Book Definition:

Sensory objects located in the back of your eye that are sensitive to colors.

In Your Own Words

  • Cells that enable detection of light waves that we sense
  • Cone-shaped things that enable you to see color
  • photoreceptors located in the retina


  • If you were being attacked by a very bright killer rainbow monster, then your cones would be much more active than your rods.
(That's Mr. Wray's depiction of a KILLER RAINBOW!)

Additional Resources

click here for a diagram of the eye/ rods and cones (once there click on the tab that says rods and cones)

external image 180px-BirdCone.png external image rcdist.gif
Above is a diagram of a cone; here you can see how the the cone density is compared to the rod density.


used for night vision
used for day vision
very light sensitive; sensitive to scattered light
not very light sensitive; sensitive only to direct light
loss causes night blindness
loss causes legal blindness
low visual acuity
high visual acuity; better spacial resolution
not present in fovea
concentrated in fovea
slow response, to light, stimuli added over time
fast response to light, can perceive more rapid changes in stimuli
have more pigment than cones, so can detect less light
have less pigment than rods, require more light to detect images
stacks of membrane-enclosed disks are unattached to cell membrane
disks are attached to outer membrane
20 times more rods than cones in the retina
one type of photosensitive pigment
three types of photosensitive pigment in humans
confer achromatic vision
confer color vision