Which photoreceptor cells are active in bright light and allow color vision?

• A. Rod cells
• B. Bipolar cells
• C. Cone (cells)
• D. Ganglion cells

Answer: (C)

In bright light, color vision comes from cone cells, the photoreceptors that respond to higher levels of illumination and encode different wavelengths. There are three types of cones, each sensitive to a different range of wavelengths (roughly short, medium, and long), and the brain interprets color by comparing the signals from these cones. Cones provide high-acuity vision because they connect to fewer photoreceptors per ganglion cell, especially in the fovea, where detail is sharp. Rods, by contrast, are specialized for low light and do not convey color information, so they don’t support color vision. Bipolar cells and ganglion cells are not photoreceptors themselves; they relay and process signals from photoreceptors to the brain. So, the cells active in bright light that allow color vision are cone cells.