Functional and Morphological Evaluation of Meibomian Glands in the Assessment of Meibomian Gland Dysfunction Subtype and Severity.

PURPOSE: To classify subtypes of meibomian gland dysfunction (MGD) and evaluate the dependency of dry eye signs, symptoms, and parameters on MGD subtype. DESIGN: Cross-sectional study. STUDY POPULATION: the right eyes of 447 patients with MGD of various subtypes and 20 healthy volunteers. METHODS: Patients were divided into 4 subtypes of MGD based on meibum expression, meibum quality, and MG loss on meibography images (meibograde of 0-6). Subtypes were patients with high meibum delivery (hypersecretory and nonobvious MGD) and those with low meibum delivery (hyposecretory and obstructive MGD). Additional clinical tests included tear film break-up time (TFBUT), ocular staining, osmolarity, Schirmer I, blink interval timing and the Ocular Surface Disease Index (OSDI) questionnaire. RESULTS: A total of 78 eyes had hypersecretory MGD; 49 eyes had nonobvious MGD; 66 eyes had hyposecretory MGD; and 254 eyes had obstructive MGD. Increased tear film osmolarity and lower TFBUT were found in the low-delivery groups; hyposecretory (P = 0.006, P = 0.016) and obstructive MGD (P = 0.008, P = 0.006) relative to high-delivery MGD (hypersecretory and nonobvious groups, respectively). Worse ocular symptoms and ocular staining were also found in low-delivery MGD groups than the high delivery MGD groups (P < 0.01 and P < 0.006, respectively). CONCLUSIONS: Patients with low-delivery MGD had worse dry eye parameters and ocular symptoms than those with high meibum delivery, indicating the pivotal role of meibum secretion in ocular surface health that should be targeted in MGD therapy. Furthermore, nonobvious MGD cannot be diagnosed using conventional dry eye tests and requires morphologic assessment of meibography images to confirm MG loss.

Prediction of potential drugs and targets based on meibomian gland dysfunction module classification to guide individualized treatment.

Meibomian gland dysfunction (MGD) is an epidemic chronic ocular inflammation. However, little is known about its effective treatment. Here, this study identified important MGD-related genes, core regulators, and potential drugs and their targets though integrating a series of bioinformational analyses. First, there were 665 differentially expression genes (DEGs) were identified. Then, 56 coexpression modules were exacted based on the expression of DEGs and their interactors. Moreover, core transcription factors (TF) significantly regulated modules were identified, including RELA, HIF1A, SIRT1, and MYC, which related to variety of eye diseases. Finally, the prediction of potential drugs and the identification of their target were performed. The results showed that artenimol, copper, and glutathione may have the remarkable curative effect or the toxicology to MGD. Moreover, their targets module gene LDHA (lactate dehydrogenase A), ENO1 (enolase 1), ALB (albumin), and PKM (pyruvate kinase M) are play important role in eye diseases. It suggests that these potential drugs may be useful for the treatment of MGD by acting on their targets. It provides valuable references for drug redirection and new drug development for drug developers, and provides individualized treatment strategies for tarsal gland dysfunction.

In vivo confocal microscopy classification in the diagnosis of meibomian gland dysfunction.

AIM: Meibomian gland dysfunction (MGD) is one of the most common disorders in ophthalmology. The aim of this study was to evaluate the use of this in vivo confocal microscopy (IVCM)-MGD description to classify patients affected by clinical MGD and measure the correlation with standard clinical criteria and subjective symptoms. METHODS: One hundred eyes of 100 patients suffering from MGD and 15 eyes of normal subjects were included. A comprehensive evaluation with the ocular surface disease index (OSDI), Schirmer test, tear break-up time (TBUT), tear osmolarity, Oxford score, Meibomian gland expression, palpebral IVCM, and meibography was performed. Then each patient was classified using a new IVCM classification: type 0 for normality, type 1 for meibum obstruction, type 2 for inflammation, and type 3 for fibrosis. RESULTS: The mean age of patients was 52 ± 20 years old, the OSDI was 38 ± 23, the BUT 5 ± 2.6 s, the Schirmer test 13 ± 7 mm, tear osmolarity 300 ± 11 osmol/L, the Oxford score 0.5 ± 0.6, the meibum expression score 1.7 ± 1.02, and the meibography score 1.3 ± 0.9. The IVCM MG classification of the 15 normal subjects was 0. For MGD patients, 29% were in type 1, 40% were type 2, and 31% were type 3. The patients in IVCM MG type 2 had a higher OSDI (p = 0.001) compared with the other types. There was a strong correlation between the IVCM score and the meibography score (r = 0.71 p < 0.0001). CONCLUSION: This new IVCM classification provided a practical pathophysiological system for MGD. By giving objective criteria, this IVCM classification may help advance the understanding of patients' symptoms and enhance treatment effectiveness in MGD.