Scanning Electron Microscopic Features of the Inferior Meatal Nasolacrimal Duct Openings

Purpose: The aim of this study was to examine the ultrastructural features of the nasolacrimal duct (NLD) openings in the inferior meatus. Methods: Five openings of the NLD in the inferior meati from 5 sagittal head sections of 3 cadavers were studied. Each of the openings were completely excised with 2 mm margins on all sides and transported to the laboratory in 2.5% glutaraldehyde. The analysis was performed using the standard protocols of scanning electron microscopy. The ends, edges, and surfaces were studied along with the mucosal folds, if any, guarding the edge of the openings. Results: Of the 5 NLD openings studied, 4 were of the sulcus variety and 1 was of the shape of a fissure. The fissure opening had a guarding anterior edge mucosal fold. The luminal surfaces of the openings were mostly smooth with focal defined glandular structures. Occasional heterogenous areas with prominent and extensive well-defined glands lined by ciliated columnar epithelium were noted. There were presence of mucosal folds on the floor of the sulci of the openings giving an appearance of a subsulcus. Conclusions: The luminal surfaces of the NLD openings in the inferior meati shows mucosal folds reflected on themselves and cavernous vessels throughout the expanse of the openings. Tear rheology at the NLD opening and the physiologic role of subsulci need to be investigated further. Accepted for publication July 3, 2018. M.J.A. receives royalties from Springer for his treatises "Principles and Practice of Lacrimal Surgery" and "Atlas of Lacrimal Drainage Disorders." The author has no conflicts of interest to disclose. Address correspondence and reprint requests to Mohammad Javed Ali, F.R.C.S., Govindram Seksaria Institute of Dacryology, L.V. Prasad Eye Institute, Hyderabad 500034, Telangana, India. E-mail: drjaved007@gmail.com © 2018 by The American Society of Ophthalmic Plastic and Reconstructive Surgery, Inc., All rights reserved.