Which photoreceptors are primarily responsible for color vision?

• A. Rods
• B. Bipolar cells
• C. Ganglion cells
• D. Cones

Answer: (D)

Cones are the photoreceptors responsible for color vision. They require brighter light and come in three types, each with a different photopigment that is most sensitive to short, medium, or long wavelengths—roughly blue, green, and red. The brain compares signals from these three cone types to resolve a wide range of colors. In dim light, vision shifts to rods, which are highly sensitive but provide no reliable color information, so colors disappear and vision becomes grayscale. Bipolar and ganglion cells are important for passing and processing signals, but they are not photoreceptors themselves. Cones are densely packed in the central retina, supporting sharp, color-rich vision in bright light.