A Systematic Review and Meta-Analysis of the Success Rate of the Primary Probing in Pediatric Patients with Congenital Nasolacrimal Duct Obstruction in Different Age Groups.

Primary probing of the nasolacrimal duct remains the first-line surgical intervention for congenital nasolacrimal duct obstruction (CNLDO) in infants and young children. However, age-dependent success rates have been less thoroughly investigated. This systematic review and meta-analysis aims to evaluate the age-related success rates of primary probing in children with CNLDO. Systematic literature searches were performed in PubMed, Web of Science, Scopus, ScienceDirect, and Google Scholar in May 2025. A random-effects model was applied to estimate the overall success rate, while sensitivity analyses and publication bias assessments were performed to explore sources of variability. All statistical analyses were carried out using the "meta" and "metafor" packages in RStudio. This meta-analysis reveals age-stratified success rates of primary probing for CNLDO: the highest pooled success rate occurred in infants aged 0-6 months (90.67%, I = 81%, < 0.01), with procedures under general anesthesia achieving 95.42% (I = 50%; = 0.11) efficacy. Success rates remained favorable in the 6-12 month group (85.18%, I = 86%, < 0.01 overall; 89.60% with general anesthesia) but declined progressively thereafter (82.34%, I = 78%, < 0.01 at 12-24 months). While a modest rebound occurred in the 24-48 month group (85.33%, I = 69%, < 0.01), the oldest cohort (48+ months) demonstrated markedly reduced efficacy (63.47%, I = 66%, = 0.05), despite exclusive use of general anesthesia. Primary probing yields the most favorable outcomes when conducted before 12 months of age, particularly under general anesthesia. Nonetheless, the overall certainty of evidence is low-mainly due to variability across studies-which should be taken into account in clinical decision-making.