Abstract:AIM: To evaluate the clinical presentation, nasal endoscopic findings, and surgical outcomes of probing surgery (PS) or bicanalicular silicone tube intubation (BCI) performed under nasal endoscopic guidance (NEG) in pediatric patients with congenital nasolacrimal duct obstruction (CNLDO), regardless of previous surgical history. METHODS: This retrospective cross-sectional study included CNLDO patients with data on demographics, fluorescein dye disappearance test (FDDT) results, dacryoscintigraphy findings, prior surgeries, and outcomes of NEG-PS or NEG-BCI. NEG-BCI using Crawford stents was performed intraoperatively in complex cases. Intraoperative and postoperative complications were recorded. Surgical success was evaluated clinically and with FDDT at postoperative months 1 and 6. Stents were retained for a minimum of 12wk, with follow-up for at least 6mo after removal. RESULTS: Of the 67 pediatric patients (67 eyes, mean age 37.4±17.5mo), 44 (65.7%) were female. Preoperative FDDT was graded 3+ in 85.1% of cases, and dacryoscintigraphy confirmed obstruction in 92.5%. Nine patients (13.4%) had a history of PS. At 6mo, surgical success was achieved in 96.6% (28/29) of the NEG-PS group and 71.1% (27/38) of the NEG-BCI group (P=0.009). All cases with probe exit through the inferior meatus (IM) were successful, whereas exits through the inferior concha (IC) or submucosal IM (SM) were significantly associated with failure (P<0.001). CONCLUSION: NEG allows intraoperative classification of CNLDO and selection of surgical method based on real-time anatomical findings. Probe exit through the IM predicts a high likelihood of success, whereas IC or SM exits are risk factors for failure. Incorporating NEG into routine practice may improve surgical precision and reduce the need for repeated procedures.