Dark Adaptation

Dark adaptation is the process by which the retina adjusts its sensitivity to compensate for low levels of ambient light, part of the eye broader capacity for adaptation to changing light. Rod cells, which are exclusively responsible for night vision because cone cells only function at higher illumination levels, must undergo a period of adjustment lasting up to about two hours when moving from daylight into darkness, during which visual sensitivity increases dramatically as photopigment in the rods regenerates. Vision achieved through this process, known as scotopic or night vision, has lower resolution and no color perception compared with ordinary daytime vision. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/