Conjunctivitis - Overview
Inflammation - conjunctiva; Pink eye
Definition of Conjunctivitis:
Conjunctivitis is swelling (inflammation) or infection of the membrane lining the eyelids (conjunctiva).
Click here to see a video about conjunctivitis.
Causes, incidence, and risk factors:
The conjunctiva is exposed to bacteria and other irritants. Tears help protect the conjunctiva by washing away bacteria. Tears also contain enzymes and antibodies that kill bacteria.
There are many causes of conjunctivitis. Viruses are the most common cause. Other causes include:
- Allergies (allergic conjunctivitis)
- Certain diseases
- Chemical exposure
- Parasites (rarely)
- Use of contact lenses (especially extended-wear lenses)
"Pink eye" refers to a viral infection of the conjunctiva. These infections are especially contagious among children.
Newborns can be infected by bacteria in the birth canal. This condition is called ophthalmia neonatorum, and it must be treated immediately to preserve eyesight.
- Reviewed last on: 8/3/2010
- Linda J. Vorvick, MD, Medical Director, MEDEX Northwest Division of Physician Assistant Studies, University of Washington, School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.
Wright JL, Wightman JM. Red and painful eye. In: Marx JA, ed. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 7th ed. Philadelphia, Pa: Mosby Elsevier; 2009:chap 32.
Rubenstein JB, Virasch V. Conjunctivitis: Infectious and noninfectious. In: Yanoff M, Duker JS, eds. Ophthalmology. 3rd ed. St. Louis, Mo: Mosby Elsevier; 2008:chap 4.6.
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