eye disorders
Uveitis
Introduction
Uveitis is inflammation anywhere in the pigmented inside lining of the eye, known as the uvea or uveal tract. The uveal tract may become inflamed because of infection, injury, a bodywide autoimmune disorder (which causes the body to attack its own tissues), or for unknown reasons. Symptoms may include eye ache, eye redness, floaters, loss of vision, or a combination. Treatment typically includes corticosteroids (as eye drops, taken by mouth, or injected into or around the eye), drops that dilate and relax the pupil in the affected eye, and sometimes drugs that suppress the immune system. Theuveal tractconsists of three structures: The iris The ciliary body The choroid Theiris,the colored ring around the black pupil, opens and closes to let more or less light into the eye, just like the shutter in a camera. Theciliary bodyis the set of muscles that, by contracting, allows the lens to become thicker so the eye can focus on nearby objects. By relaxing, the ciliary body allows the lens to become thinner so the eye can focus on distant objects. This process is called accommodation. Thechoroid,which lines part of the back part of the eyeball, extends from the edge of the ciliary muscles to the optic nerve at the back of the eye. The choroid lies between the retina on the inside and the sclera on the outside. The choroid contains both pigmented cells and blood vessels that nourish the inside parts of the eye, particularly the retina. The uveal tract consists of three structures: the iris, ciliary body, and choroid. Part or all of the uveal tract may become inflamed. Inflammation limited to part of the uveal tract is named according to its location: Anterior uveitisis inflammation in the front of the uveal tract, including the iris. Intermediate uveitisis inflammation in the middle of the uveal tract, and typically also involves the jellylike substance that fills the eyeball (called the vitreous humor). Posterior uveitisis inflammation in the back of the uveal tract and can involve the retina and choroid. Panuveitisis inflammation that affects the entire uveal tract. Sometimes uveitis is referred to by the name of the specific part that is inflamed. For example,iritisis inflammation of the iris,choroiditisis inflammation of the choroid, andchorioretinitisis inflammation that involves both the choroid and the overlying retina. Inflammation of the uveal tract is limited to one eye in many people with uveitis but may involve both eyes. 