Britannica
Sources used in this answer
Where are rods and cones located in the human eye?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
Photoreception
The mammalian eye has a cornea and a lens and functions as a dioptric system, in which light rays are refracted to focus on the retina.
Rods and cones are specialized light-sensitive photoreceptor cells located within the retina, the nervous tissue layer covering the back of the human eyeball. These cells are situated in a specific layer of the retina, positioned behind other retinal cell layers that light must pass through to reach them.12
Their distribution across the retina varies:
- Cones: These are most densely concentrated in the fovea centralis, a small depression at the center of the macula lutea. The central fovea contains exclusively cones and no rods. As you move away from the fovea toward the outer edges of the retina, the density of cones decreases.312
- Rods: These are distributed across the entire retina but are absent in the central fovea. They are found in higher densities in the regions surrounding the fovea, such as the parafovea.312
In total, the human retina contains approximately 7 million cones and between 75 million and 150 million rods.2