bkdo -- Symptoms were pain in the eyes, mild headache (never migraines), feeling like the screen was hard to look at, hard to concentrate on the text, mild brain fog type symptoms.
I've never had problems with phones.
I am able to use the M1 without significant problems these days. I have some eye strain sometimes but that's in the territory of what I experienced with my old computer. It's not affecting my productivity during the workday I think. I feel the eye strain sometimes if I'm working at night (though might be the Flux color scheme). My schedule is to not work in the evenings/at night so it doesn't bother me too much.