Iritis, also known as anterior uveitis, is an inflammation of the iris (the colored part of the eye surrounding the pupil) and the ciliary body (the part of the eye that produces the fluid that fills the eye). It is one of the most common types of uveitis, which is an inflammation of the uvea, the middle layer of the eye.

The exact cause of iritis is often unknown, but it can be associated with autoimmune disorders, infections, trauma, or exposure to certain medications or chemicals. It can also be a complication of other conditions, such as arthritis or inflammatory bowel disease.

Symptoms of iritis may include eye pain, redness, sensitivity to light (photophobia), blurred vision, and a small or irregular pupil. The symptoms can come on suddenly and may affect one or both eyes.

Diagnosis of iritis typically involves a thorough eye exam, which may include an examination of the eye's interior using a special instrument called a slit lamp. Additional tests, such as blood tests or imaging studies, may be ordered to determine the underlying cause of the inflammation.

Treatment for iritis may depend on the underlying cause, but it often involves anti-inflammatory medications such as corticosteroids or non-steroidal anti-inflammatory drugs (NSAIDs) to reduce inflammation and relieve symptoms. Other medications or treatments may be used to address any underlying conditions or complications.

If left untreated, iritis can lead to complications such as glaucoma, cataracts, and vision loss. It is important to seek prompt medical attention if you experience symptoms of iritis, especially if they are severe or persistent. With appropriate treatment, most cases of iritis can be effectively managed and complications can be prevented.

Often, the cause of iritis can't be determined. In some cases, iritis can be linked to eye trauma, genetic factors or certain diseases. Causes of iritis include:

• Injury to the eye. Blunt force trauma, a penetrating injury, or a burn from a chemical or fire can cause acute iritis.
• Infections. Viral infections on your face, such as cold sores and shingles caused by herpes viruses, can cause iritis.
• Infectious diseases from other viruses and bacteria can also be linked to uveitis. For instance, they may include toxoplasmosis, an infection most often caused by a parasite in uncooked food; histoplasmosis, a lung infection that occurs when you inhale spores of fungus; tuberculosis, which happens when bacteria enters the lungs; and syphilis, which is caused by the spread of bacteria through sexual contact.
• Genetic predisposition. People who develop certain autoimmune diseases because of a gene alteration that affects their immune systems might also develop acute iritis. Diseases include a type of arthritis called ankylosing spondylitis, reactive arthritis, inflammatory bowel disease and psoriatic arthritis.
• Behcet's disease. An uncommon cause of acute iritis in Western countries, this condition is also characterized by joint problems, mouth sores and genital sores.
• Juvenile rheumatoid arthritis. Chronic iritis can develop in children with this condition.
• Sarcoidosis. This autoimmune disease involves the growth of collections of inflammatory cells in areas of your body, including your eyes.
• Certain medications. Some drugs, such as the antibiotic rifabutin (Mycobutin) and the antiviral medication cidofovir, that are used to treat HIV infections can be a rare cause of iritis. Rarely, bisphosphonates, used to treat osteoporosis, can cause uveitis. Stopping these medications usually stops the iritis symptoms.

Iritis treatment is designed to preserve vision and relieve pain and inflammation. For iritis associated with an underlying condition, treating that condition also is necessary.

Most often, treatment for iritis involves:

• Steroid eyedrops. Glucocorticoid medications, given as eyedrops, reduce inflammation.
• Dilating eyedrops. Eyedrops used to dilate your pupil can reduce the pain of iritis. Dilating eyedrops also protect you from developing complications that interfere with your pupil's function.

If your symptoms don't clear up, or seem to worsen, your eye doctor might prescribe oral medications that include steroids or other anti-inflammatory agents, depending on your overall condition.