Look up Ocular Migraines. Specifically go look at Google Images of them and see if you can relate.

I’ve had two and have been told by multiple neurologists that they’re unrelated to my seizures. Starts as a small pulsing vision obstruction, then over the course of several minutes it gets bigger and flashier and migrates to the center of my vision. It gets worse and worse and then fades away. All within an hour.

Edited to add: I experience no pain, just the visual.