A blocked tear duct in an infant can cause excessive tearing and mucus build-up on the eyelids and eye lashes. This occurs when a thin tissue in the nose does not open before birth, blocking the drainage of tears from the eyes into the back of the nose and throat. Many cases resolve within 6-12 months after birth. Blocked tear ducts can be treated with a brief surgical procedure in which a thin, blunt metal probe is passed through the tear drainage system to open the obstruction. Infants and children experience no pain after the procedure, but blood-tinged tears or nasal secretions are common.