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Our eyes are the doorway to the external environment, and clearly, the most important of the sense organs. They play a pivotal role in our day-to-day existence. The eye receives light from the outside world, and converts it into electrical signals that are transported to the brain and perceived as an image. The eye is a slightly asymmetrical globe, about an inch in diameter.


Main Parts of the Human Eye

Sclera: The sclera is the white part of the eye that surrounds the cornea. It is made up of fibrous tissues, and provides protection to the inner parts of the eye. This is the tissue that is commonly called the white of the eye.

: The cornea is the transparent tissue at the front of the eyes through which light coming from an object enters the eye. It also helps in focusing the light on the retina.

Aqueous Humor: It is a clear transparent fluid that fills the space between the cornea and the eye lens. It also supplies nutrients and oxygen to these parts.

Iris: The iris is a ring of muscles in the central part of the eye, that is helpful in regulating the amount of light entering the eye by controlling the size of the pupil.

Pupil: This is an opening in the center of the iris through which light passes and falls on the eye lens. Its size is controlled by the iris.

Eye Lens: The lens of the eye is situated directly behind the pupil. It helps in focusing the light on the retina. The eye lens is capable of changing its shape so as to enable us to see objects near and far.

Ciliary Muscles: This is a ring-shaped tissue that holds and controls the movement of the eye lens, and therefore, helps in controlling the shape of the lens.

Vitreous Humor: It acts as a filler and covers the space between the eye lens and retina. It also provides protection to the lens. It makes up for about two-thirds of the total volume of the eye, and is composed mainly of water.

Retina: It is a membrane responsible for converting the light falling on it into electrical impulses that can be sent to the brain. The retina contains light-sensitive photoreceptor cells called rods and cones. The rods help in black and white vision and for seeing in dim light, while the cones help in daytime and color vision.

Optic Nerve: It is a bundle of nerve fibers that serve as a cable that connects the eye to the brain. This optic nerve helps in transmitting signals from the retina to the visual center of the brain.

Yellow Spot or Macula: Situated at the center of the retina, this yellow spot helps in absorbing excess light that enters the eye. The macula is responsible for our reading vision, and helping us to see objects right in front of us.

Eyelids: The eyelids help in the protection and lubrication of our eyes. They also help in controlling the amount of light falling onto our eyes.

Muscles of the Eye: The eyeball is held in its place by the help of several eye muscles. The eye muscles are responsible for the up and down, as well as the left and right movement of the eye.

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