Anterior Chamber
The space between the cornea and the iris which is filled with fluid aqueous.
Chamber Angle
The structure formed by the junction of the iris with the corneo-sclera. Normal fluid drainage from the eye occurs through the trabecular meshwork which lies in the chamber angle. Malfunction of the chamber angle is the cause of glaucoma (high pressure in the eye).
Choroid
A spongy layer filled with blood vessels. It lies between the sclera and the retina. The choroid nourishes the outer layers of the retina.
Ciliary Body
A ring of tissue lying at the base of the iris. Its muscle fibers serve to change the curvature of the lens and thereby provide fine focusing of light onto the retina.
Cornea
The clear front window to the eye. It is the most important part of the focusing system of the eye and brings objects into focus on the retina.
Iris
The colored tissue behind the cornea - color varies from pale blue to dark brown.
Lens
A clear biconvex structure behind the iris which works in conjunction with the cornea to focus light onto the retina. When the lens becomes opaque or cloudy, it is called a cataract.
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Macula
The highly developed central zone of the retina. The macula gives critical vision for reading and discrimination of small objects.
Optic Nerve
A cable-like structure composed of thousands of nerve fibers which carry impulses from the retina to the brain where visual perception occurs.
Pupil
The round hole in the iris. Its size is automatically varied to regulate the amount of light entering the eye.
Retina
The vital thin layer of tissue composed of millions of visual cells which lines the inside back two-thirds of the eye. The retina is analogous to a film in a camera. It receives light and sends tiny electrical impulses to the brain to give sight.
Sclera
The white, tough protective outer wall of the eye.
Vitreous
The clear jelly which fills the space between the lens and the retina. Eighty percent of the eye is filled with vitreous.
Zonules
Threadlike filamentous attachments which hold the lens in place in the eye.
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