I have heard some blind people can detect flashes.
Blind, like deaf, runs the spectrum from legally blind but still able to see limited distance with glasses, to completely blind, zero vision at all.
And excellent books I read was about a blind man who was in the Towers the day they got hit and hose he got out with the help of a friend and his guide dog.
But interspersed with that story were accounts from his growing up years. It is amazing to see how able some fully blind people are at navigating their environment.
The books was called Thunder Dog by Michael Hingson.
Thunder Dog: The True Story of a Blind Man, His Guide Dog, and the Triumph of Trust
https://www.amazon.com/Thunder-Dog-Story-Blind-Triumph/dp/1400204720
It’s a great book and something a child could read it’s so clean and not woke or perverted.
Thanks for that. You are such a FR treasure :)