|Uveitis affects the middle layer or uvea. At the front of the eye, this refers to the iris and the ciliary body. In the center and back, it refers to the choroid, the tunic of blood vessels under the sclera that nourish the retina.
Uveitis (you-vee-I-tis) is an infection or inflammation of the uvea, the pigmented middle layer of the eye that contains the
iris, the ciliary body and the
choroid, which is composed of blood vessels that supply the retina. It is most common in people between ages 20 and 50.
There are four main categories of uveitis, characterized by the portion of the uvea that is affected:
- Anterior uveitis is the most common type and affects the iris, the front portion of the uvea. This is also called "iritis."
- Intermediate uveitis affects middle portion containing the ciliary body, vitreous and retina. This form is also known as "cyclitis."
- Posterior uveitis affects the choroid and optic nerve in the back portion and is also known as "choroiditis."
- Diffuse uveitis refers to inflammation of all portions of the uvea.
The are some 100 known causes of uveitis -- so many that in at least half the cases (and by some estimates, as many as 90 percent), the exact cause is never known. Most commonly, though, it results from trauma to the eye, such as an accident, or from a bacteria or viral infection that has spread from other parts of the body. Uveitis may also develop from autoimmune diseases such as juvenile rheumatoid arthritis or sarcoidosis, or from AIDS or other sexually transmitted diseases such as herpes or syphilis. Some forms are caused by genetics.
Blurred vision and pain are the most obvious signs of uveitis, but each category has its own symptoms:
- Anterior uveitis is often marked by redness around the iris, and an aching or intense pain. Along with blurred vision, there may also be tearing, light sensitivity and the pupil may appear smaller than usual.
- Intermediate uveitis is often characterized by the sudden presence of
floaters; however, occasional floaters are extremely common and do not necessarily indicate uveitis, any unusual incidence warrants an examination by an eye doctor. There may or may not be pain, and can affect both eyes.
- Posterior uveitis typically involves only pain and blurred vision.
- Diffuse uveitis may have any combination of symptoms.
Shielding eyes from trauma with
protective eyewear and quickly controlling infections such sexually transmitted diseases can prevent some cases. But most cases cannot be prevented.
Uveitis usually does not pose a serious threat to vision, but it can and needs to be evaluated by your eyecare provider. When identified and treated early, the prognosis for recovery is good. Topical eye drops and oral medications are typically used for treatment, but since intraocular pressure may increase, additional medications to lower IOP may be necessary.
Uveitis is diagnosed with a thorough examination of the eye with a
slit lamp microscope, which has an attached light that allows the doctor to examine your eye under high magnification, and with an ophthalmoscope to examine the retina and vitreous. In some cases, your doctor may recommend blood tests to determine the presence of infection.