Iritis / Anterior Uveitis
Iritis is an inflammation of the iris, which is the colored circle in the front of the eye. Uveitis is a more encompassing term describing inflammation of the uveal tract, of which the iris is a part. The other parts of the uveal tract are the trabecular meshwork and ciliary body in the front of the eye, and the choroid which extends to the back of the eye under the retina.
The most practical way of thinking about the symptoms, causes, and treatments of this condition is to subdivide uveitis into anterior – those inflammations that involve primarily the front of the uveal tract (iris, trabecular meshwork, and ciliary body) – and posterior – those that involve the pars plana and choroid. Your doctor can tell what structures are involved by examining the eye.
The focus of this discussion will be anterior uveitis, because that will be the diagnosis of most people accessing this website. Posterior uveitis has a wider variety of causes, systemic associations, and possible treatments. Most people with posterior uveitis should seek the help of a retina or uveitis specialist for further diagnosis and treatment.
What are the symptoms of anterior uveitis?
Anterior uveitis (which includes iritis) usually causes pain, sensitivity to light, blurry vision, and redness. Interestingly, some people will have little to no symptoms, which sometimes delays the diagnosis. For example, children with juvenile rheumatoid arthritis (JRA) usually do not have any eye symptoms. Regular screening eye examinations are recommended for these children.
What are the causes of anterior uveitis?
Uveitis has several possible causes. Broadly speaking, autoimmune disease is by far the most common, but infections, tumors, and trauma are other possible rarer causes. These will be discussed further.
Autoimmune disease means the body’s immune system is inappropriately attacking itself. In this case, it’s attacking the uveal tract. Autoimmune disease is a very common class of human diseases. Some well known autoimmune diseases include rheumatoid arthritis, where the immune system inflames the joints, and psoriasis, where the immune system inflames the skin. Most people with autoimmune anterior uveitis actually don’t have a systemic autoimmune disease, but rather have a localized autoimmune dysfunction involving the uveal tract. With that being said, however, anterior uveitis may be a clue to a systemic autoimmune condition, so several diseases should be considered in a person with anterior uveitis. The most common systemic autoimmune association of anterior uveitis in adults (in this country) is a group of disorders called the HLA-B27 spondyloarthropathies, some of which include ankylosing spondylitis, inflammatory bowel disease, and psoriatic arthritis. Other common autoimmune associations would include sarcoidosis, lupus, and rheumatoid arthritis. The list of possible associated conditions is long.
A less common cause of anterior uveitis is infection. The most common infections are those caused by the herpes class of viruses (like herpes simplex, varicella zoster, and mumps). Very rare causes would include Lyme’s disease and syphilis. There are other infectious causes of posterior uveitis that can spill-over to the front of the eye, but a thorough eye examination should be able to rule-out a posterior cause of a person’s uveitis, including a neoplastic process like lymphoma or juvenile xanthogranuloma.
What is the work-up? What tests should I have?
The most important part of the evaluation is old-fashioned talking with the patient (what doctors call “the history”) and an eye examination. In most situations of anterior uvietis, this is all that is required. The symptoms or conditions in which the doctor may be interested include low back or other joint pains, unexplained rashes, past blood clots or miscarriages, exposures to ticks or sexually transmitted diseases, recurrent red eyes that haven’t been evaluated by an eye doctor, gastrointestinal symptoms, ulcers of the mouth or genital area, past glaucoma surgery, penetrating trauma to this or the other eye, shortness of breath, other known autoimmune diseases, active chronic infections (like tuberculosis), or past cancers. On the eye examination, there are occasionally characteristic signs of the uveitis that give a clue to an underlying association.
If the doctor uncovers symptoms or sees characteristic findings on the examination, or if the uveitis is recurrent, further laboratory blood tests may be ordered to determine an underlying cause. Further evaluation by a uveitis or retina specialists, or a rheumatologist may be recommended.
What is the treatment of anterior uveitis?
The most common treatments are topical steroids and dilating drops. If the uveitis does not respond adequately to topical therapy, then injections of steroids around the eye, or steroid pills by mouth (like prednisone) may be recommended. Therapy may also be governed by an underlying cause of the uveitis, if one is found. An example of this would be oral antiviral pills if a herpes virus is suspected. Glaucoma (high eye pressure) may accompany uveitis, in which case pressure lowering drops may be recommended. Severe or recurrent uveitis may cause other eye diseases, most commonly a cataract or glaucoma, that would require specific medical or surgical therapy. It would not be uncommon for a bout of anterior uveitis to require 6-8 weeks of therapy before the condition resolves.
Can anterior uveitis come back? Can I go blind?
Although some patients may have only one attack of uveitis, it may recur. Some patients can have frequent recurrences , perhaps several times a year. Recurrences can also be quite infrequent, separated by years or decades. A small subset of people, often those with an underlying cause, will have chronic uveitis requiring ongoing therapy. Some patients may develop glaucoma that may require ongoing eyedrop therapy or surgery. Sometimes a cataract may develop that would require removal. Even with frequent recurrences, appropriate and timely therapy can prevent most complications that would lead to permanent vision loss. Only a small subset of patients with anterior uveitis will have a clinical course severe enough to have permanent vision loss.