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AR / VR Science Note 002: Rod and Cone Density

There are approximately 100–120 million rod and 7–8 million cone photoreceptors in each retina (Riggs, 1971). As shown in the distribution graphbelow, most cones are concentrated in the fovea, while rods are absent there but dense elsewhere. Despite the fact that perception in typical daytime light levels is dominated by cone-mediated vision, the total number of rods in the human retina far exceeds the number of cones (Purves et al., 2001).

This graph shows why we see color (photopic vision) most clearly in our direct line of sight. The peak number of cones occurs in the fovea, where it reaches approximately 150,000 cones per square millimeter.



Riggs, L. A., “Vision.“ In J. W. Kling & L. A. Riggs, eds. Woodworth and Schlosberg’s Experimental Psychology. 3rd edition. New York: Holt, Rinehart, and Winston (1971).

Purves, D., G. J. Augustine, D. Fitzpatrick, L. C. Katz, A. S. La Mantia, J. O. McNamara, and S. M. Williams. Neuroscience, 2nd edition. Sunderland (MA): Sinauer Associates (2001).


This AR / VR Science Note is based on content drawn from the book Practical Augmented Reality: A Guide to the Technologies, Applications and Human Factors for AR and VR (Pearson / Addison Wesley Professional, Fall, 2016).

Reproduced by the author with permission from Pearson © 2017.


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