Measuring nasolacrimal duct volume using computed tomography images in nasolacrimal duct obstruction patients in Korean

● AIM: To investigate nasolacrimal duct (NLD) volume in Korean patients and to examine the correlation between NLD volume and obstruction. ● METHODS: Of patients who underwent orbital computed tomography from March 2013 to January 2016, patients diagnosed with NLD obstruction were classified into the patient group and patients without obstruction were classified into the control group. The NLD volume was measured using the Image J program, which showed the NLD in axial, coronal, and sagittal images on computed tomography. ● RESULTS: The average value of men’s NLD volume, 265.33±90.57 mm³, was significantly larger than women’s, 211.87±68.61 mm³ (P=0.009). In the patient group, the NLD volume of the obstructed eyes, 242.49±82.93 mm³, and the non-obstructed eyes, 225.20±73.20 mm³, were significantly higher than the control group, 217.61±82.04 mm³ (P<0.001, P<0.001). ● CONCLUSION: The NLD volume is larger in men than in women in Korean adults. If there is NLD obstruction in women, the NLD volume is larger and it is judged that inflammatory reaction caused a chronic change in the bone around the NLD and affect the measurement of NLD volume.