What causes nasolacrimal duct obstruction in children?
The most common cause is the failure of a membrane at the end of the tear duct (valve of Hasner) to open normally at or near the time of birth. Other causes of blocked tear ducts in children include: • Absent punctum (upper and/or lower eyelid) • Narrow or stenotic system • Infection • Nasal bone that obstructs the tear duct entering the nose.
