Friend of the Night

 is a perk in Fallout: New Vegas.

Effects
You are a true friend of the night. Your eyes adapt quickly to low-light conditions indoors and when darkness falls across the post-nuclear wasteland.

This perk causes a noticeable increase in brightness at nighttime and shortly after entering any area with low-light conditions. The effect is not a gradual one, and its presence can be recognized by a light blue tint on the game world.