Overview
One or both of your eyes may be red and itchy. You may have trouble seeing
clearly. And you likely have a gritty feeling or discharge in your eye. These
may be indications of conjunctivitis.
Conjunctivitis is an inflammation of the conjunctiva, the transparent
membrane that lines your eyelids and part of your eyeballs. In conjunctivitis,
inflammation causes small blood vessels in the conjunctiva to become more
prominent, resulting in a pinkish or reddish cast to your eyes. Pinkeye and red
eye are terms that many people commonly use to refer to all types of
conjunctivitis.
Viruses, bacteria, allergies, dry eyes, or irritation due to exposure to wind
or dust can cause conjunctivitis. Allergic conjunctivitis is a response to an
allergy-causing substance (such as pollen) rather than an infection. Both viral
and bacterial conjunctivitis are very contagious. Although common among
children, they also affect adults. The most virulent and contagious type of
conjunctivitis — the one responsible for outbreaks in the schools — is
called epidemic keratoconjunctivitis.
Inflammation makes conjunctivitis an irritating condition, but it is usually
harmless to vision. However, because it can be highly contagious, it must be
diagnosed and treated early. Occasionally, conjunctivitis can cause eye
complications.
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