Lighting Design Glossary

Scotopic Vision

(Term of physiology)

Scotopic vision is the scientific term for human vision "in the dark", below 0.034 lm/m².

In that range, the human eye uses rods to sense light. Since the rods have a single absorption maximum of about 1700 lumens/W at a wavelength of 507 nm, scotopic vision is color blind. The sensitivity range of the rods makes the eye more sensitive to blue light at night, while red light is almost exclusively perceived through photopic vision.

In the range above 3.4 cd/m², the human eye uses photopic vision. In the intermediate range, mesopic vision combines both types.