Diversity in Lacrimal Pathway Morphology Among Japanese Patients with Congenital Nasolacrimal Duct Obstruction

Abstract Objective: This study aimed to explore the diversity in lacrimal pathway morphology among Japanese patients with congenital nasolacrimal duct obstruction (CNLDO) by examining dacryocystography (DCG) images. Study Design: Prospective observational study Methods: The study involved 64 patients who underwent DCG prior to undergoing general anesthesia surgery for unilateral CNLDO at our institution between July 2012 and February 2023. Several parameters were measured from the sagittal section DCG images: (1) The angle between the lacrimal sac and the nasolacrimal duct, (2) The angle between the superior orbital rim, the center of the lacrimal sac, and the nasolacrimal duct, (3) The length of the bony nasolacrimal duct, (4) The length of the lacrimal sac. Additionally, following parameters were measured from coronal section images: (5) The angle formed by the lacrimal sac and the nasolacrimal duct, (6) The angle formed by the lacrimal sac concerning the midline. Results: The average age of the patients was 34.3 months, ranging from 14 to 84 months. The mean ± standard deviation of the measurements of the above parameters were (1) –1.2 ± 16.5° (range, –44.6° to +46.6°), (2) –5.0 ± 10.3° (range, –24.0° to +19.0°), (3) 8.0 ± 2.5 mm (range, 3.1 mm to 14.8 mm), (4) 10.2 ± 2.4 mm (range, 6.5 mm to 16.0 mm), (5) 15.6 ± 11.2° (range, –16.8° to +41.0°), (5) 15.1 ± 5.2° (range, +3.3° to +29.8°). Our study revealed that all parameters, except for parameter (4) (length of the lacrimal sac), conformed to a normal distribution, as determined by the Shapiro-Wilk test. Conclusions: This study offers valuable anthropometric data derived from DCG images, and the results emphasize the substantial variability in lacrimal pathway morphology among individuals. Moreover, probing with straight probes was considered anatomically infeasible in 25.0% of cases in the patients included in this study. These findings have the potential to impact the diagnosis and treatment planning for CNLDO.