I found my ocular migraines were triggered by my looking out the window in the morning while I brushed my teeth. On sunny days it was a lot of brightness to take in. Since I stopped doing that I haven’t had a single one.
Yes, the change of light intensity is a common trigger for me. Either looking at a screen and then outside, or vice versa, or even bright led lights. But they've still largely gone away with regular magnesium supplementation and occasional psychedelic use (a few times per year).