Basically we suffer from 3 sources of eye strain that most people don't have big problems with:
- area flicker (screens using PWM or other flicker, flickering LED bulbs etc.)
- pixel flicker (temporal dithering but also other pixel flicker)
- spectrum (brightness issues)
In more detail:
area flicker:
You say TVs are OK. As most of them do flicker heavily, this is perhaps not the problem. Though I'd suggest anyone to get some flicker detection equipment just to get more information about the devices they can and can't use: https://ledstrain.org/d/312-homemade-oscilloscope-to-detect-pwm-diy-guide
Sometimes the room lighting can flicker, causing symptoms, too. Small status LEDs, dashboards, keyboard lights...
pixel flicker:
This is happening lately with all kinds of operating systems, even on smartphone. We still are unsure about the causes. Allegedly some temporal dithering algorithms can trigger symptoms, but there's most probably even more to it. The only thing that sometimes helps is trying to turn off temporal dithering (you will find many discussions about that in this forum) or changing the OS. Or turning off desktop hardware acceleration, or not using problematic applications (for example changing the web browser). This list is not complete, it should just give an idea of the problem.
spectrum:
You may have this issue if you quickly find the need to turn the brightness of your screen way down, eventually reaching brightness levels that make it difficult to recognize the screen content anymore in a normally lit room. I assume that this may happen less with screen technology that is not using White OLED. E.g. AMOLED (not White OLED!), Quantum Dot, etc. may be less aggressive in this regard. But that is based on some anecdotal evidence. If you have this issue you may have problems with most LED bulbs, too. Spectrums can quickly be revealed with cheap handheld spectrometers.
So basically, gathering more information by trial and error is most important.
- Car screens and digital dashboards around 2016 onward.
- a car that gave me a migraine every time I drove it
I know that, too. Most armatures nowadays flicker heavily. This also means that the bursts of light are much brighter than what we consciously perceive as the average brightness. I get symptoms within seconds even when I'm not the driver and the lights are just in my peripheral site. Most cars probably use White LED, which is the cheapest technology currently. There might be a chance the symptoms appear only in combination (bright White LED + flicker).
Any phones (iphone/android - I've tried lots!) 2016 and beyond, including IPS/TFT/OLED. iPhone 7 onwards all trigger
Escpecially AMOLED phones usually use PWM. Some, very few, only flicker below a certain brightness. I have such an AMOLED phone. If I go below the PWM brightness threshold, I get symptoms quickly. That way I could clearly understand that the PWM flicker was the main problem, and not the underlying AMOLED technology or something else. Noteboockcheck.com regularly tests smartphones for PWM.
screen filters don't seem to help
Same here. If I perceive a display's light (spectrum) as aggressive, no amount of filtering helps.
I've had the 2 [monitors] of the same model where one has worked and one hasn't
Happened to me, too. One is, in retrospect (the better devices you find, the worse the previous ones appear), borderline usable, while the other one is outright unusable and triggers symptoms fast. I found there's slight differences in flicker and also in backlight color. As they use White LED (I can only use them at low brightness) and flicker a little (being advertised as "flicker-free") they weren't an optimal choice to begin with.