Define the term- Adaptation
The terms scotopic and photopic vision are relative to the lighting conditions of an individual place. Light adaptation is a very quick process and is complete within a few minutes. Dark adaptation usually takes much longer. In the dark, the concentration of rhodopsin increases. Under these conditions, the sensitivity of the eye is more than ten thousand times greater than the light adapted eye. When light is admitted to the dark adapted eye breakdown of rhodopsin occurs. Once the eye reaches a steady state level, it becomes more light adapted and it's sensitivity decreases. Therefore, an increase in rhodopsin and a decrease in the amount of end products in the retina yields a higher light sensitivity.