Uveitis is the inflammation of the uvea, the pigmented layer that lies between the inner retina and the outer fibrous layer composed of the sclera and cornea. The uvea consists of the middle layer of pigmented vascular structures of the eye and includes the iris, ciliary body, and choroid. Uveitis is an ophthalmic emergency and requires a thorough examination by an ophthalmologist or optometrist and urgent treatment to control the inflammation. It is often associated with other ocular problems.
This type affects the front of the eye, normally the iris (iritis) or the ciliary body (iridocyclitis). Iritis, strictly speaking is an older term for Anterior Uveitis but is still used frequently. Iritis is by far the most common type of Uveitis and also the most readily treated. Iritis is something that needs close monitoring because complications such as raised eye pressure and cataracts can occur.
This type affects the area just behind the ciliary body (pars plana) and also the most forward edge of the retina (see the diagram above). This is the next most common type of Uveitis.
This type occurs when the inflammation affects the part of the Uvea at the back of the eye, the choroid. Often the retina is affected much more in this group.The choroid is basically a layer rich in small blood vessels which supplies blood to the retina
Uveitis may be an immune response to fight an infection inside the eye. While representing the minority of patients with uveitis, such possible infections include. brucellosis, herpesviruses, leptospirosis, Lyme disease etc.