In vivo confocal microscopy of Meibomian glands in contact lens wearers

Purpose. To evaluate by in vivo laser scanning confocal microscopy (LSCM) the morphologic changes in the meibomian glands (MGs) and the status of periglandular inflammation in contact lens wearers (CLWs) and to investigate the correlations between clinical and confocal findings. Methods. Twenty CLWs and 20 age- and sex-matched control subjects were consecutively enrolled. Each participant completed an Ocular Surface Disease Index questionnaire and underwent a full eye examination, including tear film break-up time, fluorescein and lissamine green staining, and Schirmer test. LSCM of the MGs were performed to determine the cell density of the mucocutaneous junction epithelium, acinar unit density and diameter, glandular orifice diameters, meibum secretion reflectivity, and inhomogeneous appearance of the glandular interstice and acinar wall. Results. All clinical parameters showed statistically significant differences between groups (P < 0.01, Mann-Whitney U test) except the Schirmer test. Confocal data (Mann- Whitney U test) showed significantly decreased basal epithelial cell density (P < 0.01), lower acinar unit diameters (P < 0.05), higher glandular orifice diameters (P < 0.05), greater secretion reflectivity (P < 0.01), and greater inhomogeneity of the periglandular interstices (P < 0.05) in CLWs compared with controls. The duration of contact lens wear was correlated with the acinar unit diameters (P < 0.05, Spearman). Conclusions. Morphologic changes in the MGs shown by LSCM were interpreted as signs of MG dropout, duct obstruction, and glandular inflammation. A comprehensive LSCM evaluation of the ocular surface in CLWs could better clarify the role of MG dropout and eyelid margin inflammation on the pathogenesis of CL-induced dry eye.