Light-sensitive tissue lining the inner surface of the eye
- The optics of the eye create an image of the visual world on the retina, which serves much the same function as the film in a camera.
- Light striking the retina initiates a cascade of chemical and electrical events that ultimately trigger nerve impulses.
- These are sent to various visual centers of the brain through the fibers of the optic nerve.
- It is a layered structure with several layers of neurons interconnected by synapses.
- The only neurons that are directly sensitive to light are the photoreceptor cells.
- The vertebrate retina has ten distinct layers.
- In adult humans, the entire retina is approximately 72% of a sphere about 22 mm in diameter.
- The entire retina contains about 7 million cones and 75 to 150 million rods.
- George Wald, Haldan Keffer Hartline and Ragnar Granit won the 1967 Nobel Prize in Physiology or Medicine for their scientific research on the retina.
- A recent University of Pennsylvania study calculated the approximate bandwidth of human retinas is 8.75 megabits per second, whereas guinea pig retinas transfer at 875 kilobits.