What do rods detect in human vision?

Rods are photoreceptor cells located in the retina of the eye, primarily responsible for vision in low-light conditions. They are particularly sensitive to light and allow us to see in dim environments. Unlike cones, which detect colors, rods do not contribute to color vision; they are designed to detect varying levels of light intensity. As a result, rods are fundamental for night vision and primarily perceive shades of black, white, and gray.

This ability to detect shades and variations in light without color makes them essential for seeing in darkness and helps in motion detection in low-light conditions. The specialization of rods in capturing brightness and contrast in black, white, and gray allows for effective night vision and peripheral vision, while cones are responsible for color perception and visual acuity in brighter light conditions.