Diagnoses in Ocular Immunology & Uveitis
Immunology and Ophthalmology - How They Overlap
Immunology is the branch of medicine that is concerned with the body's natural systems that regulate control of disease processes. The body's immune system, which generally protects us from germs and cancer cells, can become deranged and deregulated, which results in an immune attack on part of one's own body. This state is termed autoimmunity, or an immune attack against oneself.
Autoimmune diseases result from the existence of autoimmunity. The best known autoimmune disease is rheumatoid arthritis (RA). In RA, the white blood cells of the immune system become deregulated or "confused" and begin to attack the individual's joints.
A number of autoimmune diseases can occur when the eye, or various parts of the eye, is attacked by white blood cells. Often, the autoimmune disease is systemic, i.e., a variety of organs throughout the body system are being attacked. Examples of such diseases include rheumatoid arthritis, systemic lupus erythematosus, polyarteritis nodosa, scleroderma, relapsing polychondritis, and inflammatory bowel disease (ulcerative colitis and Crohn's disease).
All of these diseases can affect the eye, causing corneal ulcers, sclerosis, uveitis, or other inflammation.
Technically, uveitis is the term for a range of inflammatory diseases that affect the uvea, which is the collection of pigmented structures in the middle of the eye including the iris, ciliary body and choroid. Because uveal tissues contain many blood vessels, they are susceptible to inflammation from a variety of eye disorders. The definition of uveitis has been broadened to include inflammation of any internal eye structure, including the retina. If the inflammation involves only one or two structures of the eye, a more specific name is given (iritis, cyclitis, choroiditis, iridocyclitis, chorioretinitis, episcleritis). Inflammation of the entire eye is called panuveitis.
If the cause of uveitis is an infection, it is possible that you may "catch" that infectious agent from somebody, some thing, or some animal, including your household pets. Infectious agents that cause ocular inflammation in the eye include viruses, fungi, parasites, bacteria and other infectious agents.
If the uveitis occurs on the basis of autoimmunity (the most common form of uveitis), then the uveitis is the sign that your own immune system is inappropriately "attacking" part of your own body. In such cases, you do not "catch" it from anything, but it develops from other systemic disease processes including sarcoidosis, some arthritis syndromes and chronic intestinal diseases. It can also result from trauma to the eye.
Altogether, approximately 60 different entities, infectious and non-infectious, can cause uveitis. Uveitis occurs most commonly during young adulthood and middle life, but it can occur at any age. The eye generally tolerates mild degrees of inflammation without serious consequences. Severe, prolonged intraocular inflammation, however, can lead to serious complications that cause impaired vision or even blindness.
Patients with uveitis or immune disease may not be aware of their illness or its effect on their eyes until it has progressed. Severe uveitis with sudden onset may cause any of the following: blurring of vision, redness, sensitivity to light, and aching in the affected eye or eyes. It is important to have regular eye examinations, and to monitor eye health closely in patients with immunologic disease.