“Visible darkness” is a part of my "Blue" trilogy. When I discovered 4 crescents at the base of my corneas, I thought I was going to lose sight. The anxiety reminded me of Derek Jarman’s “Blue is darkness made visible.” , blue was the only thing he could see before he went blind.
Meanwhile I was hiding in my own corner, chasing the color blue, turned out to be adjusting the distance between the world and me. Blue itself is just like distance, not reachable.