Point of difference
|
RODS |
CONES |
| Number |
More numerous, 125 millions in each eye |
Less than rods, 7 millions in each eye |
| Photosynthetic pigment |
Rhodopsin |
Iodopsin |
| Sensitivity |
Sensitive to light |
Less sensitive to light |
| Vision |
Dim light (Night vision) |
Bright light |
| Visual pigment |
Only one, black-white |
3 visual pigment, to differentiate colors |
| location |
periphery of retina |
center of retina |
| Speed of response to light |
Slow response: long integration time |
Fast response: short integration time |
| Shape of outer segment |
Cylindrical |
Conical |
| Size |
Small |
Large |
| Light level |
Scotopic |
Photopic |
| Absolute sensitivity |
High |
Low |
| Visual acuity |
Poor; many rods share common neuron connection to brain |
Good; each cone cell has its own neuron connection to brain |
