Uveitis

What Is It?

Uveitis is a general term referring to an inflammation of a portion or all of the part of the eye called the uvea. The uvea, also called the uveal tract, is a continuous layer of fibrous tissue that surrounds the eye. It is made up of three structures:

• The iris — The donut-shaped part that gives the eye its color, visible when you look someone in the eye.
• The choroid — A membrane full of tiny blood vessels that lines the eye.
• The ciliary body — A thick ring of tissue that helps control the shape of the lens. It is attached to the iris and to the front portion of the choroid.

Various terms are used for the condition, depending on the part of the uvea affected. They include:

• Anterior uveitis (iritis) — Affects the front portion of the uvea, the iris
• Iridocyclitis — Affects the iris and the ciliary body
• Intermediate uveitis (cyclitis) — Affects the middle portion, the ciliary body
• Posterior uveitis (choroiditis) — Affects the back part of the uvea, the choroid
• Diffuse uveitis — Inflammation of all portions of the uvea

The most common types of uveitis are anterior uveitis and iridocyclitis. Posterior uveitis is rare. Although the exact mechanism that causes the uvea to become inflamed is unknown, many cases are related to an autoimmune disorder (such as ankylosing spondylitis, juvenile rheumatoid arthritis, or sarcoidosis ) or an infection, such as toxoplasmosis, herpes, syphilis, or cytomegalovirus (especially among patients with AIDS). In up to half of cases, the cause is not known.

Symptoms

Symptoms of uveitis can vary depending on the location of the inflammation. Severe symptoms generally are associated with anterior uveitis, and can include:

• Eye pain
• Eye redness
• Sensitivity to light
• Blurred or decreased vision

Intermediate and posterior uveitis can have more subtle symptoms, including small specks or clouds that move in your field of vision, called floaters, and decreased vision.

Diagnosis

If your physician suspects uveitis, you are likely to be referred to an ophthalmologist (eye specialist). A thorough eye exam is given, including:

• Tests of visual acuity, to determine if vision has decreased. This can be as simple as reading an eye chart.