Hello!
I’ve made a working prototype of a concept: letting the dark areas of the scene get blurred in a post process to simulate how vision would struggle to make out details at low light levels. Attached is a picture, and the youtube link is it in action:
I am no programmer however, and I’ve just made do with a kernel blur with a rather limited radius. I’m sure this can be implemented much much better, at perhaps negligible render cost as well.
Just putting the concept out there, fishing for better solutions 
Cheers!