Abstract:AIM: To explore a novel morphological feature of the meibomian gland (MG) and evaluate its prevalence and diagnostic utility in Demodex blepharitis. METHODS: This study included an initial cohort examined for Demodex using in vivo confocal microscopy and an additional validation cohort examined using conventional light microscopy. The new Demodex-infected qualitative (DQ) dropout was defined as the appearance of one or more fully atrophied glands among relatively healthy MG. Diagnostic efficiency was assessed using a receiver operating characteristic (ROC) curve, and diagnostic consistency was tested using Cohen’s kappa. The association between ocular surface parameters and DQ dropout was assessed. RESULTS: The initial cohort included 105 participants, comprising 70 Demodex-positive (DP; 18 males and 52 females; median age, 38y; range, 21–51y) and 35 Demodex-negative (DN; 11 males and 24 females; median age, 33y; range, 24–55y) individuals. The DQ dropout feature was 64.3% and 2.8% in the DP and DN groups, respectively (P<0.001). ROC analysis yielded an area under the curve (AUC) of 0.807. Substantial inter-rater agreement was achieved in confirming DQ dropout, with a Cohen’s kappa of 0.617. In the validation cohort of 887 patients, DQ dropout prevalence remained higher in the DP group than in the DN group (59.9% vs 28.5%, P<0.001), with strong expert agreement (kappa=0.642, P<0.001), and an AUC of 0.671. A multivariable logistic regression model incorporating tear meniscus height, MG area, and energy curve achieved an AUC of 0.969. CONCLUSION: This novel morphological feature of DQ dropout is common in Demodex infection, demonstrating good diagnostic ability and substantial inter-observer agreement.
