Parts of the Eye
Although the eye is a small structure, it is extremely complex and contains an immense network of nerves, blood vessels, cells and specialized tissues.
To understand how the eye operates, it is first necessary to know the names and functions of some of its parts.
The clear, transparent front portion of the fibrous coat of the eye; functions as an important refractive medium.
The tough white protective coat of the eye. The portion of the sclera that surrounds the cornea is covered by the conjunctiva.
A mucous membrane extending from the eyelid margin to the corneal limbus, forming the posterior layer of the eyelids and the anterior layer of the eyeball.
A colored, circular membrane suspended behind the cornea and immediately in front of the lens. It regulates amount of light entering the eye by adjusting size and pupil.
The opening at the center of the iris of the eye; it contracts when exposed to strong light or when the focus is on a near object and it dilates when in the dark or when the focus is on a distant object.
Watery liquid that flows between the lens and the cornea and nourishes them.
The transparent tissue behind the iris that bends light rays and focuses them on the retina.
Schlemm's Canal (Schlemz ke'nal)
A passageway for the aqueous fluid to leave the eye.
Vitreous body (vit're-us)
Transparent, colorless mass of soft, gelatinous material that fills the center of the eye behind the lens.
Light-sensitive tissue at the back of the eye which transmits visual impulses via the optic nerve to the brain.
Pigmented central area or "yellow spot" of the retina devoid of blood vessels. It is the most sensitive area of the retina and is responsible for fine or reading vision.
Blood vessel-rich tissue behind the retina that is responsible for its nourishment.
Optic nerve (op'tick nurv)
The nerve at the back of the eye that carries visual impulses from the retina to the brain. The area at which the optic nerve connects with the retina is known as the optic disc.
The Mechanics of Sight