Electromagnetic Spectrum |
The retina of each eye contains receptor cells responsible for vision. These receptor cells are called Rods and Cones. These cells are sensitive to only a fraction of the spectrum of electromagnetic energy. The retina of each eye contains approximately 120 million rods and 6 - 8 million cones. Rods respond to the intensity of light and cones allow us to see color as well as light and dark.
The photo receptor cells (rods & cones) connect to bipolar cells and ganglion cells of which the axons form the optic nerve. In the fovea, cones generally have a 1:1 connection with bipolar cells, this direct connection to the brain allows for the brain to pick up on fine details this is known as visual acuity. In other areas of the retina the data from many receptors are connected to one bipolar cell. This is why peripheral vision is somewhat blurred. This pooling of information does not assist with fine detail but is helpful in low light situations where the stimulus to each individual receptor is low. |
Intro Rods & ConesThis video has a quick review of anatomy but also adds information on location and function of Rods & Cones. Add new information to notes.
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Rod/Cone DensityThis video does a very good job of explaining distribution of rods and cones on the retina and the impact of this distribution on visual acuity.
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Helpful ImagesThese diagrams and images should help you get a concrete understanding of the retinal area. Remember you can zoom in by hitting control and scrolling.
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