The uvea is a part of the eye, made up of the iris, ciliary body and choroid.
Uveitis is when any part of the uvea is inflamed. Uveitis can cause visual loss by a variety of ways, including swelling of the nerves in the retina. Patients with uveitis also frequently get cataract and glaucoma as a result.
A doctor can see inflammation in the eye using a microscope, (there are abnormal floating cells).
Iritis, when specifically the iris is inflamed, is the most common type of uveitis.
Patients with iritis have redness, and are often bothered by light.