Endoscopic assisted probing for symptomatic congenital nasolacrimal duct obstruction after one year of age.

Objective: When probing treatment for congenital nasolacrimal duct obstruction fails, it is often unclear whether it is due to technical difficulties or the severity of obstruction. Therefore our aim was to study the causes of probing failure and how to treat them.

Methods: In a prospective study, 36 lacrimal systems of 26 children aged 12 months to 4 years with congenital nasolacrimal duct obstruction (CNLDO) were treated by probing. In all children probing was done under direct vision using nasal endoscopy. Different forms of CNLDO were treated and studied to determine the potential predictors for treatment failure.

Results: The overall success rate was 94.5 %. Expected failure was attributed mainly to the construction of different forms of membranous penetration on probing. Surgical membranotomy at the area of Hasner's valve under direct nasal endoscopic visualization is an essential step for proper management of CNLDO.

Conclusions: Nasolacrimal duct probing under direct nasal endoscopic visualization can be considered as the standard treatment of CNLDO as it minimizes intranasal trauma and leads to a better surgical outcome.