Both rods and cones
Explanation
The human eye functions as a natural optical instrument. Light enters through the cornea and is focused by the crystalline lens onto the retina, which acts as a light-sensitive screen. The retina converts light energy into electrical signals via specialized photoreceptor cells, which are transmitted to the brain through the optic nerve.
Analysis of Photoreceptor Cells:
The retina contains two primary types of photoreceptor cells, each serving a distinct function in visual perception:
- Rods: These are rod-shaped cells that are highly sensitive to light. They function primarily in low-light conditions (scotopic vision) and are responsible for peripheral vision. Rods do not detect color.
- Cones: These are cone-shaped cells that require higher light intensities to function. They are responsible for daylight vision (photopic vision), high visual acuity, and color perception.
Since the human visual system requires the ability to see in both dim and bright environments as well as perceive color, the retina contains both rods and cones.
Key Takeaway:
The retina contains rods for night vision and cones for color and daylight vision.