The light effects in the boss trials are ridiculous. I have every setting I can find turned down or off to potato level graphic quality, and this is still a problem. There are Google search results for "FFXIV causes headache" going back to 2013, so this is not a new problem, nor a problem unique to me.

It is, however, a problem unique to your game. This has been expressed frequently in other forums posts over the years, as well as other websites dedicated to the game.

I had a good laugh at this post, where someone blamed it on the player's diet: https://forum.square-enix.com/ffxiv/...-FF14-Sickness

For real, though. You need to fix this. More and more people are coming over to FFXIV from other games, and no one is trying to go blind.