What happens when we look at shapes, try to find out how far away something is, notice movement and color? What is happening is that we are seeing. The eye is the organ that helps us to see, but the eye does not work on its own to make this happen.
|Parts of the Human Eye|
The eye is a ping pong shaped organ that works with the brain and with light in order to help us to see. The eye has three different layers, the outer layer, the middle layer and the inner layer. These three layers work with light to make us see the world around us.
In the outer layer, there is the sclera and the cornea. The middle eye consists of the ciliary body, the iris and the choroid and the inner eye contains the retina.
In order for us to be able to see, we must have light. When light goes on an object, the light is reflected and directed back to your eyes. Then, travelling through the pupil, the light passes through the lens. The lens is like the lens on a camera, it helps to make the image look clearer.
The lens turns the image upside down, or inverts it, and all of this happens without us knowing it. The image is then displayed in the retina and is inverted back upright because the rays are bent, and they cross each other.
The retina is a very important part of the eye. The retina is made up of tissues that have photoreceptors, also called optic nerves. These nerves help the body to detect light.
The optic nerve is responsible for taking the take the inverted image to the brain so that the brain can interpret the image and tell what the image is. This happens faster than you can blink. When the optic nerve inverts the image, this is called impulse.
The retina is made up of two different types of nerve cells called the rods and the cones. Rods are sensitive to the dark and they are responsible for helping us to see when it is dark outside or inside.
Cones are what helps us to see color. The cones are special cells that help us to see red, blue and yellow and then the cone nerve cells are able to change these three colors into hundreds and even millions of other colors. The cone nerve cells never stop working.