Did you know that lining the back of your eye is a thin membrane—only .5 to 1 mm thick—with profound implications for your ability to see the world around you? Despite its small size, this membrane, known as the retina, is a crucial tool for sending messages to the brain to help us process what we see!
Parts of the Retina and How They Work
In order to understand how important this complex layer of thin tissue truly is, it is essential to understand how it works. Much like the film in an old camera processes light as an image, the retina is responsible for translating the light around us into nerve signals. By catching and interpreting these signals, the brain uses the human eye to interpret color and detect images, even from a distance away.
The retina is made up of a few elements that help with this process:
- Photoreceptors: Known as cones and rods, these are elongated retinal cells that work like an antenna, gathering the light that hits the layer of thin tissue lining. After this, an intense biochemical process fueled by a healthy amount of vitamin A changes the light into electrical signals that send messages to the brain. In this process, cones provide people with the ability to discern details such as objects and colors, while rods help us interpret light intensity and allow for night vision.
- Fovea: This region, at the back of the retina, is a tiny depression in the human eye. This single point works to give humans the best perception of color, as well as the sharpest vision, which is why it needs to be maintained for optimal eye health.
- Optic nerve: This portion of the eye is a bundle of fibers that carries signals to the brain. Attached to the back of the eye, these bundled nerves cause a natural “blind spot,” or a tiny point on the retina that is insensitive to light. This leaves us with a small, almost unnoticeable gap in our vision where we are essentially blind—however, our brains work to compensate for this blind spot, so you might not notice it from day to day.
The optic nerves work to transfer visual information from the retina to the vision centers of the brain through electrical impulses. The optic nerve is actually made of ganglionic cells and consists of more than a million nerve fibers. While part of the eye, the optic nerve is also considered to be part of the central nervous system.
Potential for Damage
Damage to the retina can happen in many different ways. The most common cause of blindness in the US in people over the age of 65 is macular degeneration, or a consistent, slow loss of vision.
Those with a vitamin A deficiency may also see minor damage to the retina. Because vitamin A is used to develop photopigment in the photoreceptors of the eye, this deficiency can lead to the loss of peripheral and night vision over time.
In addition, retinal detachment can occur when the retina is disconnected from the back of the eye; this can be caused by an injury to the eye or, in some cases, by severe nearsightedness. If you find yourself victim to retinal detachment, the only way to restore eye health in this event is surgery to reattach the lining to the back of the eye.
For more information about the retina’s role in your vision, or how to minimize the risk of damage, reach out to our office with questions. We’d love to hear them!