To compare the nasolacrimal and nasal anatomical parameters in cases of acquired primary nasolacrimal duct obstruction and acute dacryocystitis.

The study included 62 eyes of 31 patients. The eyes were divided into three groups: Group A, comprising eyes presenting with acute dacryocystitis; Group B, comprising eyes with nasolacrimal duct obstruction but no previous episodes of dacryocystitis; and Group C, comprising eyes with an patent nasolacrimal duct. The coronal, axial, and sagittal computed tomography images of the cases were examined to assess parameters such as the canal’s entry and exit, the narrowest transverse and anteroposterior diameters, the anatomical type of the canal, inferior turbinate thickness, the angle between the inferior turbinate and the medial maxillary wall, and the direction of septal deviation.

No significant difference was found in any parameter when comparing eyes with acquired primary nasolacrimal duct obstruction to the contralateral eyes without obstruction (p > 0.05). Among the three groups, eyes with acute dacryocystitis (Group A) had significantly wider exit transverse and narrowest anteroposterior diameters compared to the other two groups (p = 0.000, p = 0.001, and p = 0.006, p = 0.042), with the narrowest transverse diameter also being significantly wider compared to Group B (p = 0.007). The angle of the inferior turbinate was significantly lower in Group A compared to Group B (p = 0.038). There was no significant difference between the groups regarding the anatomical type of the canal (p = 0.981).

While anatomical parameters do not show significant differences between eyes with primary acquired nasolacrimal duct obstruction and those without obstruction in the same individual, the wider canal diameters in eyes with acute dacryocystitis suggest that secondary changes associated with dacryocystitis or a predisposition to dacryocystitis might be present in eyes with nasolacrimal duct obstruction.