AIM: To investigate the success rate and relevant factors for probing and irrigation in children with congenital nasolacrimal duct obstruction(CNDO).

METHODS: A total of 261 eyes from 235 children were treated surgically with probing due to CNDO between 2005 and 2011. Patients were classified into three groups with respect to age. Group 1(12-24 months), group 2(24-48 months)and group 3(48-120 months)consisted of 131, 82 and 48 eyes respectively. Probing was performed for upper and lower punctum under general anesthesia. Postoperative control visits were performed on 1^st day, 1^st and 2^nd weeks, 1^st and 3^rd months. Success rate and correlation with age were analyzed using Mann Whitney U and Chi-square tests.

RESULTS: The mean age for the 235 patients(122 females, 113 males)was 27.6±10.7(12-120)months. The rates of success after one probing in groups 1, 2 and 3 were 90.1%, 85.4% and 47.6% respectively and the procedure was significantly more successful in groups 1 and 2(P<0.05). Probing was repeated in 53(20.3%)patients and rates of success in groups 1, 2 and 3 were 61.5%, 58.3% and 25.0% respectively.

CONCLUSION: Probing is an effective treatment for CNDO especially in children < 2 years of age. Rate of success decreases with advancing age, but second probing and application both through upper and lower canaliculi are measures that may improve the outcome.