Which visual system is most sensitive in low-light conditions?

The scotopic system is indeed the most sensitive in low-light conditions. It primarily relies on rod photoreceptors, which are highly sensitive to light and enable vision in dimly lit environments. Rods do not contribute to color vision but are effective in detecting movement and shapes under low illumination. This makes the scotopic system crucial for nighttime vision or in dark rooms where light is minimal.

In contrast, the photopic system, which comprises cone photoreceptors, operates best in bright lighting conditions and is responsible for color vision and high-acuity tasks. The mesopic system is a combination of both rod and cone responses and functions in intermediate light levels, like dawn or dusk, but it does not have the sensitivity to darkness that the scotopic system has. The chromatic system deals with color perception, which is not significant in low-light scenarios since color discrimination relies on cones.

This focus on rod function highlights why the scotopic system is paramount in low-light conditions, distinguishing it from the other visual systems that are either geared toward brighter light levels or color perception.