Rod and Cones

1. Vision
2. Rod and Cones

The rod and cone cells mediate photoreception. The rod cells, named after their forms, are perceptive to the light intensity, while as the cone cells are perceptive to color. The rod cell is a structure with 500-2000 disks. The rod cells are metabolized in 10 days. The rod cells can detect shapes of object and are sensitivbe to lower light intensity than the cone cells. The rod cells reaction is slower than the cone cells. The rod cells can detect light at most 12 Hz whereas cone can detect 55 Hz. The cone cells approximately corresponds to ganglion cells in number and the color perception.

The fovea is the most cone dense region. There is no cone cell that perceives blue. The macula (lutea) is an area around fovea. The cornea is surrounded by sclera and dura mater. The choroid goes beneath retina.