Uveitis is a general term that refers to inflammation or swelling of the eye's structures responsible for its blood supply. These structures are collectively known as the uveal tract, and include the iris, ciliary body, and choroid.
Uveitis is classified by the structures it affects, the underlying cause, and whether it is chronic (lasting more than 6 weeks), or acute in nature. There are four main categories of uveitis.
Dacryocystitis is an infection of the tear sac that lies between the inner corner of the eyelids and the nose. It usually results from blockage of the duct that carries tears from the tear sac to the nose. The blocked duct harbors bacteria and becomes infected.
Subconjunctival hemorrhage occurs when a small blood vessel under the conjunctiva breaks and bleeds. It may occur spontaneously or from coughing, heavy lifting, or vomiting. In some cases, it may develop following eye surgery or trauma. Subconjunctival hemorrhage tends to be more common among those with diabetes and hypertension.
Pterygium is a raised, wedge-shaped growth of the conjunctiva. It is most common among those who live in tropical climates or spend a lot of time in the sun. Symptoms may include irritation, redness, and tearing. Pterygiums are nourished by tiny capillaries that supply blood to the tissue. For some, the growth remains dormant, however, in other cases it grows over the central cornea and affects the vision.