Just a test, what happens if you set the "refresh rate" to 60Hz in the graphics settings, does it give you strain?
What OS and graphics card are you using?
Assuming the graphics card can output the refresh rate itself it should be able to do it. FreeSync/G-Sync is for adjusting the refresh rate on the fly to avoid tearing without V-Sync (induces input lag).
Oh I see your on OSX with a MacBook.
Just a thought, might not be accurate, but maybe since the screen is running at a higher refresh rate the dithering is "running" at a faster rate?
If that's the case just wait until I get my dithering fixes done. 
KM 240 Hz with any graphics card
Well, you need a graphics card that does 240Hz of course. I think those should be ones that can drive 4k screens at 60 Hz. The screen I have has full HD at 240Hz. That is one quarter the resolution of 4k at four times the refresh rate...
JTL "refresh rate" to 60Hz in the graphics settings, does it give you strain?
Yes, it does. Also the 144Hz that the screen supports. 240Hz is really nice for me.
KM Yes, absolutely. But I still feel a bit discomfort when using Firefox Quantum vs. using Safari. So there is still something going on but the main source of flicker is eliminated.
Hey there, just to give you an update. I have used this screen intensively for 6 days in a row now with 6-7 hours straight pretty much every day. I have to say that I have quite some headache now. Not sure if this is the screen, dry eyes or simply stress because I had to finish my task on time.
Will investigate further and update.
KM Have you ever come across this website in your research before?
MagnuM No, but I definitely get motion sick when playing 3D games where you move quickly and the path is narrow. Or when I watch related videos. The more open the field, the better it gets.
Edit: To clarify, my quoted comment was not related to this. The question I asked was to understand if 144 Hz may help with eye strain you get when you look at static screen content (e.g. Windows 10, Firefox Quantum, some Android versions...).
deepflame I expected as much since it takes a few days for most new stuff to really show you if it's going to be ok long term. I didn't think refresh rate should help based on personal experience and the way LCD's refresh, but it was worth a shot. Whatever the root cause is for you is still happening.
hpst Did you find a setup that is working for you for long periods of work in front of a screen yet?
I have to say that I was diagnosed with nystagmus (uncontrolled eye movement/flickering) and thought that my condition might have to do with that as well. However I can remember that I had streaks of long working hours years ago like most of you had. Or maybe I just get old(er), not sure
deepflame I have some weird eye stuff as well but it's proven not the root cause of my problem. I wouldn't argue it can make things worse...but there is definitely a technology issue at play here for 99% of people in my opinion as proven by the fact everyone has at least one "safe" thing they can look at...and we don't have the same strains in non screen related life.
JTL I've had nystagmus
so you mean it is gone now with your "special treatment"?
JTL Just a thought, might not be accurate, but maybe since the screen is running at a higher refresh rate the dithering is "running" at a faster rate?
If that's the case just wait until I get my dithering fixes done.
It might be the case - in my tests Ipad Pro (120 Hz) didn't show sings of flicker, unlike 60Hz displays. I guess it will be more likely to be related if dithering happens on hardware side, but who knows
@jasonpicard had some very valuable inputs on the "flicker free LED lights" thread ( https://ledstrain.org/d/106-flicker-free-led-lights/109 ) and I thought of rather continuing the discussion about gaming gear/ overdrive functionality here.
@jasonpicard I understand that this tech may be very interesting for gamers but I wonder how and why it should help people like me who mostly read text and watch some Youtube videos?
When you told that the LG24GL600F solved all your eyestrain issues that you had for around 11 years I was wondering if the overdrive function smoothens out every flickering there is coming from the computer by (if I understood correctly) predicting the next pixel/color values and interpolating their values to 144Hz?
Did you also have issues before when looking at a steady Windows desktop where nothing is moving? I have issues now looking at a phone or screen for some seconds and react to it immediately (and there is no active motion like video).
Does BlurBuster have an updated list of monitors with good overdrive features and is the one you have now "the best" on the current market in this regard?
deepflame I totally had issues even when reading text on a screen or a webpage or doing anything. Someone just was showing me a video on his crappy phone and it was hurting my eyes. Did you watch the video on eye tracking? https://www.blurbusters.com/faq/oled-motion-blur/ Look at this page and check out the explanation of eye tracking. Every LED/CCFL follows this rule. That is why a higher refresh rate will help. The way I understand it though is it will take to a 1000hz refresh rate to equal a CRT without using tricks like overdrive and black frame insertion, https://www.blurbusters.com/blur-busters-law-amazing-journey-to-future-1000hz-displays-with-blurfree-sample-and-hold/
Check out the journey to a 1000hz article. LED's are kind of terrible when you look at these rules they follow. Your brain has to compensate for crazy things happening. In regards to your Youtube question my question would be does anyone on here no what Youtube videos are filmed at? Is it 24 frames or something else. This will create a different problem then reading text on a website. Movie Theatres usually run at 48 or 72 refresh rates so movies will work perfect with them because movies are usually filmed at 24fps. They double scan or triple scan the image and I think this makes it flicker free. Last generation CRT's were capable of this running at 100hz or 120hz and doing a double scan trick making them flicker free.