The eyes need time to adapt from the brightness of day to the darkness of night. This is called dark adaptation. It takes about 20 minutes for your eyes to fully adapt to the dark once you enter a dark environment, such as an unlit room or unlit aircraft cockpit.

Rods (which are sensitive to low light levels) become more active than cones (which are sensitive to high light levels). This is called scotopic vision and occurs when you first step into a dark room or aircraft cockpit; you may notice that objects in the room appear hazy or blurry.

Cone activity increases until it matches rod activity, so that you can see objects clearly in both dim and bright lights. This is called photopic vision and happens after about 20 minutes of being in a dark environment.

Last modified: August 18, 2022