In vivo confocal microscopy of meibomian glands in Sjögren's Syndrome

Purpose. To evaluate morphologic changes in meibomian glands (MGs) and the status of periglandular inflammation in patients with primary and secondary Sjogren's Syndrome (SS) using in vivo confocal laser microscopy (LSCM). Methods. Twenty patients with primary SS (SSI), 25 with secondary SS (SSII), 20 with MG dysfunction (MGD), and 25 age- and gender-matched control subjects were enrolled consecutively. Each participant completed an Ocular Surface Disease Index questionnaire and underwent a full eye examination, including tear film break-up time (BUT), fluorescein and lissamine green staining, Schirmer test, and an LSCM examination of the MGs, the last to determine acinar unit density and diameter, glandular orifice diameters, meibum secretion reflectivity, inhomogeneous appearance of glandular interstice, and acinar wall. Results. All parameters indicated statistically significant differences among groups (P <0.001, Kruskal-Wallis test). LSCM demonstrated no differences between SSI and SSII (Mann-Whitney Utest). Compared with control subjects, SS subjects' MGs showed more periglandular inflammation and higher secretion reflectivity (P <0.001, Mann-Whitney U test). Compared with MGD patients, SS patients' MGs had higher acinar density, smaller diameters, greater density of periglandular inflammatory cells, and lower secretion reflectivity (P <0.001, Mann-Whitney U test). In SS patients, the two measured con-focal signs of inflammation were significantly interrelated and correlated with corneal fluorescein staining (P <0.01, Spearman correlation coefficient). Acinar density and diameters were strongly correlated among themselves (P <0.001) and with BUT (P <0.05). Conclusions. LSCM is capable of effectively revealing morphologic and inflammatory changes in MGs and showed discernible patterns of MG abnormalities in SS and MGD not easily distinguishable by the usual clinical exams.