The Efficacy, Sensitivity, and Specificity of In Vivo Laser Confocal Microscopy in the Diagnosis of Meibomian Gland Dysfunction

Abstract

To evaluate the efficacy, sensitivity and specificity of confocal microscopy (CM) parameters: meibomian gland (MG) acinar longest diameter (MGALD), MG acinar shortest diameter (MGASD), inflammatory cell density (ICD), and MG acinar unit density (MGAUD) in the diagnosis of MG dysfunction (MGD). Prospective, controlled, single-center study. Twenty MGD patients (9 males, 11 females; mean age, 63.5+/-16.5 years) and 26 age- and gender-matched control subjects (13 males, 13 females; mean age, 53.2+/-15.7 years) were recruited. All subjects underwent slit-lamp examinations, tear film break-up time (BUT) measurements, assessment of tear evaporation rate from the ocular surface (TEROS), vital stainings, Schirmer test, meibography, MG expressibility, and CM of the MG. Data were compared between the 2 groups using the Mann-Whitney and chi-square tests. The correlation between the clinical findings of tear functions, vital staining scores, and the 4 CM parameters were tested by Spearman's correlation coefficient by rank test. Receiver operating characteristic curve technique was used to evaluate the sensitivity, specificity, and cutoff values of CM parameters. The mean tear film BUT, vital staining scores, TEROS values, MG expressibility, and MG dropout grades by meibography were significantly worse in MGD patients compared with controls (P<0.001). The mean values of the MGALD, MGASD, ICD, and MGAUD in MGD patients were significantly worse than those observed in the controls with CM. All CM parameters showed a strong, significant correlation with tear functions, ocular surface vital stainings, MG expressibility, and MG dropout grades. The cutoff values for MGALD, MGASD, ICD, and MGAUD in the diagnosis of MGD were 65 microm, 25 microm, 300 cells/mm2, and 70 glands/mm2, respectively. The sensitivity and specificity values of these parameters under these cutoff values were 90% and 81% for MGALD, 86% and 96% for MGASD, 100% and 100% for ICD, 81% and 81% for MGAUD. Confocal microscopy has the potential to diagnose the simple MGD with high sensitivity and specificity. The CM-based diagnostic parameters correlated significantly and strongly with the status of the ocular surface disease. The authors have no proprietary or commercial interest in any of the materials discussed in this article.