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The uvea is the pigmented middle layer of the three concentric layers that make up the eye. The words comes from the Latin word for grape, and it is thought the name is given because, when dissected from the eye, the uvea looks like a wrinkled, purple grape skin. The uvea has three main parts: the iris, ciliary body and choroid.
The iris is the most visible part of the uvea. It is the uniquely pigmented part of the eye that gives it color. If the iris is brown, a person is said to have brown eyes, for example. The iris expands and contracts around the pupil to control the amount of light being admitted into the eye.
The ciliary body is the structure in the eye that releases a transparent liquid (aqueous humor) within the eye, that helps keep the eyeball free of debris. The ciliary body of the uvea has the ciliary muscle, which changes the shape of the lens as the eyes focus on an object. The choroid is the layer of blood vessels and connective tissue between the sclera (white of the eye) and retina. It supplies nutrients and oxygen to the inner parts of the eye. The uvea as a body also improves the contrast of the retinal image by reducing reflected light inside the eye.
The eye as a whole is sensitive to irritation and can become easily inflamed. Uveitis is an inflammation of the uvea and can hinder sight significantly. There are many causes of uveitis, including syphillis and toxoplasmosis. It should be treated as soon as possible, so the person will not lose his or her sight. When treated promptly, the prognosis is usually good and the recovery uneventful. Prednisone drops are the treatment of choice for uncomplicated uveitis. If inflammation is suspected due to infection, a course of antibiotic drops may also be prescribed.
The uvea is a complex structure, critical to proper eye function. Anyone suffering inflammation or pain in the eye should always seek medical treatment for the condition. He or she might not have uveitis, but keeping the uvea healthy is a key to maintaining good eyesight.