Aims: To find the cure rate of late (second year of age) and very late (3-5 years of age) initial probing for congenital nasolacrimal duct obstruction (CNLDO) and to identify the factors contributing to the failure rate of the probing in older children.
Methods: In a prospective interventional case series study, 169 eyes of 125 consecutive patients (1-5 years old) with CNLDO underwent probing under general anaesthesia. Cure was defined as absence of tearing and discharge in the affected eye.
Results: 138 eyes of 101 patients aged 13-60 months (mean 23.4 (SD 10.2)) were included. Of 15 eyes (10.8%) with complex CNLDO, 80% presented after 24 months of age (p<0.0001). The cure rate was 89% in patients 13-24 months of age and 72% after the age of 24 months (p = 0.01). It was 90.2% in the membranous and 33.3% in the complex CNLDO in both late and very late probing (p<0.0001). There was a high correlation (r = 0.97) and no significant difference between the cure rate at 1 week and final follow up.
Conclusion: Accumulation of the complex CNLDO is the main risk factor for failure of probing in the older children. The outcome of the nasolacrimal duct probing at 1 week follow up is highly indicative of the final outcome.