Close-up photograph of the eye, showing conjunctivitis, an inflammation of the conjunctiva, the delicate mucous membrane covering the front of the eye & the insides of the eyelids. The conjunctiva becomes red, swollen & may discharge water or pus. Conjunctivitis is caused by bacterial infection, allergy, or by physical or chemical irritants. Bacterial infections respond to antibiotic eye drops. Uncomplicated conjunctivitis is generally not serious & does not usually affect vision.