The conjunctiva is exposed to bacteria and other irritants. Tears help protect the conjunctiva by diluting bacteria and washing it away. Tears also contain enzymes and antibodies which kill bacteria.
There are many causes of conjunctivitis. Viruses are the most common cause. Other types include bacterial, Chlamydial, fungal, and parasitic agents (rarely).
Pink eye refers to a viral infection of the conjunctiva. These infections are very contagious, especially among children. The virus is similar to the type which cause the common cold. The key is handwashing to prevent spreading the virus.
Bacteria are an uncommon cause of conjunctivitis. Many physicians will give a mild antibiotic eyedrop for all cases of pink eye to prevent bacterial conjunctivitis. Other causes are allergies (allergic conjunctivitis), chemical exposure, and certain systemic diseases.
Newborns can be infected by bacteria in the birth canal. This condition is called ophthalmia neonatorum, and it must be treated immediately to preserve sight. Use of contact lenses, particularly extended-wear lenses, can cause conjunctivitis.
See also:
|