This sounds like scintillating scotoma: https://en.wikipedia.org/wiki/Scintillating_scotoma
My aura was similar to their description. I would be reading, and the words before or after the current one would be gone. I figured it was the migraine disrupting the visual processing parts of the brain so much so that the automatic filling in of the blind spot stopped working.
I realize there are people experiencing migraines and other painful experiences, but if you have occasional "I can't see right / my head hurts" experiences, consider seeing if drinking a lot more water helps. ;)