A common cause of tearing in children is neonatal dacryocystitis due to congenital nasolacrimal duct obstruction. The nasolacrimal duct is part of the tear drainage duct and is the latest of the tear drainage ducts to form. Often, the lower end of the nasolacrimal duct is still partially (Hasner flap) or completely covered by a mucosal fold at birth, and the “ductalization” is usually completed within a few months after birth.
Once the nasolacrimal duct is open, the child will not have tears in his eyes. The pattern of the nasolacrimal duct and Hasner’s flap is as follows: The clinical manifestation of nasolacrimal duct obstruction is the frequent storage of tears in the eyes, and neonatal dacryocystitis occurs when there is a discharge, often purulent, from the inner corner of the eye when squeezed. Since most children’s nasolacrimal ducts slowly complete “ductalization”, so, when it is simply manifested as watery eyes, no medication is needed, and local massage can be used to promote the opening of the lower end of the nasolacrimal duct (technique: from the lower lid orbital line between the inner side and the eye downward pressure, see the figure below); if accompanied by secretions, then local eye drops (e.g., Tolstoy If discharge is present, topical eye drops (e.g., Tobias eye drops, 3 to 4 times daily) are required. Most children heal spontaneously as the nasolacrimal duct opening develops on its own, or with local massage and pressure. If conservative treatment does not work, lacrimal duct exploration can be considered after the age of half a year.