Overview of the Human Eye!
I want to briefly today go over the wall of the human eye. The human eye has a wall that’s made up of three layers: An outer layer, a middle layer, and an inner layer. They each have a different name and a different function. We’re going to go over those briefly.
We’ll begin with the outer layer of the eye wall called the sclera. The sclera is here in the outer wall of the eye, and it is for protection. The cornea, the front of the eye, is actually attached to the anterior portion of the sclera.
Both top and bottom, I’ve only drawn in a representation of the top. The cornea’s job is to refract light that enters from the outside in order to put it through the lens and eventually put it onto the retina to allow vision. The outer part of this 3-tiered system of the wall of the eye is called the sclera.
It’s primarily for protection and anchors and holds the cornea. The middle layer of the eye wall is called the choroid. The choroid’s job is basically to keep the inside of the eye dark. You’re trying to receive light from the outside for vision.
You can’t have light coming in from all sides. It’s got to come through a very narrow and small area. Basically, you’ve got a protective layer, a layer that creates darkness, and then you’ve got an inner layer. This inner layer is called the retina.
The retina, receiving the light coming in through the cornea, is responsible for communicating color to the optic nerve, therefore giving us vision. Within the retina, you’ve got both rods and cones. The rods’ job is to take low-light, colorless environments and help us see.
The cones are for our color vision. I happen to be red/green color deficient. My cones are messed up and I have a very difficult time distinguishing red from green. Christmas tends to be a very boring holiday for me with all these different shades of brown, essentially.
I get asked all the time, “How do you see colors?” It’s hard to describe. I do see colors, but I’m deficient in being able to distinguish reds from greens. They are very similar to me. Anyway, this has just been a basic overview of the eye wall and its three divisions: The outer, middle, and inner, sclera, choroid, and retina.