Entry

What is the density of rods and cones in the human retina?

Jun 6th, 2001 07:54
Per M Knutsen,

Extrapolation of density distributions estimates that cone density in 
the foveola is about 150-180,000 cones/mm2. Towards the retinal 
periphery, cone density decreased from 6000 cones/mm2 at a distance of 
1.5 mm from the fovea to 2500 cells/mm2 close to the ora serrata. Rod 
density peaks at 150,000 rods/mm2 at a distance of about 3-5 mm from 
the foveola (exact number in foveola lacking). Cone diameter increases 
from the center (3.3 um at a distance of 40 um from the foveola) 
towards the periphery (about 10 um). Rod diameter increases from 3 um 
at the area with the highest rod density to 5.5 um in the periphery. 
References:
Jonas et al. (1992) "Count and density of human retinal 
photoreceptors", Graefes Arch Clin Exp Ophthalmol, 230(6):505-10