. Seems to not cause eye strain, at least not that bad. I have to try it a couple of more days at work. Suspected cause of not causing eye strain is Nvidia discrete graphics and 165 Hz refresh rate. Asus Zenbook Flip U371 - OLED with PWM below 52 %, 60 Hz slight lowring of brightness above 52%, similar to PWM, but does not seem to cause major eye strain. I will still keep testing.. Suspected reason of not causing eye strain: 10bit OLED without FRC / Temporal dithering and lack of actual PWM above 52%. The slight eye strain that seem to feel might be due to the 60Hz slight banding above 52%, but will it be a problem after using 10h on consecutive days, remains to be seen. @HAL9000 there are very few actual 10bit screens in the market, none for laptops that I know of. Mostly high end photo editing screens. I was also able to use CCFL screens with PWM (at least some of those) with minor eye strain. That is because CCFL dims and lights up slowly, so the flicker is not as abrubpt as with LED and OLED. I personally think that the newer devices are problematic as manufacturers are squeezing more colors out of lower quality panels with Temporal dithring / FRC. Now why this does not seem to be the case with the Lenovo Nvidia combo is that I disabled the integrated GPU from the bios and use only Nvidia GPU, which might have different type of dithering or no dithering at all. But who knows. The problem with the non PWM screens causing eye strain is that the eye strain is not immediat like with PWM. it requires several hours of usage. So often times I might think that the screen is OK, but after the second workday where I've used the screen for 8 h or so, I see my eyes being bloodshot. This is similar to CCFL PWM. if ai was gaming every night for several hours, my eyes started to get strained and bloodshot in a couple of days. This does not happen with my HP ZR40w27 display that does not have PWM. (some 8 years old) or e.g. with Surface Pro 2 at full brighness. Or with Sony televisions without PWM. Even if I would have strained eyes from PWM, I can rest my eyes using the HP display or a sony TV.

Laptop for those with PWM and flickering sensitivity

JTL

Maxx Yes, this is clear, the spectrum favors blue light. But the blue light from a screen is 1 and the blue light from the blue sky is 100 or more. So even if the spectrum favors blue, I don't buy the idea that it would irritate the eyes.

I've personally seen flicker free blue LEDs on certain electronics of bright intensity, and it's not very pleasant to look at.

I don't buy that even in the case of a flicker-free display with no dithering that "everything is entirely fine, move along", hence the drive for more research.

Or what if a person is in a room painted blue lit by blue light. I don't think there would be any eye strain

I mean, this kind of brings back an earlier point of mine. CRT monitors had a more even spectrum compared to "modern" WLED backlights, and I don't recall people obsessing over color temperatures with those.

I think that in most cases they have just mixed flicker with blue light as the flicker is something (temporal dithering) that cannot be [measured].

Could you detail your rig how you video temporal ditering?

There are still many unknowns with the dithering problem, one being that the display outputs on a laptop versus the connection used for the internal LCD do differ, so it's not trivial to reliably detect dithering on a laptop as using the internal LCD.

I haven't written up all my notes and testing, but here's some info on my project "VideoDiff"

https://ledstrain.org/d/848-project-videodiff
https://wiki.ledstrain.org/docs/appendix/tests/dithering/

Maxx

@JTL Yes, I agree that staring at a blue light for hours every day might not be good for eye or sleep health. So I agree that the lightspectrum should be as close to natural sunlight as possible.

But does the blue light spike in the spectrum actually cause any significant eye strain? Not at least for me and presumably to most people, since most people do not experience any eye strain from any screen, even with PWM or Temporal Dithering.

So that's why I argue that the marketing BS about blue light is misleading as it tries to connect blue light to eye strain, while most people do not experience any eye strain with screens. Those who do, the cause is most of the time PWM or dithering.

Maxx

I was thinking if the dithering could be detected by purchasing a cheap microscope and filming that with a dlsr or even mobile phone.

jen

JTL I once read a paper from the "lighting industry" that claim that some of the effects of PWM persist up to around 10KHz, but I'm not entirely sure of the methodology involved.

This may have been a reference to this 2011 paper by Bullough et al. where 20% of people could still notice the stroboscopic effect of flicker at 10,000Hz. They did not test higher frequencies, so did not determine at what frequency no one can detect flicker. http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.876.126&rep=rep1&type=pdf

Phip

hi, i use the razer studio 2020, with the quadro 5000, older driver, but the screen is pwm free, one of the very few. maybe test it as it works for me really well.

Quad43

Phip which drivers?

Phip

Quad43

use linux

Maxx

@Phip Is it the OLED version - that surely cannot be PWM free?
Are you in the same situation that PWM AND temporal dithering is a problem?

Phip

Maxx

Yes OLED and the only PWM free screen on market I think. I tested it seems to be correct. And feels great to use.

Maxx

Just realized that my HP ZR2740w is a 10 bit (8+2 FRC) so Temporal dithering? I don't know. But this monitor has given me zero eye strain for the past 10 years no matter how much I used it and with what kind of hardware.

The only thing I can think of is that I have some 5 years old Nvidia 970 card - maybe that then did not yet have the technology that the newer ones have, which is producing the eye strain in more recent laptops?

Oh what a frustrating problem this is. I may need to start hoarding old Lenovos to be able to work eye strain free when not at home.

Maxx

So a bit an addition to the above - now I'm quite baffled on why the HP display is completely eye strain free, as it DOES have temporal dithering.

What can be the cause, since it is not Windows version, using Ubuntu or different display adapters?

What gives? What could be the source of irritation in all of the laptop displays, since PWM is overruled and the Desktop HP monitor does not give eye strain even though it has temporal dithering?

How can this be so difficult to find out what gives the eye strain apart from PWM?

Could it be the way the FRC is implemented? It does not seem to be the latency of the panel, since the HP panel is quite fast and can be used for gaming.

Does anyone have any idea?

Seagull

Maxx

Have a search on the forum for LCD inversion.

Maxx

There are tens of threats when I search. Any chance someone could tell what it is and what might be the assumptions so I would not need to spent hours investigating this?

Sunspark

Maxx No, because there is no one singular cause that applies to every individual.

Maxx

Could you please try to re-evaluate your position. If LCD inversion is a problem, there needs to be similarities as to why it is a problem for those affected. Saying it is individual, just does not make any sense.

If we keep cultivating the idea in this forum that displays cause completely random issues for every individual, there is absolutely no hope to find any kind of solution and we could as well stop the discussion.

We need to try to be more scientific to this problem and have some categories on the source of problem like:

PWM is absolutely and scientifically confirmed to be a problem for some. Reason: flickering light irritates the eyes, because the optic nerve senses the flicker, even if we are unable to actually see the flicker.

LCD inversion is a problem for some. Reason:? (flicker also?)

FPS games are a problem for some. Reason: unnaturally fast action without actual movement cause motion sickness, similarly like in sea sickness there is the opposite, movement without perception of movement. (in sea sickness gazing to the horizon helps, as then the brain also sees the movement that is felt by the body)

Temporal Dithering - now I'm unsure whether it is so simple anymore. Like I wrote earlier, the HP display that has been problem free for the past 10 years, does have temporal dithering. So maybe it is a certain way the Dithering is implemented, that produces the eye strain...

but please, do not give the impression that this is a completely individual problem where everybody has a different reason why they can't use a certain display. This cannot be the case. We just have not been scientific enough in our testing and do not seem to have adequate understanding of the technologies, nor eye physiology.

Abeabe

Phip Oled does not use pwm but it flickers too, and to me is worse than pwm.

Kabz85

Hi @Maxx, one question, do you get symptoms with screen that have high frequency PWM, like for example 5000 HZ ?

Aquila

Au Optronics panels or Innolux are the best choice.

Avoid BOE.

In fact I need to sell my Zephyrus G15 boe panel, It's flicker free and it hurts my eyes.

All Au Optronics choices are good for my eyes.

eyestrainsolutions

Aquila

Aquila How do you know what laptops have Au Optronics screen? Thanks

Aquila

Abeabe I don't trust in oled flicker free. It's marketing as LG OLED TV certified flicker free by Tuv Rheinland, but all of these have flickering (watching by Phone Camera)

Aquila

eyestrainsolutions check it with hwinfo app

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