Rods

Category

Vision

Function

Scotopic vision, motion in dim light

Quantity

~240 million (120 M / eye)

Density

Peak ~150,000 / mm² mid-periphery; ~0 in foveal pit

Distribution

Almost entirely extra-foveal retina; both eyes equal

Relative Deployment

Notes

Highest photon sensitivity of any photoreceptor. Outnumber cones ~20:1. Density falls toward the far periphery after a mid-peripheral peak.

Interacting Systems & Components

• Photoreceptor (broader category)
• Rhodopsin (RHO) (photopigment gene)
• Nervous System (sensory signaling)