Conjunctivitis, also known as pink eye, is an inflammation of the transparent membrane that lines the eyelid and covers the white part of the eye. The most common cause is viral infection. Symptoms may range from mild to severe and include eye redness, swelling of the eyelids, increased tearing, irritation, sensitivity to light, and discharge. It is diagnosed based on symptoms, and while most viral cases will clear up on their own in 1 week, bacterial infections are usually treated with antibiotic eye drops or ointment. Conjunctivitis is highly contagious and can spread through direct contact, so proper hand washing and avoiding sharing towels/tissues is important to prevent spread.