To evaluate the morphometric differences of bony nasolacrimal ducts (BNLDs) using computed tomography (CT) in Koreans with primary acquired nasolacrimal duct obstruction (PANDO).

From March 2014 to March 2016, 40 unilateral PANDO patients and 40 control subjects were retrospectively reviewed. The axial, sagittal, and coronal planes of CT were used for image evaluation. The proximal, minimal, and distal transverse diameters (TDs) of the BNLD were assessed. The length, sagittal orientation angle of BNLD, relative lacrimal sac-BNLD angle, nasal floor-BNLD angle, and turbinate angle were investigated. In addition, the distance between the bilateral BNLD and inter-frontozygomatic suture distance were also measured.

There were no morphologic differences between the PANDO and non-PANDO sides within PANDO patients. The proximal and minimum BNLD TD measurements were significantly narrower in the PANDO patients, as compared with the control group ( p = 0.010 and p = 0.017, respectively). The lacrimal sac-BNLD angle, nasal floor-BNLD angle, and turbinate angle also exhibited statistically significant differences between the PANDO patients and the control group ( p = 0.019, p = 0.001, and p < 0.001, respectively).

Although this study was performed in a small group, the narrow proximal and minimum BNLD TD in PANDO patients (in both the PANDO and non-PANDO sides) may be associated with PANDO development in Koreans. Additionally, the narrow lacrimal sac-BNLD, nasal floor-BNLD, and turbinate angle might be possible causative factors of PANDO.