Meibomian Gland Dysfunction Group Research Articles

Categorization of Meibomian Gland Dysfunction Using Lipid Layer Thickness and Meibomian Gland Dropout in Dry Eye Patients: A Retrospective Study.

In the present study, we determined the prevalence of obstructive meibomian gland dysfunction (MGD), hyposecretory MGD, grossly normal MG, and hypersecretory MGD in patients with dry eye syndrome using lipid layer thickness (LLT) and MG dropout. Eighty-eight patients with dry eye syndrome were included in the study. Patients were categorized into four groups according to the LLT and weighted total meiboscore. The proportion of patients in each group was calculated. The age, sex, Ocular Surface Disease Index, LLT, Schirmer, tear film breakup time, cornea stain, weighted total meiboscore, expressibility, and quality of meibum were compared between the four groups. Fifteen eyes (17.0%) had obstructive MGD, two eyes (2.3%) had hyposecretory MGD, 40 eyes (45.5%) had grossly normal MG, and 17 eyes (19.3%) had hypersecretory MGD. The obstructive MGD group was younger than the grossly normal MG group. In obstructive MGD, the ratio of men to women was higher than that of the other groups. However, Ocular Surface Disease Index, Schirmer, tear film breakup time, and corneal stain did not show statistically significant differences between the four groups. The meibum expressibility of the hyposecretoy MGD group was worse than those of the other groups. The meibum expressibility of the hyposecretoy MGD group was poor than those of the obstructive and hypersecretory MGD group. This categorization was expected to help determine the best treatment method for dry eye syndrome, according to the MG status.

Composition and diversity of meibum microbiota in meibomian gland dysfunction and the correlation with tear cytokine levels.

Meibomian gland dysfunction (MGD) leads to meibum stasis and pathogenic bacteria proliferation. We determined meibum microbiota via next-generation sequencing (NGS) and examined their association with tear cytokine levels in patients with MGD. This cross-sectional study included 44 moderate-severe patients with MGD and 44 healthy controls (HCs). All volunteers underwent assessment with the ocular surface disease index questionnaire, Schirmer without anesthesia, tear break-up time, Oxford grading of ocular surface staining, and lid and meibum features. Sample collection included tears for cytokine detection and meibum for 16S rRNA NGS. No significant differences were observed in the α-diversity of patients with MGD compared with that in HCs. However, Simpson's index showed significantly decreased α-diversity for severe MGD than for moderate MGD (p = 0.045). Principal coordinate analysis showed no significant differences in β-diversity in meibum samples from patients with MGD and HCs. Patients with MGD had significantly higher relative abundances of Bacteroides (8.54% vs. 6.00%, p = 0.015) and Novosphingobium (0.14% vs. 0.004%, p = 0.012) than the HCs. Significantly higher interleukin (IL)-17A was detected in the MGD group than in the HC group, particularly for severe MGD (p = 0.008). Although Bacteroides was more abundant in the MGD group than in the HC group, it was not positively correlated with IL-17A. The relationship between core meibum microbiota and tear cytokine levels remains unclear. However, increased Bacteroides and Novosphingobium abundance may be critical in MGD pathophysiology.

Ocular microbiome changes in dry eye disease and meibomian gland dysfunction

The most common and chronic ocular problem of aging is dry eye disease (DED) and the associated condition of meibomian gland dysfunction (MGD). The resident ocular surface bacteria may have a role in maintaining homeostasis and perturbation may contribute to disease development. The aim of this study was to compare the microbiomes of the conjunctiva and eyelid margin in humans with mild and moderate DED and controls using 16 S rRNA gene sequencing. The conjunctiva and lid margin of three cohorts (N = 60; MGD, MGD with lacrimal dysfunction [MGD + LD] and controls) were swabbed bilaterally three times over three months. Microbial communities were analysed by extracting DNA and sequencing the V3–V4 region of the 16 S ribosomal RNA gene using the Illumina MiSeq platform. Sequences were quality filtered, clustered into amplicon sequence variants (ASVs) using UNOISE algorithm and taxonomically classified using a Bayesian Last Common Ancestor (BCLA) algorithm against the GTDB 2207 database. The overall microbial communities of the MGD, MGD + LD and control groups were significantly different from each other (P = 0.001). The MGD and MGD + LD dry eye groups showed greater variability between individuals compared to the control (PERMDISP, P < 0.01). There was decreased richness and diversity in females compared to males for the conjunctiva (P < 0.04) and eyelid margin (P < 0.018). The conjunctiva in the MGD + LD group had more abundant Pseudomonas azotoformans, P. oleovorans and Caballeronia zhejiangensis compared to MGD and control (P < 0.05), while the MGD group had more abundant Corynebacterium macginleyi and C. kroppenstedtii compared to control (P < 0.05). The lid margin in MGD was more abundant in C. macginleyi, C. accolens, and C. simulans compared to the MGD + LD and control (P < 0.05). There were differences in the overall microbial community composition and certain taxa, including increased levels of lipophilic bacteria, on the conjunctiva and eyelid margin in mild to moderate DED/MGD compared to controls. DED/MGD was also associated with a reduced bacterial richness and diversity in females.

Automatic segmentation and quantified analysis of meibomian glands from infrared images.

An algorithm for automated segmentation of meibomian glands from infrared images obtained using a novel prototype infrared hand-held imager has been proposed in this study. Meibomian gland dysfunction (MGD) is quantified in terms of five clinically relevant metrics. A comparison of these metrics in patients with MGD has been presented against a sample of the normative healthy population. This is a prospective cross-sectional observational study. Patients presenting to the clinics were enrolled after written informed consent. The everted eyelids of 200 eyes of patients (of which 100 were healthy and 100 were diagnosed with MGD) were imaged using a prototype hand-held camera. The proposed algorithm was used to process the images using enhancement techniques and the glands were automatically segmented. A comparison of glands of normal eyes versus MGD-affected eyes is performed using five metrics presented in this study: (i) drop-out, (ii) length, (iii) width, (iv) the number of glands, and (v) the number of tortuous glands. The 95% confidence interval for the metrics did not show any overlap between the two groups. In MGD patients, the drop-out ratio was higher than normal. The length and number of glands were significantly lesser than normal. A number of tortuous glands were more in the MGD group. The metrics for MGD versus healthy and cut-off ranges were computed in the results. The prototype infrared hand-held meibographer and the proposed automatic algorithm for gland segmentation and quantification are effective aids in MGD diagnosis. We present a set of five metrics, which are clinically relevant for guiding clinicians in the diagnosis of MGD.

Correlation Between Air Quality Index and Tear Film Lipid Layer Thickness: Comparison Between Patients with Sjogren’s Syndrome and with Meibomian Gland Dysfunction

Purpose To evaluate the effect of air pollution on the tear film stability by analyzing the correlation between Air Quality Index (AQI) and Lipid Layer thickness (LLT) in Xuzhou. Methods As a prospective descriptive observational study, 284 patients with meibomian gland dysfunction (MGD), 157 patients with Sjögren’s syndrome (SS), and 264 healthy volunteers were included. The tear film lipid layer thickness of the three groups of subjects was measured weekly and compared with the air quality index to analyze the correlation between the two indicators. Logistic regression analysis and linear regression analysis were used to analyze the effect of AQI on the thickness of the tear film lipid layer. The change of LLT with air pollution at different AQI levels was also analyzed. Results There are obvious seasonal differences in the changes of air pollution index in Xuzhou. Significant differences could be observed in the thickness of the lipid layer of the tear film among the three groups. LLT in the MGD group and SS group decreased with the aggravation of air pollution, while remained unchanged in the control group. There was strong evidence of correlation between LLT of the MGD group (F = 353.494, p < 0.01, adjusted R2 = 0.695) and the SS group (F = 502.404, p < 0.01, adjusted R2 = 0.764) with AQI, while there was minor correlation between LLT with AQI in control group (F = 8.525, p < 0.01, adjusted R2 = 0.046). Conclusions Air pollution can cause a decrease in the thickness of the tear film lipid layer, thereby affecting tear film stability, leading to the occurrence of dry eye.

Metagenomic nanopore sequencing of ocular microbiome in patients with meibomian gland dysfunction.

To explore the composition of the ocular microbiome in patients with Meibomian gland dysfunction (MGD) using metagenomic nanopore sequencing. A total of 98 participants were recruited from September to December 2021, including 86 patients with MGD and 12 controls. Symptoms and signs of dry eye were assessed, and bacterial samples in the conjunctival sac (CS) and meibomian gland (MG) secretions were then identified by bacterial culture identification and metagenomic nanopore sequencing. The positive rate of CS bacterial culture in the MGD group was significantly higher than that in the normal group. A more complex composition of bacterial genera was detected in the mild and moderate MGD groups than in the control. However, the severe MGD groups had the simplest composition of bacteria. Metagenomic nanopore sequencing detected more species of bacteria than traditional culture. The CS and MG of MGD patients may have different degrees of bacterial microbiota imbalance. Metagenomic nanopore sequencing technology provides a new way for us to understand the composition of "real-world" ocular surface microorganisms.

The Effect of Meibomian Gland Dysfunction on Laser-Assisted InSitu Keratomileusis in Asymptomatic Patients.

To evaluate the impact of asymptomatic meibomian gland dysfunction (MGD) on laser-assisted insitu keratomileusis (LASIK) outcomes and dry eye signs and symptoms. A retrospective analysis of patients who underwent LASIK surgery between July 2017 and February 2018 at Care Vision Refractive Clinic, Tel Aviv, Israel, was done. Patients were divided into those who had preoperative asymptomatic significant MGD (MGD group) and those who did not have preoperative significant MGD (control group). Outcomes were the postoperative presence of punctate epithelial erosions, dry eye symptoms, the number of postoperative visits as a measure of adverse events, visual acuity, spherical equivalent, safety index, efficacy index, and the type of refractive error (myopia or hyperopia). A total of 497 eyes were included in this study. Both groups had similar rates of punctate epithelial erosions, 30 (12.9%) patients vs. 39 patients (14.8%) (p = 0.31); postoperative complaints of dryness, 75 patients (32.3%) vs. 90 patients (34.2%) (p = 0.36); and postoperative number of visits, 3.15 ± 0.75 vs. 3.12 ± 0.54 (p = 0.59). Uncorrected visual acuity (logMAR) at 1month (0.026 ± 0.09 vs. 0.026 ± 0.17, p = 0.99) after surgery was similar in both groups. Mean spherical equivalent was 0.03 ± 0.17 and - 0.03 ± 0.18 (p = 0.99) in both groups. Safety index was 1.024 ± 0.06 in the clinically significant MGD group and 1.029 ± 0.07 in the control group (p = 0.45). Efficacy index was also similar in both groups (0.966 ± 0.155 and 0.979 ± 0.14, respectively, p = 0.31). No differences were found between patients with myopia and hyperopia. Patients with preoperative asymptomatic MGD have similar LASIK outcomes to patients without preoperative asymptomatic MGD. Accordingly, no preoperative MGD treatment or special caution is needed in these cases.

Evaluation of the Tear Meniscus Using Optical Coherence Tomography in Meibomian Gland Dysfunction

ABSTRACT Introduction This study aimed to evaluate tear meniscus parameters in meibomian gland dysfunction (MGD) using optical coherence tomography and ImageJ software. Methods We enrolled 66 eyes of 66 participants and measured tear meniscus parameters, including height, depth, turbidity, and percentage area occupied by particles (PAOP) in the meniscus in the MGD and control groups. Results Tear meniscus turbidity and PAOP were significantly higher in the MGD group, but tear meniscus height (TMH) and depth (TMD) did not differ significantly between groups. Tear meniscus turbidity and PAOP were positively correlated with each other and ocular surface parameters, including OSDI and ocular surface staining scores. Conclusion Tear meniscus turbidity and PAOP were higher in the MGD group than in the control group; therefore, they can be used as significant non-invasive parameters in the prediction of MGD. TMH and TMD did not differ significantly between groups.

Impact of meibomian gland dysfunction on quality of life and mental health in a clinical sample in Ghana: a cross-sectional study.

ObjectivesThis study aimed to determine the impact of meibomian gland dysfunction (MGD) on quality of life and psychosomatic conditions.DesignThis was a clinic-based cross-sectional study.SettingThis study was conducted at the eye clinic of the University of Cape Coast, Ghana.Participants215 clinical subjects visiting the clinic for a comprehensive eye examination.Primary and secondary outcome measuresSymptomatic MGD, asymptomatic MGD, quality of life scores, depression, anxiety and stress.Results215 clinical subjects consented to participate in the study, but 212 were included in the analysis. The mean age was 21.9 (± 3.8) years, 54 had MGD and 158 did not have MGD served as controls. There was no statistically significant difference in the mean quality of life scores between subjects with MGD and subjects without MGD (t=1.57, p=0.12). The quality of life scores (DEQS) (p=0.022) were significantly higher in the symptomatic MGD group compared with the asymptomatic MGD group. There was no significant difference in quality of life scores (DEQS) (p=0.251) in the asymptomatic MGD group compared with healthy controls. Using Pillai’s trace in the MANOVA, there was a significant effect of MGD on depression, anxiety and stress (V=0.05, F(3,208)=3.76, p=0.012). Furthermore, Pillai’s trace in the MANOVA showed a significant difference between asymptomatic and symptomatic MGDs for depression, anxiety and stress scores stress (V=0.24, F(3, 51)=5.24, p=0.003).ConclusionThe study revealed no difference in the quality of life scores between MGD and non-MGD groups. However, the symptomatic MGD group had worse quality of life and psychosomatic symptoms than the asymptomatic MGD group and non-MGD group.

Immediate and Quantitative Changes in Tear Film Parameters and Meibomian Gland Structures after Warm Compression and Meibomian Gland Squeezing in Meibomian Gland Dysfunction Patients and Normal Subjects.

Meibomian gland dysfunction (MGD), a chronic abnormality of meibomian glands, causes various dry eye symptoms. Principal treatments for MGD are warm compression and mechanical squeezing of the eyelids. In this study, the immediate impact of this treatment on tear film lipid layer thickness (TFLLT) and the meibomian gland (MG) structure in MGD and normal groups was investigated to establish its efficacy and potential side effects. Nineteen MGD patients and seven normal subjects were enrolled. TFLLT and blinking parameters were evaluated before and after warm compression. Morphological changes of MG structures after mechanical squeezing were analyzed using Image J and Fiji. Differential analysis of the MGD and the normal groups of TFLLT changes after warm compression showed a significant increase in the normal group. In normal eyes, the average, maximum, and minimum TFLLT were significantly increased, and in the MGD group, only the minimum TFLLT was improved. Blinking parameters showed no significant change in either group. Morphometric analysis showed no damages of the MG after MG squeezing. A significant increase in MG length was observed in normal eyes. Warm compression immediately increased TFLLT more significantly in the normal group than in the MGD patients. Mechanical expression is a safe therapeutic option without remarkable structural MG damages.

In vivo confocal microscopic study of corneal innervation in Sjögren's Syndrome with or without small fiber neuropathy

PurposeTo study changes in the subbasal nerve plexus by In vivo confocal microscopy (IVCM) in Sjögren's Syndrome (SS) with or without associated Small Fiber Neuropathy (SFN), in order to prevent diagnostic delay. MethodsSeventy-one patients with SS, including 19 with associated SFN, 20 healthy volunteers and 20 patients with Meibomian gland dysfunction (MGD) were included in this retrospective case-control study. IVCM was used to investigate subbasal nerve plexus density and morphology. ResultsCorneal sensitivity as evaluated with the Cochet-Bonnet aesthesiometer was significantly reduced in the SS group versus the control group (P = 0.026) and the MGD group (P = 0.037). The number of inflammatory cells was significantly increased in the SS group to 86.2 ± 82.1 cells/mm2 compared to the control group (P < 0.001). The density of the subbasal nerve plexus was significantly reduced to 16.7 ± 6.5 mm/mm2 in the SS group compared to the control group (P < 0.005) and the MGD group (P = 0.042). The tortuosity of the nerves in the SS group was significantly increased compared to the control group (P < 0.001) and the MGD group (P = 0.025). The average number of subbasal nerve plexus neuromas was significantly increased in the SS group compared to the control group (P = 0.001), with a significant increase in the average number of neuromas in SS patients with associated SFN compared to SS patients without SFN (P = 0.008). ConclusionIVCM can be useful to detect corneal nerve changes in SS patients and may allow earlier diagnosis of the disease and to consider new therapeutic approaches.

Evaluation of ocular surface parameters in dogs with and without meibomian gland dysfunction.

Interest in meibomian gland dysfunction (MGD) is growing in veterinary medicine. However, research on MGD in dogs is lacking. The aims of this study were to compare the interferometry grades, tear meniscus height (TMH) and non-invasive tear break-up time (NIBUT) grades between dogs with and without MGD. Routine ophthalmic examination, interferometry, NIBUT assessment, TMH measurement and meibography were performed. Age and Schirmer tear test-1 (STT-1) results were compared between the control and MGD groups using Student's t-test. Interferometry grades, NIBUT grades and TMH were compared between the two groups using Mann-Whitney U-test. There was no significant difference in age between the two groups (p=0.279). STT-1 (p=0.024), interferometry (p=0.004) and NIBUT grades (p=0.012) were significantly lower in the MGD group than in the control group. No significant difference in TMH values (p=0.587) was observed between the two groups. While the control group included 18 and seven eyes in meiboscore 0 and 1, in MGD group, 12, eight, five and three eyes were included in meiboscore 0, 1, 2 and 3, respectively. Low interferometry and NIBUT grades were associated with MGD, suggesting decreased meibum and disrupted tear film quality. TMH did not differ between the two groups. Meibography could aid in the diagnosis of MGD in severe cases, although it could not detect early MGD in the dogs in this study.

Lipid layer thickness decrease due to meibomian gland dysfunction leads to tear film instability and reflex tear secretion

Purpose To determine the clinical effects of ocular surface and Meibomian gland parameters on tear film stability among individuals with Meibomian gland dysfunction (MGD), those with aqueous deficient dry eye (ADDE), individuals with both conditions and normal controls. Methods Patients were divided into four groups: normal controls, patients with ADDE, patients with MGD, and patients who fulfilled diagnostic criteria for ADDE and MGD (Mixed Group). Data for ocular symptom score, lid margin abnormality, ocular staining, tear break-up time, meiboscore, and lipid layer thickness (LLT) measured by a Lipiview interferometer, Schirmer test, and MGD severity score were collected. Results A total of 109 patients (109 eyes) were evaluated. In patients with MGD, LLT was significantly lower than the ADDE patients. However, the Schirmer test value was the highest in the MGD group. The LLT negatively correlated with meiboscore and MGD severity score in the MGD group. Significant correlation between Schirmer test value and meiboscore was definite in the MGD group. Conclusions Tear fluid secretion is more increased and lipid layer thickness is more decreased in MGD patients than in ADDE patients. Decreased lipid layer thickness caused by MGD-related tear film instability may stimulate reflex tear secretion. The obstructive MGD is more prevalent than hypersecretary MGD. Key messages The tear film stability is affected by Mebomian gland dysfunction (MGD). The measurement of the tear film parameters including lipid layer thickness suggests that the obstructive MGD is more prevalent than hypersecretary MGD and the aqueous layer compensates the decreased lipid layer caused by MGD.

Quantitative measurement of optical properties and Hb concentration in a rodent model of inflammatory Meibomian gland dysfunction using spatial frequency domain imaging.

Herein, to investigate a new diagnostic method for Meibomian gland dysfunction (MGD) induced by eyelid inflammation, optical properties and deoxy-hemoglobin (Hb) concentrations in rodent eyelid tissues, including Meibomian glands(MGs), were measured using spatial frequency domain imaging (SFDI). Complete Freund's adjuvant solutions were injected into the eyelid margins of Sprague-Dawley rats to induce MGD. After three weeks, the optical properties and Hb of the MG and non-MG regions of the eyelids were measured ex-vivo using an SFDI system. The comparison of Hb showed that the MGD group exhibited significantly higher values than those of the control group in both regions. The optical properties at 730 and 850 nm for the MG regions in the MGD group were significantly different from those in the control group. In addition, the 630 nm absorption coefficients of both regions were significantly higher in the MGD group than in the control group. Thus, the SFDI technique can detect the increased Hb concentration and changes in the optical properties of the eyelids due to inflammatory MGD in a noncontact manner and has the potential to be used as a novel quantitative diagnostic method for the occurrence of MGD.

A multi-center study evaluating the correlation between meibomian gland dysfunction and depressive symptoms

Increased prevalence of depression has been found in patients with meibomian gland dysfunction (MGD); however, specific conditions of patients suffered from MGD and depression remains unclear. Our aim was to investigate the prevalence of depression in patients with MGD and analyze the risk factors of depression in MGD patients. In this multi-center cross-sectional study, we enrolled 830 MGD patients and 114 normal controls. Demographic information was collected by designed questionnaires about lifestyle habits, systemic and ocular medical history. Ophthalmic examinations were performed in a formal order. Depression symptoms were evaluated with a questionnaire survey using a modified self-rating depression scale (M-SDS). The correlations between the M-SDS score and demographic and clinical information were analyzed. The prevalence of hyperlipidemia and obstructive sleep apnea–hypopnea syndrome (OSAHS) was higher in the MGD group. There were 78 cases (9.4%) with depressive symptoms in the MGD group whereas there were 4 cases (3.5%) in controls. Similarly, M-SDS was higher in the MGD group. The characteristics of depression in the MGD group included: crying spells, sleep disturbance and depressed appetite. Some systemic diseases (OSAHS, allergy, skin disease) and the use of contact lenses was correlated with an increased risk of depressive symptoms in MGD patients.

Noninvasive ocular surface analyzer as an adjunct in diagnosis and estimating prevalence of meibomian gland dysfunction: Hospital-based comparative study.

Purpose:To assess the role of noninvasive ocular surface analyzer (OSA) in workup of meibomian gland dysfunction (MGD) and to estimate hospital-based prevalence of MGD using this objective device.Methods:The study recruited 113 consecutive participants attending the ophthalmology outpatient department of a tertiary care hospital. All participants were administered a symptom questionnaire. Participants underwent a comprehensive ocular examination, including slit-lamp biomicroscopy and meibomian gland expression. Lipid layer thickness (LLT), noninvasive tear breakup time (NIBUT), tear meniscus height (TMH), and meibomian gland loss (MGL) were assessed using OSA. The presence of either or both reduced/absent meibum secretion and cloudy to toothpaste-like secretion was diagnosed as MGD.Results:Prevalence of total MGD was 57.52% (95% confidence interval [95% CI]: 48.3%–66.8%) and that of symptomatic MGD was 42.5% (95% CI: 33.2%–51.7%). Prevalence of total and symptomatic MGD was highest in those aged ≥50 years (P < 0.001 and P = 0.004, respectively). Computer vision syndrome increased the odds of symptomatic MGD (odds ratio [OR]: 4.3). NIBUT and MGL significantly differed in MGD and non-MGD groups (P = 0.023 and P < 0.001, respectively). LLT significantly differed between asymptomatic and symptomatic cases (P = 0.033). MGL >25% increased the odds of having MGD (OR: 19.1). Significant negative correlations were observed between MGL and NIBUT (P = 0.04) and between MGL and LLT (P = 0.02). MGL demonstrated the highest diagnostic accuracy for MGD (AUC = 0.827, sensitivity = 75.4%, specificity = 85.4%, cut-off value: ≥26%).Conclusion:MGD is a common disorder in adults attending the ophthalmology outpatient services of a tertiary eye care hospital. Incorporating noninvasive OSA in clinical practice can aid in rapid and reliable measurements of MGD-related parameters.

Characterization of the thickness of the Tear Film Lipid Layer in Meibomian Gland Dysfunction using high resolution optical microscopy

PurposeTo evaluate the thickness of the tear film lipid layer (TFLL) in meibomian gland dysfunction (MGD) using a high-resolution optical microscope. MethodsThe Ocular Surface Disease Index (OSDI) and meibum grade score (MGS) were used to classify 190 subjects into four groups: normal (OSDI<13 and MGS<10), mixed (OSDI≥13 and MGS<10), asymptomatic MGD (OSDI<13 and MGS≥10), and MGD (OSDI≥13 and MGS≥10). The high-resolution optical microscope was used to capture TFLL images in vivo. The histograms of TFLL thickness were analyzed and curve-fitted using probability density functions (PDFs). ResultsThere were three obvious peaks in the distributions of TFLL across the groups. From the curve-fitting process, the main outcomes are displayed according to each Gaussian function with the position of peak (μ) and the summed percentage within the range of standard deviation (σ). The normal group had distribution as follows: 33.3 ± 0.005 nm, 26%; 53.9 ± 0.019 nm, 40%; 79.4 ± 0.064 nm, 12%. The mixed group had a distribution as follows: 33.8 ± 0.004 nm, 32%; 53.1 ± 0.115 nm, 21%; 71.7 ± 0.232 nm, 27%. The asymptomatic MGD group had a distribution as follows: 33.5 ± 0.004 nm, 20%; 49.2 ± 0.041 nm, 25%; 62.9 ± 0.063 nm, 47%. The MGD group had a distribution as follows: 34.3 ± 0.004 nm, 34%; 53.7 ± 0.022 nm, 28%; 74.9 ± 0.060 nm, 16%. ConclusionsThe MGD and mixed groups had the largest percentages of TFLL thicknesses fall within the thinnest modes (peak 34.3 and 33.8 nm, respectively). These data show that measures of central tendency (e.g., averages, medians) do not fully appreciate the variable distributions of TFLL across disease spectra.

Observation of Conjunctiva-Associated Lymphoid Tissue With In Vivo Confocal Microscopy in Healthy Patients and Patients With Meibomian Gland Dysfunction.

Purpose:The purpose of this study was to assess the distribution and morphological variation of conjunctiva-associated lymphoid tissue (CALT) in healthy human subjects and patients with meibomian gland dysfunction (MGD) using laserscanningin vivo confocal microscopy.Methods:A total of 34 healthy subjects and 32 patients with MGD were enrolled. All subjects underwent a conventional examination consisting of slitlamp biomicroscopy, tear film break-up time, and the Schirmer test. In vivo microscopy was applied to analyze the morphological changes in the diffuse lymphoid layer and lymphoid follicles in CALT. Conjunctival impression cytology (CIC) of samples of patients' palpebral conjunctiva and immunofluorescence staining of CD4 and CD8 antibodies were also performed to indicate the immune response status of CALT.Results:In the MGD group, the density of diffuse lymphocytes (P < 0.001), follicles (P < 0.001), and perifollicular lymphocytes was higher (P < 0.001) and the central reflection of the follicles was stronger (P < 0.001) than in the control group, while there was no difference in the follicle area (P = 0.758). Besides, diffuse lymphocyte density was correlated with telangiectasia, and follicular center reflection intensity was correlated with plugging. CIC immunofluorescence staining showed a higher percentage of CD4+ (P < 0.001) and CD8+ (P < 0.001) cells in the MGD group than in the control group.Conclusions:Using laser scanning in vivo confocal microscopy and CIC immunofluorescence staining, we observed the activation of CALT in patients with MGD, and some CALT-related parameters correlated with the lid margin findings of patients with MGD.

Quantitative analysis of morphological and functional features in Meibography for Meibomian Gland Dysfunction: Diagnosis and Grading.

BackgroundTo explore the performance of quantitative morphological and functional analysis in meibography images by an automatic meibomian glands (MGs) analyser in diagnosis and grading Meibomian Gland Dysfunction (MGD).MethodsA cross-sectional study collected 256 subjects with symptoms related to dry eye and 56 healthy volunteers who underwent complete ocular surface examination was conducted between January 1, 2019, and December 31, 2020. The 256 symptomatic subjects were classified into MGD group (n = 195) and symptomatic non-MGD group (n = 61). An automatic MGs analyser was used to obtained multi-parametric measurements in meibography images including the MGs area ratio (GA), MGs diameter deformation index (DI), MGs tortuosity index (TI), and MGs signal index (SI). Adjusted odds ratios (ORs) of the multi-parametric measurements of MGs for MGD, and the area under the receiver operating characteristic (AUC-ROC) curves of multi-parametric measurements for MGD diagnosing and grading were conducted.FindingsWhen consider age, sex, ocular surface condition together, the estimated ORs for DI was 1.62 (95% CI, 1.29-2.56), low-level SI was 24.34 (95% CI, 2.73-217.3), TI was 0.76(95% CI, 0.54-0.90), and GA was 0.86 (95% CI, 0.74-0.92) for MGD. The combination of DI-TI-GA-SI showed an AUC = 0.82 (P < 0.001) for discriminating MGD from symptomatic subjects. The DI had a higher AUC in identifying early-stage MGD (grade 1-2), while TI and GA had higher AUCs in moderate and advanced stages (grade 3-5). Merging DI-TI-GA showed the highest AUCs in distinguish MGD severities.InterpretationThe MGs area ratio, diameter deformation, tortuosity and signal intensity could be considered promising biomarkers for MGD diagnosis and objective grading.FundingThis work was supported by the Key-Area Research and Development Program of Guangdong Province (No. 2019B010152001), the National Natural Science Foundation of China under Grant (81901788) and Guangzhou Science and Technology Program (202002030412).

Relationship between serum lipid level and meibomian gland dysfunction subtype in Korea using propensity score matching

To analyze the relationship between systemic lipid profile levels and meibomian gland dysfunction (MGD) subtype in Korea. The ophthalmic data of 95 eyes and the serum lipid profiles of 95 patients were reviewed. These factors were compared with those of the general population using data from the Korean National Health and Nutrition Examination Survey (KNHANES), which evaluated 2,917 subjects. Of these, the comparison group (1:5 ratio; n = 475) was selected using propensity score matching according to age and sex. In addition, we analyzed the relationship between serum lipid profile levels and MGD subtypes in MGD patients. The mean high-density lipoprotein (HDL) value of the MGD patients was significantly higher than that of the general population (P < 0.0001). Moreover, the mean low-density lipoprotein (LDL) levels of the MGD patients was significantly lower than that of the general population (P = 0.0002). However, the mean total cholesterol (TC), and triglyceride (TG) levels of the MGD patients were not significantly different from those of the general population (TC: P = 0.4282, TG: P = 0.5613). In addition, no serum lipid levels statistically differed among the MGD subtypes (TC: P = 0.7650, HDL: P = 0.2480, LDL: P = 0.3430, TG: P = 0.7030). A statistically significant increase in HDL and decrease in LDL concentration were observed in the MGD group, although there was no difference in any serum lipid level among the MGD subtypes.