How does the eye transform light energy into neural messages?

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afagnano eNotes educator| Certified Educator

Our eyes belong to a special set of eyes called "camera-type eyes". Light comes in via our lenses and focuses on a light-sensitive membrane in the back of the eye called the retina. This works similarly to how a camera focuses light onto film, thus the name. 

The retina is made up of millions of light sensitive cells. These cells come in two varieties: rods and cones. Cones are used for seeing color and fine details, while rods are used for vision in poor lighting. Rods are found more towards the outside of the retina, while cones can be found in the center of the eye. When light strikes these cells, it excites them into sending electrical signals through the optic nerve to the brain. 

It is not yet fully understood how exactly our brains process these messages into images, but the most recent research suggests that there are three different processing centers in the brain. One works with shape, one deals with color, and the last is responsible for spatial location and movement. These can all be found in the primary visual cortex, which is in the back of the brain (occipital lobe).