Which photoreceptors are concentrated in the fovea and support high-acuity color vision?

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

Answer: (B)

Cones drive high-acuity color vision. The fovea is the central retinal region specialized for sharp, detailed vision and is densely packed with cone photoreceptors, with rods essentially absent there. This arrangement provides small, tightly focused receptive fields and a near one-to-one wiring to downstream neurons, which yields excellent spatial resolution. Cones come in different spectral types (roughly short, medium, and long wavelengths), enabling color discrimination in bright light. Rods, while more light-sensitive, have large receptive fields and are located away from the fovea, supporting peripheral, low-light vision rather than high-acuity color vision. Other cells mentioned are not photoreceptors; they process signals from photoreceptors after light is detected.