Encyclopedia - Iritis

When does iritis occur?
How does iritis appear?
How is iritis diagnosed and treated?

Iritis is an inflammation of the iris, the colored part of the eye that controls the size of the pupil opening (See Anatomy of the Eye). The condition is relatively common and responds well to treatment, but it can be sight-threatening if left untreated. It is not uncommon for patients to have multiple episodes of iritis even with prompt, proper treatment. Usually, only one eye is affected at any one time, but the condition can occasionally occur in both eyes.

The iris, which contains two muscles, controls the size of the pupil opening. In dim light or at night, the iris makes the pupil larger to increase the amount of light entering the eye. When too much light is present, the iris causes the pupil to become smaller to reduce excessive light and glare.

When does iritis occur?

Most often, the cause of iritis is unknown, although it can be associated with other inflammatory conditions of the body such as arthritis. Infection of some parts of the body -- especially the tonsils, sinuses, kidney, gallbladder, and teeth -- can also cause inflammation of the iris. On occasion, iritis can occur following an eye injury or can accompany an ulcer or foreign body on the cornea.

How does iritis appear?

Symptoms of iritis often appear suddenly and develop rapidly over a period of several hours or days. The condition commonly causes pain, tearing, light sensitivity, blurry vision, and, in some cases, red eye. Some patients also experience floaters, which are small dots or flecks that seem to float in the field of vision. The pupil in the affected eye may also become smaller.

How is iritis diagnosed and treated?

See your eye doctor for an examination when symptoms of iritis occur. The most useful tool in diagnosing iritis is the slit lamp, a table top microscope that illuminates and magnifies the various structures of the eye. You may also need a complete medical examination because the condition is sometimes associated with another disease.

Iritis usually responds well to treatment. Eyedrops and ointments relieve pain and inflammation, dilate the pupil, and reduce the possibility of scarring. Dilating eyedrops relax the irritated iris, decreasing the discomfort and preventing the inflamed iris from sticking to the lens. In some cases, both steroids and antibiotics are prescribed. Hot compresses may also provide some relief. Severe cases are treated with oral medications and injections. Iritis usually lasts from six to eight weeks. Cataracts, glaucoma, corneal changes, and secondary inflammation of the retina can result from iritis and the medications used to treat the disorder, so careful monitoring is important.

Iritis can be sight-threatening, therefore proper diagnosis and prompt treatment are essential. As soon as symptoms occur, a complete eye examination is necessary so that the condition can be controlled before any vision loss occurs. The sooner treatment is begun, the easier it is to treat.