Anteroplacement of the Mucocutaneous Junction and Goblet Cell Expansion: Microanatomic Remodeling of the Human Eyelid Margin

Purpose: The mucocutaneous junction (MCJ) plays a vital role in maintaining ocular surface health and integrity. However, the corresponding histopathological changes of the MCJ in human eyelids remain unclear. This study aimed to investigate the pathological alterations of the MCJ and their relationship with meibomian gland (MG) morphology and advancing age. Methods: Tarsal plates (TPs) were obtained from 18 cadaveric donors aged 25 to 90 years. Infrared meibography was performed to evaluate MG morphology. Specimens were processed for histology and immunofluorescence to assess lid margin structures. Quantitative analyses of lid margin parameters, including the MCJ displacement, width of MCJ and lid wiper, goblet cell (GC) density in the lid wiper, and the presence of GCs at the MCJ and MG orifice (MGO) were conducted. Results: Histological analysis identified four progressive grades of MCJ displacement (0-3) in human eyelids, with the average grade increasing significantly with age. In eyelids with MCJ anteroplacement, palpebral conjunctival GC clusters were predominantly located near the anterior lid margin and occasionally extended into MGOs. The muscular conjunctival area ratio of the MG revealed spatially non-uniform distribution patterns in sagittal TP, and, importantly, correlated with the extent of the MCJ shift, indicating that MCJ anteroplacement involves reorganization of the MG within the TP. Conclusions: Our findings suggest that conjunctivalization, accompanied by palpebral GC expansion at the MCJ and MGO, may be a function of age-related MCJ anteroplacement. MCJ anteroplacement and reorganization of the MG provides a plausible histopathological link among lid margin anatomy, MG morphology, and ocular surface ecology.