Mesopic vision is the transitional mode between photopic (daylight) and scotopic (night) vision. It occurs in dim light or other situations with low illumination, such as twilight or in a dimly lit room.
Features of mesopic vision:
- Combined use of cones and rods : Both types of light receptors in the retina work together, but with shifting dominance.
- Limited color perception : Colors are perceived as less intense because the cones are less active.
- Increased sensitivity to blue-green light (~507 nm) : This is because the rods (which become more active in dim light) are more sensitive to this wavelength.
- Decrease in sharpness : Because rods perceive details less well than cones, the resolution decreases slightly.
- Shifting vision : You may sometimes notice that objects are more visible when you look just off to the side, because rods are located closer to the edge of the retina.
Examples of mesopic vision in practice:
- Driving at dusk : It takes time for your eyes to adjust to changing light conditions.
- Street Lighting and Night Lighting : Lighting design often takes mesopic viewing conditions into account to improve visibility.
- Astronomy and night vision : In low light, you can see objects better by looking just to the side ( averted vision ), because this makes more use of the rods.