AIM: To measure the transverse diameter of nasolacrimal duct in patients with nasolacrimal duct obstruction, and to analyze the difference of the transverse diameter of the upper, middle and lower nasal nasolacrimal ducts between the diseased eyes and the normal eyes, between the male and the female eyes, and of different ages and sexes and then explore the correlation between the diameter of nasolacrimal duct and nasolacrimal duct obstruction based on computed tomography(CT)dacryocystography.

METHODS: From April 2014 to January 2017 in Chengdu University of Traditional Chinese Medicine Affiliated Hospital of ophthalmology in tears or pus for complaints, diagnosis of nasolacrimal duct obstruction in 152 patients(179 sick eyes, 125 normal eyes). Among them 25 cases were male(sick eyes 28 eyes, normal eye 22 eyes), 127 cases were female(sick eyes 151 eyes, normal eyes 103 eyes), age from 4 to 87 years old, mean age 53.44±16.06 years old. All patients with perfusion of 30% iohexol injection in lacrimal passages, and immediately examined with CT scan, upload CT images on PACS workstation for 3D reconstruction of nasolacrimal duct, oblique coronal of nasolacrimal duct and its adjacent structure were observed. We measured and analyzed the transverse diameters of the upper, middle and lower nasal nasolacrimal ducts between men and women, diseased eyes and non diseased eyes, and between the diseased eyes of different age groups.

RESULTS: The transverse diameter of the upper, middle and lower nasal nasolacrimal duct was no significant difference between the diseased eye and the normal eye, between the male and female diseased eyes, and between the diseased eyes of different age groups(P>0.05). The transverse diameters of the upper, middle and lower nasolacrimal ducts were significantly different between the diseased eyes and the normal eyes(P<0.001), and the transverse diameter of the middle mouth was the smallest.

CONCLUSION: Transverse diameter of bony nasolacrimal duct is not a risk factor for nasolacrimal duct obstruction.