What is the optic nerve? The optic nerve is responsible for getting information from your eye to your brain! Keep reading to find out how this nerve functions
How Does the Optic Nerve Work?
Even though the optic nerve is located in your eye it is part of your central nervous system. The optic nerve takes visual information gathered from your eye and transmits it using a series of electrical impulses to the parts of your brain that act as vision centers. Each optic nerve is a bundle of more than one million nerve cell fibers (specifically, Retinal Ganglionic Cells or RGCs) that work together to help you see. Since where the optic nerve exits your eye there are no photoreceptors this is also what we know as your blind spot.
In the retinal tissues of the eye, more than 23 types of RGCs vary significantly in terms of their morphology, connections, and responses to visual stimulation. Those visual transmitting RGCs are the neuronal cells. They all share the defining properties of:
- Possessing a cell body (soma) at the inner surface of the retina.
- Having a long axon that extends into the brain via the optic chiasm and the optic tract.
- Synapsing with the LGN. The RGCs form multiple functional pathways within the optic nerve to mediate the visual signal
Human beings can see three primary colors: red, green, and blue. This is due to our having three different kinds of color sensitive cone cells: red cones, green cones, and blue cones.
The RGCs connecting to the red and green cones are midget RGCs. They are primarily located at the center of the retina (known as fovea). A single midget RGC communicates with as few as five photoreceptors. They transmit these red-green color signals to the parvocellular layer in the LGN. The midget-parvocellular pathway responds to color changes, but has little or no response to contrast change. it is because of this pathway, we can see objects precisely in detail and in full color.
Finally, we can see objects in three-dimension thanks to the crossing over of optic nerve fibers at the optic chiasm. This anatomic structure allows the human visual cortex to receive the same hemispheric visual field from both eyes making it possible for us to generate binocular and stereoscopic vision.
Visit us at Schmidt’s Optical and Hearing™ in Stuart FL and see any of our experienced opticians about your visual needs.