Nasolacrimal duct probing in infants.

Use of a fiberoptic endoscope to visualize the vault of the inferior turbinate during lacrimal duct probing and irrigation revealed a high incidence of false passages. This was confirmed on dacryocystofluoroscopy. The creation of false passages as documented by us can help explain clinical probing failure in apparently successful probings in which "metal on metal" is felt in the nose.