Inflammation or infection of the outer membrane of the eyeball and the inner eyelid. Pink eye, also called conjunctivitis, is a infection of the eye's conjunctiva usually caused by a bacteria or virus that results in red, itchy, painful. Pink eye (conjunctivitis) is an inflammation or infection of the transparent membrane (conjunctiva) that lines your eyelid and covers the white part of your eyeball. Conjunctivitis is often called pink eye. Pink eye is a general term for the symptoms of an infection or allergies. People often call conjunctivitis “pink eye” because it can cause the white of the eye to take on a pink or red color.