What light-sensitive cells in the eye detect colors?

The light-sensitive cells in the eye that detect colors are called cones. They are photoreceptor cells located in the retina and work best in bright or daylight conditions.

Most humans have three cone classes: S cones respond most strongly to shorter wavelengths, M cones to medium wavelengths, and L cones to longer wavelengths. The brain compares the strength of these signals to produce the wide range of colors we perceive; no single cone type detects an entire color by itself.

Cones also provide sharp visual detail. They are especially densely packed in the fovea, a small central region of the retina used for precise vision. The human eye has roughly six to seven million cones, compared with many more rod cells.

Rods are the common source of confusion. Rods are much more sensitive in dim light but contribute little to ordinary color vision. That is why colors fade in darkness, while cone-based color vision is strongest in daylight. Variations in cone pigments can also cause forms of color blindness.