Ive been having a similar problem... I believe it has to do with HDR bloom and FXAA but I disabled FXAA in my options and that didn't seem to help... Ive been desperately waiting for a fix. There are caves and even outside in some cities where literally I cannot see any details.. its just pitch black. I have the brightness all the way up on my monitor and the game.. and the brightness so high on my monitor it makes everything too bright and in skyrim I still cant see inside these shadows.