Presentation of Meibomian Acini Compared to Dermal Papillae of the Eyelid Margin, Using Confocal Laser Scanning Microscopy and Corresponding Histology

Abstract

Background Numerous studies have investigated the eyelid margin using confocal laser scanning microscopy (CLSM) and have presented morphological alterations of the examined structures, which were presumed to be Meibomian acini. However, recent data confirm that these structures are the cross-sections of dermal papillae of the dermoepidermal junction. This study aims to present the morphological appearance of Meibomian acini examined by confocal laser scanning microscopy in comparison to dermal papillae, and to reveal the corresponding patterns with specific histological sections.

Methods and Material Twenty healthy patients were examined with a CLSM device in vivo at the marginal edge of the eyelid. Twenty-two samples of full-thickness eyelid wedges from 22 patients treated surgically with ectropion were collected, of which 11 freshly excised samples were imaged on the incision surface with CLSM ex vivo and 11 eyelids underwent conventional histological preparation. The represented structures on CLSM images were compared to Meibomian acini on histological sections in terms of area, longest and shortest diameter, as well as depth and density.

Results On in vivo CLSM images, Meibomian orifices, epidermal cells, and dermal connective tissue could be identified, the latter in a cross-sectional view of the dermal papillae surrounded by basal cells of the epidermis, forming reflective ring-like structures. All morphological parameters of these structures differed from Meibomian acini measured on histological sections. In contrast, the CLSM images of the incision surface showed acinar units with the same morphology as the Meibomian acini seen in the histological images and no statistically significant difference was found between the corresponding parameters.

Conclusion The morphological appearance of Meibomian acini differs from the structures that were previously presumed as Meibomian glands on CLSM images. In vivo imaging of Meibomian glands by commonly used in vivo CLSM cannot be performed.

Zusammenfassung

Hintergrund Zahlreiche Studien haben den Lidrand mittels konfokaler Laser-Scanning-Mikroskopie (CLSM) untersucht und gewisse morphologischen Veränderungen der untersuchten Strukturen gezeigt, die als vermutliche Meibom-Azini angesprochen wurden. Neueste Daten jedoch bestätigen, dass diese Strukturen Querschnitte von dermalen Papillen der dermoepidermalen Verbindungen sind. Ziel dieser Studie ist es, die Morphologie von Meibom-Azini, die mit konfokaler Laser-Scanning-Mikroskopie untersucht wurden, im Vergleich zu dermalen Papillen darzustellen und die entsprechenden Muster mit spezifischen histologischen Schnitten aufzuzeigen.

Material und Methoden 20 gesunde Patienten wurden mit dem CLS-Mikroskop in vivo am Augenlidrand untersucht. Des Weiteren wurden 22 Proben von Lidkeilen in voller Dicke von 22 Patienten gesammelt, die aufgrund von Ektropium chirurgisch behandelt wurden, 11 frisch entnommene Proben davon wurden auf der Schnittoberfläche mit CLSM ex vivo untersucht, die anderen 11 Augenlidproben wurden nach herkömmlicher Präparation histologisch untersucht. Die auf CLSM-Bildern dargestellten Strukturen wurden hinsichtlich der Fläche, dem längsten und kürzesten Durchmesser sowie der Tiefe und Dichte mit Meibom-Azini auf histologischen Schnitten verglichen.

Ergebnisse Auf In-vivo-CLSM-Bildern konnten Meibom-Öffnungen, Epidermiszellen und dermales Bindegewebe festgestellt werden, letzteres in einem Querschnitt der Hautpapillen, die von Basalzellen der Epidermis umgeben sind und reflektierende ringartige Strukturen bilden. Alle morphologischen Eigenschaften dieser Strukturen unterschieden sich von den an histologischen Schnitten untersuchten Meibom-Azini. Im Gegensatz dazu zeigten die CLSM-Bilder der Schnittoberfläche Azinuseinheiten mit derselben Morphologie wie die Meibom-Azini in den histologischen Bildern, im Vergleich der entsprechenden Parameter ohne einen signifikanten statistischen Unterschied.

Schlussfolgerung Das morphologische Erscheinungsbild der Meibom-Azini unterscheidet sich von den Strukturen, die zuvor auf CLSM-Bildern als Meibom-Drüsen vermutet wurden. Eine In-vivo-Darstellung von Meibom-Drüsen mittels herkömmlichen In-vivo-CLSM kann bis heute nicht durchgeführt werden.

Conclusion Box

Already known:

• In vivo confocal microscopy is capable of imaging structures at the marginal edge of the eyelid, which have been presented as Meibomian acini previously.

• Although it was revealed that these structures are the cross-sections of dermal papillae at the dermoepidermal junction, the morphological appearance of the Meibomian acini examined by confocal microscopy has not been presented yet.

Newly described:

• In our study, we have introduced the native structure of Meibomian acini using images obtained through confocal microscopy for the first time in literature.

• There are major morphological differences between the confocal microscopic image of Meibomian acini and the structure previously presented as Meibomian acini, which corresponds to the cross-sectional image of dermal papillae.

• The feasibility of conducting in vivo examinations of Meibomian glands using the commonly employed 670 nm wavelength confocal microscopy is not possible.

Keywords

Meibomian glands - confocal laser scanning microscopy - dermal papillae - dermoepidermal junction - eyelid

Schlüsselwörter

Meibom-Drüsen - konfokale Laser-Scanning-Mikroskopie - dermale Papillen - dermoepidermaler Übergang - Augenlid

Publication History

Received: 05 November 2022

Accepted: 01 April 2024

Article published online:
27 May 2024

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