[Spontaneous resolving rate of congenital nasolacrimal duct obstruction and success rate of late probing after age 18 months: historical cohort study].

PURPOSE: To determine the spontaneous resolving rate of congenital nasolacrimal duct obstruction (CNDO) and the success rate of late probing after age 18 months. PATIENTS AND METHODS: A single-center, historical cohort study. We retrospectively reviewed the medical records of infants less than 18 months of age who were diagnosed with CNDO and referred to the Department of Ocular Plastic & Orbital Surgery of the Seirei Hamamatsu General Hospital in Japan. We conservatively observed them up to the age of 18 months. We performed late probing for CNDO in the patients 18 months of age or older using lacrimal endoscopy. RESULTS: Eighty-two obstructed nasolacrimal ducts of 72 patients with a mean age of 8.6 +/- 5.4 months were included. Twenty-five lacrimal ducts (31%) had a history of early probing in other hospitals. The spontaneous resolving rate was 42 (51%) at 12 months, and 64 (78%) at 18 months of age. There was no significant difference in spontaneous resolving rate between the existence and absence of early probing. Nine lacrimal ducts (11%) were treated with late probing with silicone tube intubation after age 18 months, and all were cured. CONCLUSIONS: The spontaneous resolving rate of CNDO either with or without early probing history was about 80% at 18 months of age with conservative medical management. Late probing with tube intubation after age 18 months had a high success rate.