AIM: To analyze the anatomical characteristics of nasolacrimal duct development in children with congenital nasolacrimal duct obstruction by nasolacrimal duct CT scan combined with three-dimensional reconstruction technology.

METHODS: Prospective case control study. Totally 84 children(84 eyes)with unilateral congenital nasolacrimal duct obstruction were treated in the Department of Ophthalmology of Baoding Children's Hospital from September 2018 to September 2020. The nasolacrimal duct CT scan combined with three-dimensional reconstruction was performed. The transverse diameter and anterior posterior diameter of bilateral nasolacrimal duct were measured, and the anatomical characteristics of nasolacrimal duct development were observed and analyzed. Paired t-test was performed on the transverse diameter and anteroposterior diameter of bilateral nasolacrimal duct.

RESULTS: Nasolacrimal duct CT scan combined with three-dimensional reconstruction can clearly show the anatomical characteristics of nasolacrimal duct development in children with congenital nasolacrimal duct obstruction. The transverse diameter of bony nasolacrimal duct was 4.63±0.92mm, anterior posterior diameter was 6.03±1.08mm, the transverse diameter of middle bony nasolacrimal duct was 4.02±0.88mm, anterior posterior diameter was 5.42±1.10mm, the transverse diameter of final bony nasolacrimal duct was 4.26±0.93mm, anterior posterior diameter was 5.66±1.02mm. The transverse diameter of the bony nasolacrimal duct in the initial segment of the contralateral side was 4.12±0.78mm, the anteroposterior diameter was 5.60±1.02mm, the transverse diameter of the bony nasolacrimal duct in the middle segment was 3.92±0.86mm, the anteroposterior diameter was 5.24±1.04mm, the transverse diameter of the bony nasolacrimal duct in the final segment was 4.30±0.98mm, the anteroposterior diameter was 5.52±1.04mm. The transverse diameter and anteroposterior diameter of the affected side were larger than those of the healthy side and enlarged(P<0.01). There was no significant difference between the affected side and the healthy side(P>0.05).

CONCLUSION:The development of bony nasolacrimal duct in the affected side of congenital nasolacrimal duct obstruction is different from that in the healthy side. The initial segment of the affected side expanded obviously.