Pinkeye (conjunctivitis) is redness and swelling of the conjunctiva,
the mucous membrane that lines the eyelid and eye surface. Pinkeye symptoms
usually start in one eye and may then spread to the other eye. The most common
type of pinkeye is caused by a virus and occurs most often in adults.
Viral pinkeye is often caused by an adenovirus, which is a common
respiratory virus that can also cause a sore throat or upper respiratory
infection. The herpes virus can also cause viral pinkeye.