Analysis of lacrimal duct morphology from cone-beam CT dacryocystography in a Japanese population

Abstract Purpose: The morphology and inclination of the lacrimal duct differ among individuals and ethnic groups. We used cone-beam CT dacryocystography (CBCT-DCG) to measure several parameters of the lacrimal duct in a Japanese population.Methods: We retrospectively analyzed the CBCT-DCG images of 102 cases diagnosed with unilateral primary acquired nasolacrimal duct obstruction (PANDO) at Ehime University Hospital from December 2015 to May 2021. We investigated the following parameters of the lacrimal duct on the contralateral side of unilateral PANDO: 1) the angle formed by the superior orbital rim–internal common punctum–nasolacrimal duct opening, 2) the angle formed by the lacrimal sac and the nasolacrimal duct, 3) the length of the lacrimal sac, 4) the length of the nasolacrimal duct.Results: The measurements of the above parameters were as follows: 1) 10.2 ± 7.8° (range, −11° to +27°); 2) −6.3 ± 14.1° (range, −43° to +40°); 3) 8.9 ± 2.3 mm (range, 4.3–17.1); 4) 13.2 ± 2.7 mm (range, 5.7–20.7). Of these parameters, values of all except 3) followed a normal distribution.Conclusions:We reported anthropometric data analyzing the morphology of the lacrimal ducts using CBCT-DCG in a Japanese population.