Iritis is inflammation of the iris, the pigmented structure that makes up the colored part of the eye. The iris is primarily composed of smooth muscle and it controls the size of the pupil. Iritis is also called anterior uveitis, because the iris is located in the front of the middle region of the eye, which is known as the uvea. Iritis is the most common type of uveitis.
Iritis can be caused by many different underlying conditions, but much of the time it may not be possible to determine the cause. Iritis can be caused by infections in some cases, especially viral infections such as herpes zoster (shingles). People with certain autoimmune diseases, such as juvenile rheumatoid arthritis or ankylosing spondylitis may also develop anterior uveitis. Iritis may also be caused by trauma to the eye or eye burns caused by chemical exposure or heat. Uncommonly, iritis may be a side effect of certain medications, including some antibiotics and some antiviral medications.
The symptoms of iritis include eye redness, especially right around the iris of the eye; a sore or dull aching painful feeling in the eye; blurred vision; light sensitivity and floaters in the visual field. Iritis can be acute or chronic, with chronic iritis lasting for over six weeks. Chronic iritis that goes untreated is linked to other eye conditions, such as scarring of the iris that leads to an irregularly-shaped pupil, cataracts, glaucoma, formation of calcium deposits and inflammation of other parts of the eye. Anyone experiencing eye pain should be examined and treated by a medical professional to prevent complications and possible permanent vision loss.
The main treatments for anterior uveitis are medicated eye drops. Glucocorticoid eye drops help decrease inflammation in the iris of the eye. Antibiotic eye drops may be prescribed for certain types of eye infections that can cause uveitis. Medicated eye drops that dilate the pupil may also be given because they prevent the inflamed iris from adhering to other structures in the eye and reduce the eye pain involved with iris inflammation. Severe cases of iritis that do not respond to these treatments may be treated with oral medications, such as corticosteroids, that systemically reduce inflammation. These drugs are not the first line of treatment because they may have systemic side effects that local medications do not, but if a person’s vision is in danger, the benefits of these treatments may outweigh the risk.