Human Eye Anatomy - Outer Parts of the Eye and It's Functions

The eye is the most important organ of the body and nervous system used for seeing. The human eye is like a camera having an adjustable opening to let in the light (the pupil), a lens which focuses the light waves to form an image and the retina, which acts like a sensitive film on which the image is recorded.

Parts of the Eye and Functions

Some of the most important parts of the eye and its activities in the body are shown in this short article. The eye anatomy described all external and internal parts of the eye. As an eye specialist, he has to know all about these parts identification and functions exactly in details. Because each part has most impotence. Today I am going to share with you my simple study of the human eye structure in this content. The eye structure consists of the following parts:

1. Sclera:
   A strong membrane which surrounds the entire eyeball. In fact, the whites of the eye are parts of the sclera.
2. Choroids:
   A layer which is beneath the sclerotic layer and contains black pigmentation to prevent reflection within the eye. It has plenty of blood vessels for supplying the eye with oxygen and food.
3. Retina:
   It is the inner layer (containing nerve cells which are sensitive to light) of the eye and acts like a screen on which the image is recorded. It has two types of cells, viz. Rods (sensitive to low-intensity light) and Cones (sensitive to bright light) and is responsible for color vision. In fact, a small area of the retina called fovea at the back of the eye has only cones but no rods and gives the fair degree of detail of color.


4. Blind Spot:
   It is the part of the retina where the nerve fibers, which are connected with cones and rods leave the eye and enter the optic nerve.
5. Humor Fluids:
   These are of two types, the aqueous humor and vitreous humor contained in the eye and help to maintain the shape of the eye and allow nutrients and wastes to diffuse into and out of the eye cells.
6. Lens:
   It is a transparent biconvex structure and can change its curvature and is basically responsible for focusing light on the cells of the retina.
7. Suspensory Ligaments:
   These are attached to ciliary's muscles and keep the lens in position.
8. The Iris:
   It controls the amount of light entering the eye.
9. Pupil:
   It is a hole in the center of the iris through which light enters and protects the retina from possible damage. When the light is poor, the pupils get dilated and remain wide open to allow maximum amount of light into the eye. However, if the light is brighter, the pupil contracts (becoming smaller) and thus prevents the retina from any possible damage.

Picture with Various Parts of Eye

A diagrammatic representation of the various parts of eye is shown in the image of this post.

Human Eye Diagram & Functions

The image produced on the retina is upside down or inverted. This is corrected by the brain.

There are two common imperfections in the eye. These are long sightedness (near vision) and short sightedness(far vision). In the next post, I will share with you my study on long sightedness and short-sightedness including the best consultation and treatment.

A person with long sight cannot see close objects clearly because the light focuses behind the retina. This can be corrected by wearing a convex lens.

On the other hand, a person with short-sightedness (far vision) (myopia) cannot see distant objects clearly because the light focuses in front of the retina. This can be corrected by wearing a concave lens.

The eye has a natural mechanism to protect itself. The eyelids blink about 20 times a minute. These bathe the eyeballs and wash away the dust with the help of the tears which come out automatically as a reflex action.

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