Definition of Uveitis
Uveitis refers to a group of inflammatory conditions of the eye. In aggregate, uveitis is one of the more common ocular disorders. Uveitis occurs when the inside of the eye inflamed. Uveitis is the fifth or sixth leading cause of blindness in the United States, and probably will affect 3-5% of people sometime during their lifetime.
While some cases have severe symptoms, others can be completely symptom-free, going unnoticed and therefore untreated. Since the uvea borders on all the other vital areas of the eye—including the cornea, retina and sclera--detection is important because it may affect vision if not treated properly.
Types of Uveitis
In most cases, inflammation occurs in two sections of the eye: the iris — which forms the colored part of the eye — and its adjacent tissue, the ciliary body. The ciliary body produces the aqueous humor, which is the normal, clear fluid inside the eye. When one or more of these tissues become inflamed, the uveitis is termed “anterior uveitis,” “iridocyclitis” or “iritis.” The choroid — the vascular lining tissue at the back of the eye between the sclera and retina – provides critical blood flow into the back parts of the eye. When this tissue or the adjacent retina becomes inflamed, the uveitis is called posterior uveitis. Another kind of uveitis is “intermediate uveitis,” involving the pars plana and vitreous in the middle of the eye behind the lens. The name “intermediate” is derived from the location of the inflammation, intermediate between the front and the back of the eye. If all parts of the eye are involved with inflammation, the uveitis is called panuveitis.
Causes of Uveitis
Uveitis may be caused by several different factors and it can be difficult to determine what the cause is. There are many different potential causes, which is what makes it so difficult. Uveitis is often associated with several important systemic diseases, such as arthritis and sarcoidosis. However, about half the time, no specific underlying disease or disorder can be found, and the cases are said to be “idiopathic” (meaning the cause is not known — of course the cause of many of the diseases that “cause” uveitis is not really known either). These “idiopathic” cases probably represent a local autoimmune disease limited to the eye, in which the immune system is attacking part of the eye by mistake.
Most cases of uveitis occur in adults. The risk appears to increase with advancing age. Anterior uveitis is the most common kind of uveitis, and usually the least serious. It can affect one or both of the eyes. In many cases, anterior uveitis can be treated with eye drops and does not return after treatment. Another common pattern is for one eye to be involved at a time, and for attacks to occur first in one eye and then the other, with periods of no activity in between.
Posterior uveitis is usually more serious than anterior uveitis. It may be caused by a virus (such as those viruses that cause shingles, mumps, chickenpox, or herpes), a fungus, or a parasite (such as toxoplasmosis). These infectious agents directly or indirectly attack the choroid or retina, or both. In addition to infections, posterior uveitis also can be caused by autoimmunity, like most other kinds of uveitis. This form of uveitis can be more serious, because it can directly cause retinal scarring, causing vision problems.
Other Varieties of Uveitis
The symptoms of uveitis (if any) vary depending upon the area that is inflamed or affected. The most common symptoms overall are pain, redness, blurred vision, sensitivity to lights (often severe) and seeing spots (‘floaters’). Acute iritis or anterior uveitis is more likely to cause redness, pain, and sensitivity to light. Posterior uveitis and intermediate uveitis can be painless but may cause floaters and decreased vision. Panuveitis can cause any combination of these symptoms.
Another inflammatory eye condition is scleritis. Scleritis is inflammation of the sclera of the eye, the white part of the eye. The sclera forms the major structural component (or outer ‘wall’) of the eye. These tissues also give the eye its white appearance (unless inflamed). Note that the sclera and the adjacent episclera (which also can become inflamed) are located under the conjunctiva but are visible through the conjunctiva.
Diagnosis and Treatment
Proper diagnosis and treatment of uveitis can be complicated because of the variety of causes and locations. A full eye examination is necessary in order to properly diagnose uveitis. The ophthalmologist, depending on the findings, may also ask about a patient’s specific family, social and medical history to determine an underlying cause. You probably will be asked to fill out a questionnaire asking questions about potentially relevant details of your history. Blood tests, skin tests, x-rays and the removal of specimens from the eye (only for the most worrisome cases) may also be helpful in diagnosis.
These steps are used to identify what form of uveitis exists and how it can best be treated. They also help determine whether some previously unrecognized disease might be present, leading to the uveitis. Treatment for iritis (anterior uveitis) usually involves using corticosteroid drops to decrease inflammation and sometimes includes dilating drops to relieve discomfort and prevent scarring. Anterior uveitis can last a few days to a few weeks and may recur even with treatment.
Intermediate uveitis, posterior uveitis, and panuveitis usually are more difficult to treat. Corticosteroids (topical, oral, or injected) or else anti-infectious agents are usually helpful. Immunosuppressive agents may be necessary if uveitis cannot be controlled using simpler methods. Corticosteroid implants also have become available recently, and may be appropriate for some patients. The Scheie Eye Institute also conducts clinical trials evaluating new treatments for uveitis, or comparing the existing treatments to ensure we know which treatment is the best.
If a systemic condition is identified as the cause of uveitis or scleritis, then that condition needs to be treated appropriately. In some cases, treating the systemic condition will help the eye condition as well.
Complications of Untreated Uveitis
If uveitis goes untreated, complications may occur such as:
- Glaucoma, high pressure in the eye
- Cataracts – lens clouding
- Neovascularization, new blood vessel formation
- Retinal damage or detachment
- Optic nerve damage
- Atrophy or shrinkage of the eye
Sometimes high pressure in the eye and cataract occur even with treatment, but these problems usually can be addressed with medical (intraocular pressure) or surgical treatment (both). Other problems usually, but not always, can be avoided by giving appropriate treatment for the uveitis.
Importance of Regular Eye Examinations
Uveitis usually cannot be prevented. However, if you have a systemic condition that is known to be associated with uveitis, regular eye examinations are particularly important. This is especially true for patients with juvenile idiopathic arthritis, who often have no symptoms and often are too young to complain of poor vision until much of the treatment opportunity is lost. Prompt treatment of the uveitis is important to limit the damage to the eye and increase the chance of a positive outcome.
The symptoms of uveitis are very nonspecific, so an eye examination is necessary for patients with uveitis who have any unusual eye symptoms, such as changes in vision, pain, double vision, light sensitivity, etc.
The Ocular Inflammation Service at the Scheie Eye Institute, directed by Dr. John Kempen, provides comprehensive management and consultation for patients with uveitis, as well as providing access to clinical trials of new treatments for uveitis that are being developed. Drs. Alexander Brucker and Albert Maguire also are expert in the diagnosis of uveitis, particularly uveitis involving the back of the eye.