Uveitis is a general medical term for inflammation affecting the middle layer of the eye which is called the uvea. The uvea consists of 3 distinct structures: iris, ciliary body, and the choroid. The iris is the colored ring around the pupil of the eye; the choroid is a thin layer of blood vessels covering both the back and sides of the eye; and the ciliary body is a ring shaped structure between the iris and choroid that joins the iris with the retina, the inner layer of the eye. The ciliary body has two main functions: its muscles serve to focus the lens, and it also produces the aqueous humor, a nourishing liquid that bathes the front of the eye. Uveitis may affect any or all of these 3 parts of the eye.
The primary symptom of uveitis affecting the choroid, known as posterior uveitis, is a vague feeling of hazy or fading vision. Some people see black spots that seem to float before their eyes. Iritis, also known as anterior uveitis, is a type of uveitis that affects the iris, although the term is sometimes used for inflammation that includes the ciliary body as well. Iritis can cause redness, pain, blurred vision, an intolerance to light, and, sometimes, headaches.
Uveitis is often linked to an autoimmune disorder such as rheumatoid arthritis and other conditions which may have an autoimmune cause, but it can also be the result of infection. More often than not, there is no obvious cause. Uveitis can be a precursor of other eye problems, including glaucoma and detached retina. If you suspect you may have uveitis, then you should consult an ophthalmologist for a complete eye examination.