The Importance of Eyes

Vision is one of the most important sense human beings have. According to recent surveys, people fear to lose their visual sense more compared to all other senses. Living without eyes would be very difficult for humans. The eye is composed of many parts, each with different functions. There are eye parts responsible for allowing light to enter the eye, while other parts of the eye play a role in the protection of the eye.

Main Parts of the Eye

1. Cornea

The cornea is the clear layer at the front of the eye. It is so transparent that one may not realize that it is there. It is in the front of the iris which is actually a colored part of the eye. Its main function is to focus the light which enters the eye. If you are wearing contact lens, then the lens rests on the cornea.

2. Iris

Iris has a ring of muscle fibers around the pupil that can contract, causing the pupil to become smaller. This happens in bright light. There is a second set of muscle fibers as well which radiate outward from the pupil. When these fiber muscles contract, the pupil becomes larger and this happens in reduced darkness or illumination. It is responsible for controlling the size and diameter of the pupil and the amount of light which is reaching the retina.

3. Pupil

The pupil is a hole in the center of the iris of the eye which allows the light to enter the eyeball and strike the retina. Its color is black due to the light rays entering being absorbed by the tissues in the eye directly.

4. Ciliary muscle

This muscle is made up of water and proteins. It is a transparent body and enclosed in an elastic capsule. This muscle has layers like an onion. It also becomes more yellow with the passage of age. Its function is to tighten or relax the zonules which then enables the lens to changes the shape for focusing.

5. Sclera

The sclera is the white part of the eye which you can see while looking at yourself in the mirror. The sclera is leather-like, tough tissue which extends around the eye. It is like an eggshell and surrounds the complete eye and gives it a proper shape. Its function is to protect the eye.

6. Optic nerve

The optic nerve is a bundle of more than 1 million nerve fibers. It is responsible for transmitting the nerve signals from the eye to the brain. These signals of the nerve have all the information for processing by the brain. The surface of the nerve which is visible on the retina is known as the optic nerve head.

7. Retina

The retina is acting like a film in the camera to create an image. Chemical reactions occur inside the retina when a focused light strikes the retina. As a result of these chemical reactions electrical signals are produced which are transmitted through the nerve cells into our optic nerve and carries the signals to the brain where the electrical signals are converted in the images which can be recognized. These visual association areas of our brain process the signals to make them understandable with the correct context of the image.

There are two types of cells which initiate the chemical reactions. The two types of cells are rods and cones. Rods are sensitive to light and allow you to see in low light but they will not help you to see colors. On the other hand, cones allow you to see color and require more light.

8. Fovea

The location for the central gaze on the retina is fovea. When you are looking directly at a stimulus, the center of the fixation is your fovea. The nerves there are very tightly packed, thinner and elongated. It is used mainly for color vision and has the highest visual acuity.

9. Choroid

The choroid is also a layer of tissue which lies between the sclera and the retina. The choroid is made up of the blood vessels. They actually help to nourish the retina of the eye.

10. Orbit

Orbit is the eye socket in the skull. It is formed by the forehead, cheekbone, the temple and the side of the nose. Fat is used for the support of the eye within the orbit. The orbit also contains muscles that help in moving the eye, nerves and the blood vessels. The orbit also contains a gland named lacrimal which is located under the outer portion of the upper eyelid. This gland produces tears which help to lubricate and moisten the eye and flush away all the foreign matter which can enter the eye. The tears produced by the lacrimal gland drain away using the nasolacrimal duct which is located at the inner corner of the eye.

Parts to Protect Eyes

1. Eyelid

Eyelids protect the eye from all the foreign matter. All the particles of dust, dirt and other debris stay away from the eyes due to the eyelids. It also saves the eye from the bright light which may damage the eye. Eyelids also help in spreading the tears over the surface of an eye when you blink and keep the eye comfortable and moist.

2. Vitreous

It is located behind the lens and in front of the retina. It has a gel-like fluid which is called vitreous humor. It also helps in maintaining the shape of the eye.

3. Conjunctiva

This is a thin and transparent layer of tissues covering the front of your eye which includes the inside of the eyelids and sclera as well. It keeps away all the bacteria and other foreign material from the eye. It contains visible blood vessels which are visible against the white background of the sclera.

Conclusion

Eyes are indeed very important for human beings. Different parts of the eye have different functions and together they help us visualize different things. Even a minor problem in any part of the eye can cause serious vision problems so you need to take proper care of your eyes. You can have more insight about parts of the eye after watching this video.