Non-PWM-related IPS/LED eye strain

[sihida]

Some months ago, I purchased a Sony VAIO S15 notebook. This computer features a 15" 1080p LED IPS screen. Yes, the screen looks gorgeous, but after I had used it for a while, I experienced some mild eye strain. The screen's default PPI is quite high (141), so I set the scaling in Windows to 125%, which resulted in a more convenient 113 PPI. However, I'm still experiencing some mild eye strain after using it for some time. Recently, I bought an external 23" 1080p LED IPS monitor: the LG IPS235P. Unfortunately, I'm experiencing the same issues using this new monitor. The eye strain is mild, I don't get headaches or something like that. Nevertheless, it bothers me, in particular as I don't understand what's the cause.

It doesn't seem to be related to PWM: I did the camera test from http://www.tftcentral.co.uk/articles/pulse_width_modulation.htm and it turned out that the Sony's screen is not using PWM to reduce its brightness (did the test at 40% brightness). (The LG does use PWM to reduce its brightness.) It seems not to be related to LED either: I have used the 10" LED (TN) screen from my Samsung NC10 netbook quite extensively, without experiencing any issues. My tablet's 10" screen is also LED and I don't experience any eye strain using it. By the way, this screen is IPS, so it seems not to be related to IPS either.

Does anyone have a clue what could cause this mild eye strain? I'm stuck. As a final note, my previous display was a Samsung T220 CCFL TN monitor (and guess what, no issues).

 

[Mark Rejhon]

Some months ago, I purchased a Sony VAIO S15 notebook. This computer features a 15" 1080p LED IPS screen. Yes, the screen looks gorgeous, but after I had used it for a while, I experienced some mild eye strain.

PWM is sometimes a red herring for other known non-PWM possibilities:

(1) Brightness eyestrain. Try lowering the brightness massively.
The laptop should not be the brightest thing in your view.

(2) Excess blue light. Some LED's have more blue light than others. It has been known that the extra blue light of LED screens can be a problem, disrupting the cicadian rhythm. Some solutions include a slightly yellowish tinted film, to block some excess blue light. Test this temporarily for a day or two. (A simple display recalibration can help significantly, though will not always solve the problem.)

(3) Excess contrast. Some people can't take the excess contrast of an extremely colorful display. Try dulling the screen and seeing what happens (lower contrast).

(4) Motion blur eyestrain. Some people have actually reported this, but this would only be if you're doing lots of things in motion (e.g. games, etc) and you're getting eyestrain from all the IPS motion blur. If you think this is the case, try testing an external fast display temporarily, such as a CRT, plasma, TN, or strobe-backlight display (e.g. Sony Motionflow Impulse, or LightBoost, or Samsung 3D Mode).

(5) Glare. Some Sony laptops have been known to be glossy. If so, try getting some antiglare film.

 

[Nenu]

You may have a sleep related issue where your eyes move a lot at night, causing them to be tired/achy in the day.
If you grind your teeth at night (bruxism), its a similar or the same thing.
Stress makes it worse.

 

[charles_k]

Does anyone have a clue what could cause this mild eye strain? I'm stuck. As a final note, my previous display was a Samsung T220 CCFL TN monitor (and guess what, no issues).

Hi, your case is similar to mine, I have absolutely no problem with CCFLs TN or IPS monitors, but LED ones (TN,IPS,VA ... I tried a lot of monitors) causes me significant eye strain that can lead to a headache in a few hours (PWM makes it quicker and worse).

I should note that my galaxy tab 7.7 (AMOLED) doesn't cause me any eye strain after hours of reading whereas others LCD (LED) tablets do. So i'm eagerly waiting for OLED monitors, in the meantime I am still using my old CCFL IIyama

edit : differences in PPI has no effect for me

PWM is sometimes a red herring for other known non-PWM possibilities:

(1) Brightness eyestrain. Try lowering the brightness massively.
The laptop should not be the brightest thing in your view.

(2) Excess blue light. Some LED's have more blue light than others. It has been known that the extra blue light of LED screens can be a problem, disrupting the cicadian rhythm. Some solutions include a slightly yellowish tinted film, to block some excess blue light. Test this temporarily for a day or two. (A simple display recalibration can help significantly, though will not always solve the problem.)

(3) Excess contrast. Some people can't take the excess contrast of an extremely colorful display. Try dulling the screen and seeing what happens (lower contrast).

(4) Motion blur eyestrain. Some people have actually reported this, but this would only be if you're doing lots of things in motion (e.g. games, etc) and you're getting eyestrain from all the IPS motion blur. If you think this is the case, try testing an external fast display temporarily, such as a CRT, plasma, TN, or strobe-backlight display (e.g. Sony Motionflow Impulse, or LightBoost, or Samsung 3D Mode).

(5) Glare. Some Sony laptops have been known to be glossy. If so, try getting some antiglare film.

In my case :
1) no significant effect
2) I tested gunnar glasses that filters blue light : no effect . Maybe oled has a better spectrum ?
3) Doesn't bother me on my amoled gtab
4) no effect
5) no effect

All this is really weird anyway, my brothers and sisters use LED monitors everyday (some that I tested) with no problem at all, and my eyes are, according to our ophthalmologist, better than theirs.

 

[Mark Rejhon]

6) Viewing distance. Viewing a screen even just a few inches closer than normal (because of high DPI) can dramatically increase eyestrain especially if you are farsighted. Try increasing DPI massively (150%, 175%, 200%) on a temporary basis and force yourself to view from a bit further away.

 

[sihida]

Thanks for all replies.

PWM is sometimes a red herring for other known non-PWM possibilities:

(1) Brightness eyestrain. Try lowering the brightness massively.
The laptop should not be the brightest thing in your view.

I always lower the brightness of my devices to about 140 cd/m2, so I did with the notebook and the LG screen. My room is well lit, so I don't think this is the issue. The brightness of my other/previous devices (which don't cause me eye strain) is/was set to about the same level.

(2) Excess blue light. Some LED's have more blue light than others. It has been known that the extra blue light of LED screens can be a problem, disrupting the cicadian rhythm. Some solutions include a slightly yellowish tinted film, to block some excess blue light. Test this temporarily for a day or two. (A simple display recalibration can help significantly, though will not always solve the problem.)

Thanks, haven't tried this yet. Do I need to calibrate the display to a different color temperature (other than 6500K)? Where can I get this slightly yellowish tinted film? Is it possible to measure the amount of (extra) blue light with a simple colorimeter (Datacolor Spyder)?

(3) Excess contrast. Some people can't take the excess contrast of an extremely colorful display. Try dulling the screen and seeing what happens (lower contrast).

The contrast is of about the same level as my other/previous devices. My smartphone's screen is AMOLED (high contrast) and I love using it.

(4) Motion blur eyestrain. Some people have actually reported this, but this would only be if you're doing lots of things in motion (e.g. games, etc) and you're getting eyestrain from all the IPS motion blur. If you think this is the case, try testing an external fast display temporarily, such as a CRT, plasma, TN, or strobe-backlight display (e.g. Sony Motionflow Impulse, or LightBoost, or Samsung 3D Mode).

Haven't gamed yet on both monitors, so I don't think this is the case.

(5) Glare. Some Sony laptops have been known to be glossy. If so, try getting some antiglare film.

My Sony's screen is semi-glossy with almost no reflections at all. The LG's screen is matte (mild AG coating) and, as I said before, I'm having issues with this screen as well.

6) Viewing distance. Viewing a screen even just a few inches closer than normal (because of high DPI) can dramatically increase eyestrain especially if you are farsighted. Try increasing DPI massively (150%, 175%, 200%) on a temporary basis and force yourself to view from a bit further away.

I'm not farsighted, but nearsighted... Yes, I view the notebook's screen closer than normal, but I view my LG display at normal distance.

You may have a sleep related issue where your eyes move a lot at night, causing them to be tired/achy in the day.
If you grind your teeth at night (bruxism), its a similar or the same thing.
Stress makes it worse.

I don't think this is the case, as I don't have tired eyes when I don't use a screen at all or when I use a different screen.

Hi, your case is similar to mine, I have absolutely no problem with CCFLs TN or IPS monitors, but LED ones (TN,IPS,VA ... I tried a lot of monitors) causes me significant eye strain that can lead to a headache in a few hours (PWM makes it quicker and worse).

Well, as I said, some LED screens don't cause me eye strain at all and I, fortunately, don't get headaches. I just experience more eye strain than normal/usual. So I don't know if your issue is the same as mine... Maybe just related. My LG display uses PWM to reduce its brightness, but I don't feel that I experience more issues and/or faster than my non-PWM notebook screen.


Noteworthy: When I'm paying a lot of attention to the screen/the eye strain (my default mode at the moment...), the eye strain seems to be worse than when I'm really absorbed in the computer activity I'm doing (like watching an exciting movie/series). So I'm thinking that I may hold my eye muscles (too) tight, consciously or unconsciously...

 

[Nenu]

Do I need to calibrate the display to a different color temperature (other than 6500K)? Where can I get this slightly yellowish tinted film? Is it possible to measure the amount of (extra) blue light with a simple colorimeter (Datacolor Spyder)?

Before you try using a yellow film, calibrate the display to 5200K or 4200K if possible and see if that is better for you.
This is the same effect as a yellow filter. The lower the colour temp, the less blue is present and the more yellow it will look.

 

[sihida]

Before you try using a yellow film, calibrate the display to 5200K or 4200K if possible and see if that is better for you.
This is the same effect as a yellow filter. The lower the colour temp, the less blue is present and the more yellow it will look.

Thanks, I'll try. However, http://www.eizo.com/global/library/basics/eyestrain/#tab03 states that CCFL and LED backlights have about the same amount of blue light. As I don't experience eye strain issues using CCFL backlights, I wonder why blue light from LED backlights might cause my eye strain issues...

 

[Nenu]

Possibly because PWM dimming can be used more aggressvely with LED lights.
CFL arent so easy to vary the brightness of, they start to flicker badly of their own accord at lower light (power) levels or even turn off, but even at full power they are flickering at a high frequency through the way they work.
This doesnt happen with LEDs, they will flicker at the PWM frequency only and do not turn off until you remove the power, so you can have mad PWM setups. If using DC on an LED there is no flicker at all.

It depends how they implemented the dimming.
Like it says in that report, DC or PWM dimming of the backlight can be used.
My LED display has different levels you can set the backlight at, (I assume this uses DC for my display as I cant see any flicker, even at low levels).
There is the LCD dimming (brightness/contrast).
There is the auto dimming for high contrast modes that reduces the power of the backlight for darker scenes, this could be PWM or DC.

Its not all down to CFL vs LED, it depends how they have implemented the dimming.

 

[Mark Rejhon]

Before you try using a yellow film, calibrate the display to 5200K or 4200K if possible and see if that is better for you.
This is the same effect as a yellow filter. The lower the colour temp, the less blue is present and the more yellow it will look.

Unfortunately, blue light still leaks through no matter what. Display a black screen as an example; the black screen is usually not yellowish even when you adjust to 5200K, unless you raise the black level of your monitor (brighten the blacks) to allow adjustability of the color tint of your blacks.

 

[sadbuttrue]

LED backlights are actually blue with a yellow phosphor coating. Depending on the manufacturing process, you could end up with one that is far bluer than normal. No amount of colour adjustments will remove the excess blue.

The Eizo claim that CCFL and LED have the same amount of blue light is based on average output. Look at the wavelength graph and you'll see a huge spike pretty close to the UV range. This imo is the reason for LED blue light fatigue.

 

[Mark Rejhon]

LED backlights are actually blue with a yellow phosphor coating. Depending on the manufacturing process, you could end up with one that is far bluer than normal. No amount of colour adjustments will remove the excess blue.
The Eizo claim that CCFL and LED have the same amount of blue light is based on average output. Look at the wavelength graph and you'll see a huge spike pretty close to the UV range. This imo is the reason for LED blue light fatigue.

This is true. Some LED's are far worse than others. If you have a spectrophotometer capable of creating a wavelength graph, you'll be able to analyze different monitors and find the monitor with the lowest blue spike. Then to work that down better, you can also buy a filter that suppresses even more of this. This will help solve blue-light fatigue (which can still occur even with lowered color temperatures, due to LCD panels not being perfectly black in blacks).
Or just wait for quantom-dot backlight technologies (e.g. QDEF) which have a much flatter emissions curve. Or wait for OLED (but good OLED will take quite a bit of time to arrive). In fact, I've heard of people get OLED eyestrain that they don't get with LCD's.

It's hard designing a display that has zero eyestrain for everybody, it seems...
When will fully spectrum-graph-adjustable continuous-spectrum infinite-framerate (or greater than 1000fps@1000Hz) arrive in our lifetimes? No RGB discreteness, just continuous spectrum (infinite primary color channels).
Design your own custom spectrum perfectly suited for your eyes. And none of the problems associated with finite refresh rates (flicker, persistence, motion blur, stroboscopic effects, wagonwheel effects, rainbow effects, etc). This Holy Grail display might not arrive till the 23nd century, on U.S.S. Enterprise...

 

[sihida]

Possibly because PWM dimming can be used more aggressvely with LED lights.
CFL arent so easy to vary the brightness of, they start to flicker badly of their own accord at lower light (power) levels or even turn off, but even at full power they are flickering at a high frequency through the way they work.
This doesnt happen with LEDs, they will flicker at the PWM frequency only and do not turn off until you remove the power, so you can have mad PWM setups. If using DC on an LED there is no flicker at all.

It depends how they implemented the dimming.
Like it says in that report, DC or PWM dimming of the backlight can be used.
My LED display has different levels you can set the backlight at, (I assume this uses DC for my display as I cant see any flicker, even at low levels).
There is the LCD dimming (brightness/contrast).
There is the auto dimming for high contrast modes that reduces the power of the backlight for darker scenes, this could be PWM or DC.

Its not all down to CFL vs LED, it depends how they have implemented the dimming.

Thanks for your reply, but my Sony notebook LED screen does not use PWM to dim the screen, however, I still get eye strain issues, so it's not PWM related, I guess. Or it's related to auto dimming, but I think this is rather far-fetched.

I hope my colorimeter can create such a wavelength graph.

 

[Mark Rejhon]

I hope my colorimeter can create such a wavelength graph.

Just so you know 3-channel colorimeters (RGB) can't do it accurately, you need a good spectrophotometer/spectroradiometer that can measure wavelengths in a fine-grained manner. An example is the i1 pro series.

If you can do this for all your displays, please post the graphs if you see an obvious outlier (e.g. massive peak on the eyestrain-inducing display). This is valuable DIY scientific research material that other people with eyestrain, are interested in.

 

[sihida]

It's the Datacolor Spyder 3 Pro. I haven't used it before (it's my brother's), don't know if it is sophisticated enough.

 

[chahahc]

edit : differences in PPI has no effect for me

interesting...For me ppi seems to be a major factor in eye strain. As an example, I tried out a samsung s27c750p for a little bit (best buy's 15 day return policy, thought i'd try it and if i liked it id keep it). Even with its high contrast and non-pwm backlighting, it still gave me more eyestrain/brain fogginess than my shimian q270 lite. Even my cheapo samsung sa300 tn panel monitor was easier on my eyes. Most high ppi smartphones don't seem to bother my eyes. At least not nearly as much as a low ppi monitor. That's why i'm waiting for sharp to get their igzo panels onto the market. 3200x1800 @ 14" = mmmm....I think.

I think there are different types of eye strain. strain from low contrast feels kinda foggyish, low ppi screens feel headache/brain foggyish, and overly bright screens and pwm sting the eyes in my experience.(for what it's worth)

 

[tfouto]

Just so you know 3-channel colorimeters (RGB) can't do it accurately, you need a good spectrophotometer/spectroradiometer that can measure wavelengths in a fine-grained manner. An example is the i1 pro series.

If you can do this for all your displays, please post the graphs if you see an obvious outlier (e.g. massive peak on the eyestrain-inducing display). This is valuable DIY scientific research material that other people with eyestrain, are interested in.

Does the i1 Display Pro make it possible to make a spectrum wave?

 

[Cloudj]

Any update on this issue? Seems i have a similar problem.

 

[Meob]

bump,

I'm having the same problem now too. I never even knew this was a problem. I've used dozens of monitors at different places over the years and never had a problem with any of them. My home monitor is an older ccfl lcd that I can use for hours without any strain.

I got one of those new 21:9 monitors for Christmas (which I absolutely love) but looking at the thing for just a few minutes burns my eyes like no other and leaves me with a headache for the rest of the day. No idea why, and it's apparently a "flicker-free" model. I didn't even realize that was a thing when I bought it, found it out after the fact. Tried adjusting brightness and sharpness but it still gives me a headache. Never thought about the colors until I came across this thread. The monitor is pretty blue even when set to warm. Much bluer than my older monitor.

Going to try messing around with the colors a bit but I'm probably going to have to return it and return to my small 16:10 ccfl monitor.

 

[igluk]

Looking at LED backlit panels is a bit like looking into an energy saving bulb, that is kind of the fundamental problem here especially with white LEDs

 

[SD45]

Thanks, I'll try. However, http://www.eizo.com/global/library/basics/eyestrain/#tab03 states that CCFL and LED backlights have about the same amount of blue light. As I don't experience eye strain issues using CCFL backlights, I wonder why blue light from LED backlights might cause my eye strain issues...

It's entertaining to watch the manufacturers scramble to deal with this issue. Some of what is being put out amounts to sheer denial, like Eizo's claim that CCFL and LED backlights emit about the same amount of blue light. Other sources disagree: https://pcmonitors.info/articles/the-evolution-of-led-backlights/

Eizo has two recommendations for us. Change the color temperature, and reduce the brightness--big time. Hey--What happened to color accuracy?