In select cases, users report suffering headaches and eyestrain from using LG W-OLED and Samsung QD-OLED desktop monitors (And TV's). A select amount of these users report that they don't experience eyestrain after using smartphones with OLED displays. If you're that person, this thread might be helpful to you.
I fall into that category myself. I've used iPhones, Galaxies and Pixels and even when I used them in the ''worst use case'' scenarios meaning in a pitch black room, under bed sheets, very closely to the eyes, my eyes feel fine after long term use (hours).
I've recently bought a few OLED monitors. These all result in very noticable eyestrain, burning eyes, dry eyes and general discomfort after 15 minutes of use. Here's the OLED monitors that I've bought and tried:
Philips 27E1N8900 J-OLED series monitor (4K60)
Innocn 15A1F AMOLED monitor (1080p60)
LG 27GR95QE W-OLED monitor (1440p240Hz)
The odd thing about this is that LG W-OLED and Samsung QD-OLED monitors are regarded virtually flicker free, whilst the smartphones are known to flicker with high modulation. Yet, some users report that the eyestrain happens with the monitors, not the smartphones. So here we try to reason why.
I've used a smartphone with slow shutter speed to record the frequency graph and behaviour of OLED smartphones and then the monitors. Here the following becomes clear. The smartphones below 60% brightness have thicker black lines going through the screen, these are the off cycles. Them being thick, means the off cycle is longer. So long, that the off cycles look longer than the on cycles in some cases. Illustration here, with in red marked the ''off'' cycle, which in this case seems to help.
The monitors, including all 3 I've listed above, exhibit significantly less black lines that are also much thinner, when measured with a slow shutter speed camera. Here, the duty cycle looks ''on'' for the major part (illustration added as an example), with occasionally a thin/faint line (or 2-3 max) going through the screen
So theory number one is that the long ''duty on cycle'' seems to hurt the eyes. Which also raises a possible theory that a permanent on (meaning fully flicker free, no off dip) could actually hurt the eyes more, since well, you get a permanent on cycle. That theory could mean that the nature of how OLED pixels emit light without any flicker possibly hurt a certain group of people. Which would be weird, and I don't know why that would be. But It's interesting to think about.
The second theory is that a long on cycle, paired with the short off cycle is what causes the eye strain and that a permanent on could still eliminate it, or rather longer and more deeply modulated off cycles could eliminate it as well. Why the eyes would be more bothered by the long on cycles, rather than the long off cycles from using smartphones for a select amount of users, is worth thinking about.
I didn't see this be explained like this before, so hence why I decided to post this here.