Uveitis (pronounced you-vee-EYE-tis) is basically an internal inflammation of the eye. The condition involves the middle layers of the eye, also called the uveal tract or uvea. The uvea includes the iris (colored part of the eye), choroid (a thin membrane containing many blood vessels), and the ciliary body (the part of the eye that joins these together).
The uvea is very important because its many veins and arteries transport blood to the parts of the eye that are critical for vision.
Most of the focusing power in the eye occurs along the front surface, called the cornea, which is the clear "window" in the front of the eyeball. The next structure involved in focussing is the lens, which sits behind the cornea inside the eye. The ideal cornea has a symmetrically curved surface, like a basketball. Astigmatism is caused by a cornea or a lens that is not symmetrical. As a result, people with significant astigmatism may have distorted or blurry vision.
Astigmatism is measured in...
Uveitis may develop rapidly, and it is very important that you see your eye doctor for a complete eye exam if you develop these symptoms, especially if a painful, red eye does not clear up quickly.
Left untreated, uveitis may permanently damage your vision.
What Causes Uveitis?
Uveitis has many potential causes, including infection with a virus. Other potential causes include fungus, bacteria, parasite, inflammatory disease affecting other parts of the body, or injury to the eye.
There are four types of uveitis:
Iritis is the most common form of uveitis. It affects the iris and is often associated with autoimmune disorders such as rheumatoid arthritis or sarcoidosis. Iritis may develop suddenly and may last weeks, even with treatment. Rare cases are chronic and require close, long- term monitoring.
Cyclitis is an inflammation of the middle portion of the eye and may affect the muscle that focuses the lens. This also may develop suddenly and last several months.
Retinitis affects the back of the eye. It may be rapidly progressive, making it difficult to treat. Retinitis may be caused by viruses such as shingles or herpes and bacterial infections such as syphilis or toxoplasmosis.
Choroiditis is an inflammation of the layer beneath the retina. It may also be caused by an infection such as tuberculosis.
Retinitis and choroiditis can each be caused by an autoimmune disease such as rheumatoid arthritis or lupus. In a large number of cases, the cause of uveitis is not known. Stress is sometimes suspected since the inflammation is triggered by the body's immune system.