The tear duct is a channel/passage which runs from a tiny opening in the medial lids through the bone to the inside of the nose, and drains the tears and mucus the eye produces. It should open just before or just after birth but sometimes remains blocked for a considerable time after that, causing watering and discharge from the eye. It is harmless, and does not affect the health of the eye or the vision, although it can make the eyelids red and sore and slightly increases the frequency of infective conjunctivitis.