Flicker and eye care safety for strobed backlights section

[mdzapeer]

Dear Chief,

A suggestion for adding health and safety tips and their effects, concerning flicker black lights and general display use. I am not in the medical industry but maybe someone with more knowledge can collect the information and put it up in sticky or maybe as a article on the main site.

[Chief Blur Buster]

Dear Chief,
A suggestion for adding health and safety tips and their effects, concerning flicker black lights and general display use. I am not in the medical industry but maybe someone with more knowledge can collect the information and put it up in sticky or maybe as a article on the main site.

You are very right, we need to produce a good, long article about the user experience of strobe backlights. It dramatically goes in both directions for hundreds people versus hundreds people. There is a section in the LightBoost FAQ for both:

Q: Why does LightBoost have MORE eyestrain?
Q: Why does LightBoost have LESS eyestrain?

Q: Why does LightBoost have MORE eyestrain?

This can be because of flicker or brightness.

1. Flicker:Some people are sensitive to flicker: You may be getting flicker eyestrain.
   LightBoost is a strobe backlight. It flickers like a 120Hz CRT.
2. Brightness: If your eyestrain is due to excessive brightness, adjust the LightBoost setting. See Picture for more information.

Common sense rules here. See nVidia 3D Vision Safety Information, which is applicable to LightBoost. LightBoost (for 2D use) is a 120Hz flicker, which is less visible than the 60Hz flicker of 3D shutter glasses.

Q: Why does LightBoost have LESS eyestrain?

This can be because of lack of motion blur, lack of LCD artifacts, and/or dimmer image.

• Lack of motion blur: LightBoost eliminates motion blur. Some people get eyestrain from motion blur.
• Lack of motion artifacts: Nearly all common LCD motion artifacts are gone. There is no multiple-edged motion artifacts caused by generic PWM dimming.
• Brightness: LightBoost can be adjusted to a very dim setting, which can help people who get eyestrain from an excessively bright monitor. See Adusting Picture for more information.

NOTE: LightBoost is not for people who are very flicker-sensitive. See nVidia 3D Vision Safety Information. If you hated CRT, even at 120Hz, then turn off LightBoost.

Eventually, we need to write an article on the phenomenon of eyestrain reductions/eyestrain increases because the reports hugely go in both directions including the upside (e.g. rave reviews and testimonials).
Fortunately, strobe backlights are easy to turn ON/OFF nowadays, often via a button on new 120Hz monitors itself.

[flood]

My own experiences:

from my 2hrs of using an asus vg248qe, the WLED backlight seems to be giving my a bit of eyestrain.

I haven't tested lightboost yet, but I will once my 750ti comes back from RMA

PWM isn't an issue, my laptop has a pwm backlight (~300hz or something pretty low) and I've never encountered eyestrain with that.

I've never encountered eyestrain with a CRT, though at 60hz refresh rate, the flickering can be annoying.

or maybe I just need to sit further away...

[mdzapeer]

Yes it seems sitting further away dramatically reduces any flickering or strain you might have.

After using the XL2720Z coming from a 23 inch screen, the below points sometimes gave me eye strain.

1.Larger screen size and sitting at the same distance as my old monitor.
2.Much brighter backlight, even at zero brightness combined with the above.
3.Console gaming, with 60hz flicker was usually fine but, playing a game (Star Ocean last hope) with mixed 30 fps and 60 fps along with its graphical style is giving me some serious strain. Guess I will disable blur reduction for that one.

To combat eye strain for myself:

1.Sit an appropriate distance from the monitor according to the size.

2.In strobe mode, setting the brightness by turning off the strobing to a level which feels comfortable then turning on the strobing. It seems even though the screen seems to gets dimmer by strobing your eyes are still getting flashed by the normal brightness, well that's my theory and has helped reduce my eye strain.

Now the thing is i am not very flicker sensitive on a CRT, but it does bother me a little on back-light strobing at 60hz, its gets better with higher refreshes.

I would like to say that CRT flicker is not the same as LCD back-light strobe flicker. The phosphor decaying slowly on screen helps with that.

BTW another positive or negative side effect noticed due to blur reduction is that since everything is so clear during fast motion, especially at high frame rates 120+ it really makes you feel your in the scene and spinning around quickly in a FPS can actually end up making you dizzy!

[Chief Blur Buster]

I haven't tested lightboost yet, but I will once my 750ti comes back from RMA

If you're using the VG248QE, then be noted that its biggest issue is the crimson/purple hue in LightBoost mode, as well as the resulting low contrast. Newer strobe backlights don't have this discoloration issue, or as much los in color quality.

[flood]

for my vg248qe, using the icc profile+settings on tftcentral's page helped a lot, mostly from lowering the blue value in color temp.

I haven't tested lightboost yet, but I will once my 750ti comes back from RMA

If you're using the VG248QE, then be noted that its biggest issue is the crimson/purple hue in LightBoost mode, as well as the resulting low contrast. Newer strobe backlights don't have this discoloration issue, or as much los in color quality.

Is it this issue that is improved with ULMB?

[Chief Blur Buster]

Is it this issue that is improved with ULMB?

Yes, and with Turbo240 too, and BENQ Blur Reduction too.

LightBoost = 1st generation
Samsung SA 3D-mode strobe = 1st generation
ULMB = 2nd generation
Turbo240 = 2nd generation
BENQ Blur Reduction = 2nd generation

What I consider as 1st generation strobe backlights -- were all primarily originally designed for 3D glasses use (LightBoost FAQ), and color quality wasn't seriously considered. What I consider 2nd generation strobe backlights are now primarly targeted for 2D mode, with far better color quality and fuller picture adjustments.

[mdzapeer]

Low blue light mode is amazing!, I missed it because of using the programmable key gamer modes 1,2 and 3.

Low blue light mode is available on the XL2720Z series monitors in the standard picture mode. After copying the calibrating settings from the Benq Low blue light review from TFT central. My eyes feel much better after extended use even during low refresh 60hz strobe mode, in fact I hardly notice any flicker just like my old CRT.

But the problem is I need to keep using standard picture mode,and the gamer shortcut keys are kinda useless.

BTW chief i found an post by you which is relevant to this thread, quoting here

Consider the color spectrum: Blue light issue
Another suggestion is the color spectrum. Excess blue light. The Eizo FG2421 might need to be recalibrated to a warmer color. Try Color Temperature 5000 or 6500, so the screen looks more orange, and see how it helps your eyestrain.

Sometimes PWM is a red herring: It is not always the cause of eyestrain/headache.
Also try reducing to a brightness 20% or less, especially since your headache may not be caused by PWM, and you might even get less eyestrain going below 20% (the advice not to go below 20% is sometimes a red herring because only about half of alleged-PWM eyestrain is really truly PWM eyestrain). The BENQ has a low-blue-light mode, while the EIZO requires you to dial-down the color temperature to get the rough equivalent. Also, even at 0% brightness, the EIZO is already extremely bright, so using brightness 50% may still be much too bright.

There are many causes of eyestrain/headaches/vision issues
What you are describing is a very serious issue, and you should discontinue using the problem monitor right away. There are many things that can cause vision/headache/eyestrain problems:
-- PWM
-- Motion blur (headaches from motion blur actually exist!)
-- Brightness
-- Blue light
-- Contrast (too dazzling)
-- Ghosting/Motion Artifacts
-- Excess vision coverage (e.g. covers too much vision)
-- Focussing/distance (e.g. too close)
-- Ambient lighting difference with monitor (e.g. monitor too bright relative to surroundings)

It is very hard to troubleshoot a specific human's sensitivity to a display for eyestrain/vision/headache/health issues. 8% of people are color-blind, while a percentage has "motion-blindness" (google that), yet others are more sensitive to flicker, some are photosensitive (headache from brightness), while a few others are more sensitive to a specific issue. I've heard of strain from EVERY SINGLE FACTOR above. This is why the LightBoost FAQ has "Why Does LightBoost Have LESS Eyestrain?" as well as "Why Does LightBoost Have MORE Eyestrain?", as hundreds of reports go in both directions.

Lots of people get headaches from PWM/flicker but not from anything else. But that doesn't always happen. Some people never get headaches from flicker but gets instant headaches from motion blur.

We've noticed newer TN 120Hz+ monitors unexpectedly seems to have less eyestrain/headache reports
The BENQ gaming monitors albiet TN (and often poor color quality) among the most eye-friendly monitors at the moment because you've got a huge number of modes that you can tweak to escape from eyestrain (PWM-free mode, blur-free strobe mode, low-blue-light mode, high refresh rate, etc). Very few reports of eyestrain from recent BENQ gaming monitors since it's fairly easy to adjust the monitor to avoid a specific cause of your eyestrain.

Discontinue use of monitor immediately if a model gives you unexpected eyestrain/headaches
Do not continue using a monitor that exacerbates eyestrain (with no settings/options/adjustments left to eliminate it). Discontinue it immediately and return it. Eizo FG2421 actually reduces eyestrain for a lot of people, but it has attributes (e.g. high contrast and brightness) that actually exacerbates eyestrain.