To evaluate the clinical efficacy of lacrimal endoscopy in patients with nasolacrimal duct obstruction (NLDO) and to compare the dacryocystography (DCG) and lacrimal endoscopic findings between patients with epiphora.

We conducted a retrospective chart review of 31 eyes of 23 patients who underwent an irrigation test, DCG, and lacrimal endoscopy from December 2014 to February 2016. We compared the clinical characteristics, and dacryocystographic findings, and lacrimal endoscopic findings of the patients, and analyzed whether or not these findings agree.

Thirty-one eyes showed complete obstruction (13 eyes, 41.9%), partial obstruction (7 eyes, 22.6%), or patency (11 eyes, 35.5%) on irrigation test. Thirteen eyes with complete obstruction on irrigation test presented with complete obstruction (11 eyes, 84.6%) or secondary dilation (2 eyes, 15.4%) of the lacrimal sac at DCG. In terms of the level of obstruction, there was no difference between the two examinations. However, twelve eyes with complete obstruction at DCG; showed narrowing (4 eyes, 33%), granulation tissue (3 eye, 25%), mucus occlusion (2 eyes, 17%), stones (1 eye, 8%), or mucosal edema (2 eyes, 17%) on lacrimal endoscopy. Nineteen eyes with partial obstruction at DCG showed narrowing (6 eyes, 32%), mucus (5 eye, 26%), granulation tissue (4 eyes, 21%), or stones (4 eyes, 21%) on lacrimal endoscopy.

Lacrimal endoscopy allowed real-time observation inside the lacrimal passage that cannot be detected using DCG. Both methods provide comprehensive investigations of the nasolacrimal passage system, and these methods are complementary to understand the pathophysiology of nasolacrimal duct obstruction as well as planning treatment. Lacrimal endoscopy is very useful in investigating the lacrimal drainage passage in patients with NLDO, and this method is comparable to DCG.