I picked up a 15 (non-pro) and set it up last night, used it off and on for about an hour. Aside from the actual setup, I did some web browsing, Reddit browsing, and playing with some settings, testing the camera, etc.
I have to say that I didn't notice any real problems. I was having dry eyes over the last few days, and so I think the dry eye situation I was feeling just a bit when using the phone was unrelated. No real issues at all, and I did not wake up with a headache.
This very early, initial test seems positive.
It's so hard for me to tell because I am someone who has frequent (almost daily) headaches anyway- even when I purposely don't use my phone (my current phone is a 13 Mini), so it's been hard to differentiate between just regular headaches I might get anyway, and anything additional caused by the phone.
But last night was a night where I was not having any headaches, and nothing came on when using the phone- so I am hopeful!
There has been a ton of discussion here about PWM frequency, modulation percentage, etc. But I did the unscientific test last night, taking a slow-mo video of this phone in a dark room- and wow it's shocking how the thing strobes like crazy... same way that my 13 Mini looks in slow-mo. (and that was with brightness at 100% and RWP set to about 80%). The flicker did not look any different at other brightness levels.
The one thing I see different on this in slow mo is a thick black band that slowly moves up the screen- whereas when I record slow-mo video of my 13 Mini, I see the flicker- but don't see any band or lines.
Not sure what that means?
When I take the same slow-mo video of my wife's 14 Plus, interestingly I see no bands/bars, and see significantly less flicker- it's a subtle flicker vs the entire thing strobing like crazy as I see on my two phones.
I know everyone is different in their sensitivities, but it makes me wonder if my wife's 14 Plus is an overall healthier phone to be looking at for long periods of time, given that lack of visible heavy flicker in slow-mo as I see on these other two phones.
Anyway, I just wanted to share!
I'll continue testing over the next week or so (including taking it and my current phone out on a hike this weekend to test and compare the cameras) before deciding if I want to return it or not.