RESUMEN
Congenital nasolacrimal duct obstruction is a major cause of epiphora in infants and the incidence is known to be 1.75% to 12.5%. Debates continues about optimal management for patient`s age. Both early intervention and late intervention have advantages and disadvantages. This study was designed to evaluate the effect of probing for congenital nasolacrimal duet obstruction in association with the patient` s age to decide the optimal timing for probing. From January 1993 to November 1996, 85 eyes of 68 patients were diagnosed as congenital nasolacrimal duct obstruction and had probing under topical anesthesia. The success of probing was defined as improvement of symptoms for at least 4 weeks of period after probing. The probing was successful in 73 out of 85 eyes and the success rate was 85.8%. The success rate of infants between 3 to 9 months of age was 92.6%. The success rate of infants older than 10 months of age was 74.2%. The difference between two groups was statistically significant(P<0.05). The success rate of probing for congenital nasolacrimal duct obstruction was highly associated with the age and it began to decrease when the age of the patient was over 10 months. Therefore it is recommendable to probe for congenital nasolacrimal duct obstruction before the age of the patient reaches 10 months.