Nothing. I do as much as possible in the dark. I know exactly where to stand to pee, and I go by sound. I can hit bottles with my .22 in near pitch blackness, as long as there's a moon for me to figure out if the sight is lined up. The glistening sight trick from Land of the Dead works too. I went caving before, and when we got to the end of the cave, the guides asked if any of us thought we could find our way out WITHOUT USING THE HEADLAMP. Took me twenty minutes. I think touch is the most under-appreciated sense.
I would move somewhere without sunlight, if they weren't all so damn cold.