Facts:

1. In the dark the human eye cannot perceive color basically because the cells in the eye that see color cannot function within a certain range of brightness.

ITS OK THAT IN NIGHT TIME WE CANNOT SEE COLOR.

2. The character SHOULD be able to see better in the dark the longer it survived due to the human's eye hability to adaptate to low levels of brightness. For example, if you were in a room with all the light on and then you turn them off, you will see very little or even not see at all, but after a couple minutes you will slowly start to see better and finally be able to see quite well in the dark with at least a minimal source of light (considering moonlight).

THERE SHOULD BE A MECHANISM THAT REGULATED NIGHTSIGHT OVER TIME.