To study the in vivo morphology of nasolacrimal duct (NLD) openings into the inferior meatus.
Patients undergoing endoscopic dacryocystorhinostomy and lacrimal intubation had endoscopic real-time examination of the NLD opening. Morphology of NLD openings (size, shape, mucosal folds), and their location from the axilla of the inferior turbinate were assessed.
Forty-three lacrimal systems of 39 adult patients (11 males, 28 females) with a mean age of 61 years were studied. Thirty-five patients had unilateral involvement, and 74% had anatomical NLD obstruction. Of 43 lacrimal systems, 41 had a visible NLD opening. The majority was sulci shaped (63%, 26/41) followed by fissure type (34%), and 2% had wide-open round morphology. The majority of the openings (93%) were oriented vertically, and 67% (14/21) of the sulci shaped openings continued into gutter like channels along the lateral nasal wall. Mucosal folds were present in 7% (3/41) of the openings along the edges. The mean distance between the opening and the axilla of the inferior turbinate was 3.7± 2.1 mm (median, 3.6; range, 0–7.2).
Sulci shaped NLD openings were the most common morphology, and mucosal folds were less commonly observed compared with cadaveric studies.