Uveitis is the inflammation of the uvea, a part of the eye.

The eye is shaped much like a tennis ball, hollow inside with three different layers of tissue surrounding a central cavity. The outermost is the sclera (white coat of the eye) and the innermost is the retina (image-gathering tissue in the back of the eye much like the film in a camera).

The middle layer between the sclera and the retina is called the uvea, from the Greek word "uva" meaning grape. In the laboratory, it looks much like a...