ObjectiveTo evaluate the effectiveness of dacryoendoscopic-assisted laser dacryoplasty with silicone intubation (DLDI) for the management of nasolacrimal duct obstruction (NLDO) or stenosis, and to identify the factors associated with DLDI failure.Methods and analysisThis study was designed as a prospective, single-centre cohort study. Patients with NLDO or stenosis who underwent DLDI from December 2019 to December 2021 at Tianjin Eye Hospital were considered for enrolment. The Kaplan-Meier estimator was used to assess the anatomical and functional success rate of DLDI within 2 years follow-up after removal of the silicone stent. Cox proportional hazards regression models were used to identify risk factors for treatment failure.Results170, 174 and 178 eyes were included in Groups A (proximal NLDO), B (distal NLDO) and C (nasolacrimal duct stenosis), respectively. The overall anatomical success rate was 84.8% for the entire cohort at the 2-year follow-up. The cumulative anatomical or functional success rate for Groups B and C was significantly higher than that for Group A. In the multivariable model, a higher risk of failed DLDI surgery was associated with a history of chronic dacryocystitis (HR=3.07; p<0.001) and a longer duration of epiphora than 1 year (HR=2.67; p<0.001). Of the 522 eyes, 37 patients (7.1%) had surgery-related complications.ConclusionsDLDI is an effective minimally invasive technique for treatment in patients with distal NLDO or stenosis. Factors associated with a higher risk of reoperation include a longer duration of epiphora and a history of chronic dacryocystitis.Trial registration numberNCT05999058.