Hello everyone,i wanted to share a story about what happend to my vision and i'm, 99% sure that BenQ monitor's cause it but i need to warn you that it might be long read a bit and please forgive me if i made any speling mistakes english is not my main language but i hope you will understand what i want to tell. Ok lets begin. In 2012. i got my first PC from my parents,it was an old PC with Belinea 1705s 17" CCFL TN monitor. I've been upgrading PC often since then but i didn't changed monitor until 2016. For those 4 year of usage i've been having eyestrain,dry eyes and red eyes but nothing serious and it wasn't bothering me that much and it only happend when i've been using PC for like 12 hours or more. What was important to me was to keep my vision good because i had perfect vision i never worn glasses or lenses and i was scared that this monitor could damage my vision because it was old. I then decided i need to buy new monitor and keep my eyes healthy so i ordered BenQ GW2255 VA LED monitor with flicker free technology. When i got that monitor after just a couple minutes of usage i noticed immediately something was wrong,LED light from the monitor was somehow pinching my eyes it was a weird feeling but i tought maybe i just need to get used to it. I continued to use that monitor and because i didn't work anything back than i was playing games all day long. After few months problems have started,first thing i noticed was when i was watching a movie in the dark room with black background and with white letters i could see double it was ghosting. I didn't got scared and i thought maybe it's normal.I continued to use PC normally and i noticed it's getting worse. In the summer off 2017. i started to work at nights driving a taxi. Then the nightmare begin it was the time when i finally realised how much my vison was damaged,it was terrible i had ghosting,starbursting,halos and glare problems but i still could see sharp at distance and close. In the daytime i still have perfect vision but in the night it's terrible. I got really scared and went to ophthalmologist. He did't found anything,my eyes are healthy and i don't need glasses. Then i decided to buy new monitor and get rid off this one and bought brand new BenQ GW2406Z IPS LED Low Blue Light Flicker Free monitor. It didn't help at all it was worse than the other one,i can not stand to watch at it long like i was able to watch in the prevous one or the old Belinea. Since than i went to 4 more ophthalmologist and nothing. I still drive at nights and it's still terrible and it got worse over time but it only get worse when i use that monitor and i have a solid proof. Here it is....about a month ago a had ingrow toenail surgery and i had to be in bed for 5 days for recovery,i coudn't walk so i decided to use my PC for those 5 days,i though what is the worse thing that can happen for only 5 days? I've been playing games and watching movies for those 5 days on GW2406Z and after 5 days when i was recovered i decided to go out at night. I didn't noticed that my vision had changed in the lit room only thing was that my eyes were dry and a bit red but i tought it's normal i had that even with my old Belinea.When i got out i almost had a heart attack,my vision went from bad to terrible,every starbusting and ghosting was 3 times bigger it was a disaster. I got so scared almost started crying. Went to do home to find artificial tears because my eyes were dry and it didn't help at all. Since than my vision hasn't improve at all,dryness disappeard the next morning but my vision never return to what it was before those 5 days. I still drive at night but it's a nightmare now really,i didn't use GW2406z at all since than i only use my old Belinea monitor. Conclusion,i think that those two monitor ruined my eyes (and my life two because i'm 22 years old and i always had only one wish in my life and it is to become truck driver but with vision like this i don't think i will be able to). Also i need to mention that i used BenQ monitors on 0 brightness and they don't flicker i tested it. I hope that someone will read this and maybe figure out how dangerous monitors can be,i'am now really depressed every day when i wake up i have only one wish to somehow fix this issue and return everything to normal,i don't go out anymore at night and i don't play games and i was able to do both before i bought BenQ monitor. I wish that i stayed with my good old Belinea and never bought new monitor things would be so much different now.
My terrible experience with BenQ LED monitors
NightWolf149 Please share your story to lightaware.org. The more they have, the more it will become a real issue.
martin I will.
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NightWolf149 Also i need to mention that i used BenQ monitors on 0 brightness and they don't flicker i tested it.
They probably do flicker. With my current photodiode oscilloscope setup, which isn't even that sophisticated yet, I didn't find obvious on/off PWM but there is a ripple of about 25 kHz on my BenQ monitors, even the newer EW2775ZH, which is not small especially on low brightness.
I have 2 BenQ EW2740L, one is good and one is clearly worse. Both have the 25 kHz ripple but they also have another ripple of ~450 Hz and ~750 Hz. The 750 Hz one is the "good" monitor. I didn't find other differences apart from a different factory color tone which I corrected in the OSD to have roughly the same colors on both monitors. I have no proof yet that the frequency difference is related to the eye strain, but the difference is there, and the displays are not truly "flicker-free".
NightWolf149 Maybe you want to try not using any monitor anymore for a week or so. Not even the Belinea.
KM Well i tried,after those 5 days i haven't been using computer for a full month and it didn't help,maybe it needs more time i don't know but i need to mention that while a i was not using my PC i've been using my phone which also has IPS LED screen and it also makes my eyes hurt. I started using Belinea few days ago. I will try not to use PC or phone for a week but it's really hard because i need phone for my job.
"When i got that monitor after just a couple minutes of usage i noticed immediately something was wrong,LED light from the monitor was somehow pinching my eyes it was a weird feeling but i tought maybe i just need to get used to it."
You described my issue exactly when I look at an LED computer monitor. Pinching eyeballs. I had the same effect on "Flicker-Free" BenQ monitors as well. I'm stuck in the technological stone age in CCFL backlits 
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Well,because off that i bought my self DELL e198wfp which is CCFL and my eyes don't hurt so far but this will not fix my damaged vision.
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I also bought a BenQ LED monitor 2 months ago (24'', VA panel, matte screen).
"Low Blue Light Plus", Flicker Free, with a special chipset... I took some time to test it in all configurations possible, and it does NOT work. After 10 minutes I still have headaches and eye strain.
I should have sent it back to Amazon before the one month limit but I thought I could find some special setting. And I came from an aggressive Dell Inspiron laptop (17'', LED, TN, glossy, touch screen), so the Benq is a slight improvement. But I still cannot live with it.
2 weeks ago I found an old CCFL Philips 22'' monitor. Wonderful. All pain is gone, and it comes back only when I go back to a LED screen.
I need more monitors because I work at different offices and I also need several laptops. So my one and only "new old" CCFL monitor is not enough. I'm trying to buy another one on ebay... Insane.
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Alexandre This sort of thing is so confusing. At first I thought my strain was LED related as I'd mostly used CCFL for last 5 years, but then I realized I used an LED MBP for a time without issue in the past, and an iPad 2 on iOS9 and a Windows Phone Nokia from 2014 are ok as well still now. I have seen bad CCFL displays and so have others here. So its clearly not just "led is bad" or "CCFL" is good and it makes it very hard to pin down root causes.
Actually I think that the issue could be tackled both ways. Either by understanding what exactly is missing in our eyes/brains/body that causes us to suffer or by finding out what is so harsh in current breed of technology.
Having here someone with understanding of both worlds would be ideal, but I think two types of helping hands should be perfectly fine:
- person with understanding of current graphics / displays technology, knowing recent trends, algorithms used by cards / screens, having acccess to prototype devices that can be configured differently (turning PWM, dithering on/off, changing physical aspects of display, etc.)
- person with good knowledge of neurological / eye issues and potential treatments to solve them (things like vitamines needed, diseases to check, etc.). Basically a medicine doctor, but rather passionate with analyst skills, not someone trying to find always the same solution.
I know we probably don't know any expert of such categories, but maybe someone sympathetic will stumble upon this forum one day 
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andc I know not everyone agrees but I am a firm believer in most cases this is firmly a tech problem, most likely SW which is making the HW do things that hurt, and not an eyesight problem. I believe that because most of us don't have issues with some tech and with paper and daily life. If you have an eye disease or problem it would affect you in more use casest than specific LED displays. I can look at a specific CCFL display on a super old laptop for unhealthy amounts of time like 12-16 hours without eye pain...my back and butt hurts from sitting, but its not straining. But a few minutes on offensive displays sets me off. That's not a medical issue. That's a tech issue in the same way getting sick from a poison doesn't mean you are unhealthy, it means your body can't handle that noxious stimulus.
It "feels" logical that it's movment/flickering since that is tiring to look at in general when its visible, strobes lights etc, that it would be tiring when your eyes/brain can see it but you don't notice it. That also explains why older stuff is often better, its not as capable of as much visual trickery. Nobody is bothered by an ancient LED calculator, but modern computer displays hurt most of us. I have also never seen a case where a fancier or more expensive tech solved the issue. Most of what people can use is older.
For a time I believed PWM was the problem but for myself and many others it's proven not. In fact I have never seen someone state removing PWM/LED/anti-aliasing or any of the others from the equation solved their problem entirely across all devices and OSes. Dithering may or may not be the "real" problem but until we can shut it off and see its all speculation and what does work for us might just be good fortune as the dithering is happening but just not being displayed etc due to HW limits. There just isn't any other obvious culprit at this point. The only people I have seen get better overall are those who say the symptoms just went away, so some people can obvious get used to the noxious thing, but its still clearly happening.
Another way to show it is software is to go the reverse way e.g. if somebody here has a 20xx/201x great monitor/gpu combo - put latest Windows 10 on that machine or update XP/W7 etc with the latest driver and see if there are any ill effects from that.
The fact that W10 on my 100% good 2010 PC causes me discomfort tells me there is most likely something in the software/modern 2015> drivers - dithering permanently enabled perhaps?
Only trouble is as others have mentioned maybe it's baked into the vbios of modern cards, so a temporal dithering solution may help in a pcoip scanerio but not change how the image is displayed on the screen.
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Yeah I wish we had the organization to do some more objective testings. It's a few years of anecdotes and opinions that we are trying to kludge together into some solution.
Both new SW on older HW AND old SW on newer HW lend credence to the "make things pretty with flickering" idea being a problem. The former because the HW can't do those pretty things to the degree the SW asks, and the latter because the SW isn't asking the HW to do them. But without some controlled testing who knows? Also we have seen dithering on the Dasung panels so we know its happening, just not if its the problem since we cannot turn it off.
So far every time I swore I had solved it for myself there was an example proving it wasn't the issue...like with PWM. So until we can definitively swtich dithering on or off I don't see how can know...and I've not heard any other plausible theories put forth so far. It's so incredibly frustrating not having ANY solution that works for even a number of people. It's just unexplainable single cases at this point but symptoms are so similar it HAS to be rooted in a similar cause.
In my experience and for my eyes, yes the facts are simple: CCFL is always good, LED is always bad.
For the past 20 years (working a minimum of 8 hours every day, stylesheets, coding, photo, video):
CCFL: desktop, laptop, Windows XP to W10, Linux Mint or Ubuntu => no problem, no strain no headache. And my old CCFL screens do flicker a lot and it's not a problem (though CCFL flickering is "softer" than LED flickering).
LED: smartphone, external monitor, laptop, TV, same operating systems (Windows, Linux), Low Blue Light, Flicker Free, Asus splendid blue light filter, Android filter, Windows night setting, Iristech software, all kinds of settings, low saturation, low brightness, zero contrast, ...
=> immediate pain, headaches, brain pressure, heart beat too high, etc...
In fact, contrast, brigthness, ambient light don't matter with CCFL. Even with not-so-good settings and a bad environment, CCFL do not hurt. While LED, even in a perfect environment with fine tuned settings always hurt.
So I still don't know what it is but I can draw a practical conclusion from that: LED is bad for me, no matter the software or hardware around it.
There must be something else "in" LED light, something beyond blue light.
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Alexandre Alexandre, VA is a significantly different panel technology. I'm testing out a unit that has ghosting just dragging windows and scrolling through text. My question to you is if you've tried a VA panel and had the same lousy experiences you've had with IPS screens. Agreed LED isn't ideal, but VA seems to allow one to use the screen with less exposure to the backlight.
Edit: just read your profile and see that even VA doesn't work for you.
So why is it so difficult to find new CCFL units? Why can't manufacturers make just one current generation unit with CCFL backlighting for niche users like you? What is it about LED that has manufacturers believing it should completely phase out CCFL? After all, we have TN, VA, IPS, and the consensus is that each panel type has its strengths and weaknesses and warrants production for different users.
Edit 2: the ghosting experienced is only when my Ubuntu Night Light is enabled at a strong warm setting. Not sure why that makes the ghosting noticeable when dragging windows and scrolling, but the problem seems solved when I disable it or when I make it less strong. For what it's worth, I quite like the Ubuntu Night Light feature in manual mode where I can enable it and disable it any time, and slide the Color Temperature from less warm to more warm as I see fit.
For reference, even on the warmest Color Temperature in Ubuntu Night Light, my IPS comparison model exhibits no ghosting during the same activities.
NightWolf149 , I also have a bad experience with GW2255. Within seconds I feel eye pinching sensation and some kind of numbness in the brain. I noticed this an year back as well as again a week back. In between, I tried a couple of Dells.
BL2420PT does not present such problems for me. Although its supposed to be flicker free and true 8-bit, I do not seem to have benefited by it, with respect to avoidance of strain.
I use KDE Plasma on Arch LInux.
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ravipra Why might the GW2255 cause pinching and brain numbness? And why do you think the BL2420PT is better?
I had a look at reviews and don't see anyone else complaining of eye or brain issues with the GW2255. From users, it reviews very well.
One returned the 27" WQHD version of the BenQ IPS, saying:
I realized in the first minutes using this that the text in the screen was blurry, tried every configuration but no success. I had to return it to the store. If you're going to code or must see small text in your screen, I don't recommend this.
I recognize at the GW2255 price point users are bound to be less picky, but if they were getting pinching and brain issues I should be able to find an anecdote or two, so I'm wondering what about that unit triggers those symptoms in you and in the original poster. Most don't seem affected.