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Conjunctivitis

The white of the eye and the inner surfaces of the lids are covered by a transparent membrane called the conjunctiva. Conjunctivitis is inflammation of the conjunctiva.

There are two main types of conjunctivitis – allergic and infective. Allergic conjunctivitis happens when the immune system of the body attacks something that is not really harmful, such as pollen or make-up, and causes inflammation. Infective conjunctivitis is caused by viruses or bacteria infecting the eye. The immune system fights it, causing swelling. Infection is the most common cause of conjunctivitis.

Conjunctivitis is sometimes called pink eye because the blood vessels in the eye are irritated and get enlarged, making the eye look red or pink.