And this Reddit contains multiple answers: https://www.reddit.com/r/askscience/comments/2n1yd4/how_is_i...
Yes, they get blind from white light.
Yes
But even if we would blind them (either temporarily or permanently), they would remain still mostly functional or fully functional. Still able to feed, move and escape from predators with their other three or four main senses intact. I'm generalizing, of course, each species is different but this means that the animals can always choose to escape from the light, but they aren't choosing it for some reason. Petrified by fear, curious, hungry, or feeling that remaining in the light is safer than running into the obscurity after being exposed... we don't know
On the other hand both, the animals in the light and those who remain in the dark out of the light circle and will not be blinded can have a glimpse of their surroundings in a totally different "light" and access for a brief moment to a totally new understanding of this world.
Would be interesting to know what pass by that cephalopod brain when seeing the real aspect of its companion species for the first time in their life. Will be this information allow them to associate a particular stimulus with the arrival of a particular predator, and be useful in the future? maybe, maybe not.
But it might be worthwhile to blind/kill a few creatures to better understand them to be able to protect the rest.
Edit: And then there's the anglerfish with its bioluminescent lure on its head: https://video.nationalgeographic.com/video/00000144-0a34-d3c...
The seas are home to such fascinating creatures ...