Hi,
Same thing here, eye strain.
I play on an OLED TV (LG C4), with bias lighting in the room.
Playing as Paladin and some action like "Confiteor" is too flashy. In addition of certains boss move that are very flashy and take 3/4 of the screen in very short time.
I was wondering what causing my eye strain and migraine. I started to have when I replayed FFXIV for Dawntrail and when I doing some 7.0 to 7.31 contents. (Sand Oria raid for example)

I dunno if I have to stop my subscription until they fixe this things, my head hurts when I play this game, and this is annoying because I play on console (xbox) and I can't change anything in video settings...

Hope they'll do something