Evaluation of Meibomian Gland Structure and Function in Patients with Vernal Keratoconjunctivitis Using Non Contact Meibography and Lipid Layer Interferometry.

PURPOSE: This study evaluated the structural and functional impact of vernal keratoconjunctivitis (VKC) on meibomian glands (MGs) using a combination of noncontact meibography and lipid layer interferometry. METHODS: In this observational study 50 patients with moderate persistent or severe VKC and 50 age-matched controls underwent MG imaging and lipid layer thickness (LLT) measurements with Lipiview II. Image J software was used to assess MG loss (meibograde) in both lids. All patients underwent dry eye evaluation comprising tear break-up time (TBUT), ocular surface staining (OSS), Schirmer I scoring, and meiboscoring (expressibility and quality of meibum secreted). RESULTS: Meibograde, OSS score, and meiboscore was higher in cases (2.68 ± 0.96, 0.580 ± 1.07, and 0.56 ± 0.95 respectively) than controls (1.80 ± 0.67, 0.00 ± 0.00, 0.22 ± 0.47 respectively) (p < 0.001, 0.001, 0.025 respectively). LLT and TBUT was lower in cases (54.58 ± 9.43 nm and 4.92 ± 3.09 sec respectively) than controls (70.14 ± 22.50 nm and 12.02 ± 2.73 sec respectively) (both p's = 0.001). Both groups had comparable Schirmer I scores. CONCLUSION: Children with VKC have significant MG dropouts, deterioration in meibum quality and a thinner and less stable tear film. VKC patients are thus prone to a vicious cycle of inflammation attributable both to the allergic component and to deterioration in MG structure and function. Co-management of MG dysfunction warrants as much attention as the allergic component itself.

Topical glaucoma medications - Possible implications on the meibomian glands.

One of the most common causes of blindness on a global scale is glaucoma. There is a strong association between glaucoma and increased intraocular pressure (IOP). Because of this, adequate IOP-lowering is the most important treatment strategy, mostly through topical eyedrops. Well-functioning meibomian glands are paramount for maintaining a stable tear film, and their dysfunction is the most common cause of dry eye disease. There is a growing concern that both topical glaucoma medications themselves and their added preservatives damage the meibomian glands, and consequently, the ocular surface. Preserved topical glaucoma medications appear to cause dysfunction and atrophy of the meibomian glands. Upon comparison, preserved formulations caused more symptoms of dry eye, tear film instability, inflammatory changes and meibomian gland dropout than the preservative-free counterpart. However, although seemingly less detrimental, unpreserved alternatives may diminish glandular efficacy, and, depending on the active ingredient, lead to glandular death. This negatively impacts quality of life, adherence to treatment regimens and prognosis. In this review, we explore the available evidence regarding the effects of IOP-lowering eye drops on the meibomian glands.

Temporal variations in meibomian gland structure-A pilot study.

PURPOSE: To investigate whether there is a measurable change in meibomian gland morphological characteristics over the course of a day (12 h) and over a month. METHODS: The study enrolled 15 participants who attended a total of 11 study visits spanning a 5-week period. To assess diurnal changes in meibomian glands, seven visits were conducted on a single day, each 2 h apart. For monthly assessment, participants attended an additional visit at the same time of the day every week for three consecutive weeks. Meibography using the LipiView® II system was performed at each visit, and meibomian gland morphological parameters were calculated using custom semi-automated software. Specifically, six central glands were analysed for gland length ratio, gland width, gland area, gland intensity and gland tortuosity. RESULTS: The average meibomian gland morphological metrics did not exhibit significant changes during the course of a day or over a month. Nonetheless, certain individual gland metrics demonstrated notable variation over time, both diurnally and monthly. Specifically, meibomian gland length ratio, area, width and tortuosity exhibited significant changes both diurnally and monthly when assessed on a gland-by-gland basis. CONCLUSIONS: Meibomian glands demonstrated measurable structural change over short periods of time (hours and days). These results have implications for innovation in gland imaging and for developing precision monitoring of gland structure to assess meibomian gland health more accurately.

Evaluation of visual field and ocular surface parameters by clinical comparison after blepharoplasty for dermatochalasis.

PURPOSE: To evaluate the effect of upper eyelid blepharoplasty surgery on corneal topography, visual field, ocular surface, meibography, corneal biomechanics and dry eye parameters. METHODS: This prospective study included a total 80 eyes of 40 patients. Following a detailed ophthalmological examination, standardized patient satisfaction questions were posed to patients before and after upper eyelid blepharoplasty surgery. Visual field test, non-invasive break up time (NIBUT), meibography, and corneal topography parameters were analyzed and evaluated. RESULTS: The mean (+) visible areas in the visual field were found to be 46.20±24.96 preoperatively, 56.73±21.98 at the 1st postoperative month and 65.96±18.5 at the 3rd month, which were statistically significant. NIBUT values preoperatively, at 1 month and at 3 months were 11.26±4.48, 11.16±4.5 and 10.14±4.0, respectively, which were statistically significant. Meibomian gland loss rates on meibography preoperatively and postoperatively at 1 and 3 months were found to be 30.24±8.3, 29.36±8.2 and 28.22±7.7 respectively and were statistically significant. With the scoring system after blepharoplasty, patients reported improvement in their symptoms. CONCLUSION: Upper eyelid blepharoplasty surgery is predicted to increase the quality of vision. It was observed that there was a functional and cosmetic improvement in the complaints of the patients after blepharoplasty. However, blepharoplasty may cause changes in eyelid dynamics and cause dry eye syndrome.

The Use of Infrared Auto Refractometer for Meibomian Gland Imaging.

Introduction This study proposes the utility of an infrared auto refractometer for meibography and compares miebographs obtained by an auto refractometer to meibographs obtained by a designated meibography machine. Methods A prospective observational comparative study of meibographs of patients with clinical signs of meibomian gland dysfunction (MGD) using a designated meibography machine and an infrared auto refractometer. Five masked, experienced interpreters graded the images of the two machines. The Kappa test was used to calculate Intra-rater and inter-rater agreements between the meibography machine and automated refractor grading of meibomian gland dysfunction. Results High-quality photos of all 30 eyes delineating the meibomian glands (MG) were successfully obtained with both the meibography machine and the autorefractor. Both methods had a good intra-rater agreement (κ= 0.667 to 0.784, average 0.738). Poor to fair interrater agreement was noticed in the grading of autorefractor images (k= -0.030 to 0.343, average 0.092) and poor to moderate agreements between investigators for meibography machine images (K= -0.016 to 0.420, average 0.173). Conclusion A commercially available auto refractometer could capture high-quality non-contact IR digital meibographs.

Standardization of meibomian gland dysfunction in an Egyptian population sample using a non-contact meibography technique.

AIM: To develop normative data for meibomian gland dysfunction (MGD) parameters, using non-contact meibography technique of Sirius Costruzione Strumenti Oftalmici (CSO) machine, in an Egyptian population sample. METHODS: Observational, cross-sectional, analytic study, in which 104 Egyptian volunteers were included. Both upper lids were examined, using "Sirius CSO" machine. Each eyelid was given a degree of meibomian gland loss (MGL), which was calculated by the software of the machine. RESULTS: Mean percentage MGL in right upper lid was of 30.9%±12.6%, and that of left upper lid was 32.6%±11.8%. Thirty-four volunteers (32.7%) had first-degree MGL in their right upper lid, and 67.3% had second-degree loss. One volunteer (1%) had zero-degree MGL in left upper lid, 28 (26.9%) had first-degree loss, and 75 (72.1%) had second-degree loss. Degree of MGL in right upper eyelid was not related to age, but degree of MGL in left upper eyelid increased with age. There was statistically significant difference between both genders for degree of MGL in right eye (P=0.036) and in left eye (P=0.027). CONCLUSION: Noncontact meibography is a useful non-invasive tool for diagnosing MGL. MGL is diagnosed in 100% of apparently normal individuals; 26.9%-32.7% of which have first-degree MGL, and 67.3%-72.1% have second-degree MGL.

Association of ocular surface and meibomian gland alterations with silicone hydrogel contact lens wear.

PURPOSE: To evaluate silicone hydrogel contact lens (SH-CL) effects on the meibomian glands, corneal structure, and ocular surface parameters. METHODS: Fifty SH-CL wearers for at least 6 months, and 50 sex and age-matched control subjects were recruited for this cross-sectional study. Visual display terminal (VDT) work and CL wear duration were questioned, ocular surface and tear functions were evaluated using OSDI questionnaire, tear break-up time (TBUT), corneal fluorescein staining, and Schirmer test. Corneal sensitivity was measured with Cochet-Bonnet aesthesiometry. Meibography and in vivo confocal microscopy (IVCM) were performed to evaluate meibomian glands and corneal structure. Intergroup comparisons were made using the Chi-square test, Wilcoxon test, or Kruskal-Wallis test. RESULTS: In the CL group, TBUT was shorter (P = 0.01), corneal fluorescein staining (P = 0.04), OSDI scores (P < 0.001), and meiboscores (P < 0.001) were higher than the control group. The biomicroscopic evaluation revealed meibomian gland dysfunction (MGD) in 34 % of the CL group and 20 % of the control group, which was not statistically significant (P > 0.05). IVCM showed that endothelial cell density was lower (P = 0.01) and polymegethism was higher (P < 0.001) in the CL group. Subbasal nerve density and corneal sensitivity measurements were similar in the two groups (P > 0.05). The longer VDT work duration was associated with increased CFS in the CL group (P = 0.05). CONCLUSION: The results showed that SH-CL wear increased dry eye symptoms and ocular discomfort, especially in longer VDT work duration. Meibography revealed significantly worse results in SH-CL wearers. SH-CL-related ocular discomfort seems to be more associated with MGD rather than neurosensorial alterations.

Anterior segment optical coherence tomography meibography compared with keratograph meibography.

PURPOSE: The aim of this study was to determine the feasibility of using readily accessible technology, anterior segment optical coherence tomography (AS-OCT), to detect and grade meibomian gland dropout and examine its interchangeability with the Oculus Keratograph 5M (K5M). METHODS: A total of 30 participants (30 eyes) with a median age of 21 (range = 19-28 years) were recruited. Meibography was performed using two commercially available imaging devices to look at the structure of the meibomian glands and grade them subjectively in real time, and image analysis was used to quantify meibomian gland loss objectively. Gland loss as imaged by the two techniques was graded using the meiboscore grading schema. Test-retest reliability was determined with intraclass correlation coefficients (ICCs). Weighted kappa was used to evaluate agreement between the two imaging devices and four methods of image analysis. Spearman and Pearson correlation coefficients were used to determine the association of structural measurements between each of the techniques. The agreement between the two imaging techniques was determined with the Bland-Altman analysis. RESULTS: Reliability of subjective grading was strong for AS-OCT (ICC: 0.92, 95% CI: 0.83-0.96, p < 0.001) and K5M (ICC: 0.96, 95% CI: 0.96-0.91, p = 0.001). Image analysis with ImageJ reliability was strong between the imaging devices (ICC: 0.84, 95% CI: 0.55-0.94, p < 0.001). Agreement between each subjective technique was fair, κ = 0.45 (95% CI: 0.17-0.73, p < 0.001) and a positive Spearman correlation was also observed (r = 0.52, p < 0.001). There was no significant difference between the mean meibomian gland loss measured with ImageJ between AS-OCT and K5M (0.92 ± 6.28, p = 0.26). The 95% limits of agreement were -12.45% to +14.04%. CONCLUSION: These findings suggest subjective real-time grading of meibomian gland loss could be performed using readily available AS-OCT technology and that this method was interchangeable with the K5M.

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

PURPOSE: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: This categorization was expected to help determine the best treatment method for dry eye syndrome, according to the MG status.

Non-contact meibography changes according to disease activity in rheumatoid arthritis cases.

PURPOSE: To measure dry eye disease (DED) activity in rheumatoid arthritis (RA) patients, correlate it with the activity and duration of RA, and objectively measure the degree extent of DED in RA active cases. METHODS: The paper studied the meibomian gland of 30 RA cases referred by the Rheumatology Department, Sohag University Hospitals to Sohag Cornea and Refractive Center, Sohag, Egypt, by infrared non-contact meibography in the Scheimpflug topographer (Sirius, CSO, Italy) from July 2021 to July 2022. The cases fulfilled the RA classification criteria according to the 2010 American College of Rheumatology and European League and underwent full lab investigations. They were distributed to two groups based on the DAS-28 questionnaire. The patients were distributed into low to moderate activity (3.2 < score < = 5.1) and high activity groups (score > 5.1). RESULTS: This study included 60 eyes of 30 RA patients. They scored a mean age of (44 ± 10 years), number of swollen joints (3 ± 3), number of tender joints (5 ± 3), duration of disease (8 ± 4), activity of the disease measured by DAS-28 (4.4 ± 0.9), and sex (males were 9.7% vs females 90.3%). The number of swollen joints, tender joints, ESR and DAS-28 were more in the high activity group with the p-value of (0.018, 0.001, < 0.003 and < 0.004), respectively. There are no statistically significant differences between both groups as regards disease duration (p-value of 3.8). The high activity group showed significant affection regarding the mebioscore of the lower and upper lids, total mebioscore, percentage of meibomian glands in upper and lower lids, first non-invasive break-up time test (NIV-BUT) of the tear film, as well as average non-invasive break-up time test (NIavg-BUT). There were moderate correlations between the activity of the disease represented by (DAS-28) and different parameters evaluating eye dryness (meiboscore of the lower and upper lids, total meiboscore, percentage of meibomian glands in upper and lower lids, NIV-BUT of the tear film, and NIavg-BUT of the tear film). CONCLUSION: There was no correlation with duration of RA but moderate correlations between the activity of the disease represented by (DAS-28) and different parameters evaluating eye dryness in RA patients with valuable use of noncontact Meibography to evaluate eye dryness in RA cases. Both Meiboscore and Meiboscale of Non-contact Meibography were found to be useful tools in grading of dry eye disease in different activity grades of Rheumatoid Arthritis.

A Deep Learning Approach for Meibomian Gland Appearance Evaluation.

Purpose: To develop and evaluate a deep learning algorithm for Meibomian gland characteristics calculation. Design: Evaluation of diagnostic technology. Subjects: A total of 1616 meibography images of both the upper (697) and lower (919) eyelids from a total of 282 individuals. Methods: Images were collected using the LipiView II device. All the provided data were split into 3 sets: the training, validation, and test sets. Data partitions used proportions of 70/10/20% and included data from 2 optometry settings. Each set was separately partitioned with these proportions, resulting in a balanced distribution of data from both settings. The images were divided based on patient identifiers, such that all images collected for one participant could end up only in one set. The labeled images were used to train a deep learning model, which was subsequently used for Meibomian gland segmentation. The model was then applied to calculate individual Meibomian gland metrics. Interreader agreement and agreement between manual and automated methods for Meibomian gland segmentation were also carried out to assess the accuracy of the automated approach. Main Outcome Measures: Meibomian gland metrics, including length ratio, area, tortuosity, intensity, and width, were measured. Additionally, the performance of the automated algorithms was evaluated using the aggregated Jaccard index. Results: The proposed semantic segmentation-based approach achieved average aggregated Jaccard index of mean 0.4718 (95% confidence interval [CI], 0.4680-0.4771) for the 'gland' class and a mean of 0.8470 (95% CI, 0.8432-0.8508) for the 'eyelid' class. The result for object detection-based approach was a mean of 0.4476 (95% CI, 0.4426-0.4533). Both artificial intelligence-based algorithms underestimated area, length ratio, tortuosity, widthmean, widthmedian, width10th, and width90th. Meibomian gland intensity was overestimated by both algorithms compared with the manual approach. The object detection-based algorithm seems to be as reliable as the manual approach only for Meibomian gland width10th calculation. Conclusions: The proposed approach can successfully segment Meibomian glands; however, to overcome problems with gland overlap and lack of image sharpness, the proposed method requires further development. The study presents another approach to utilizing automated, artificial intelligence-based methods in Meibomian gland health assessment that may assist clinicians in the diagnosis, treatment, and management of Meibomian gland dysfunction. Financial Disclosures: The authors have no proprietary or commercial interest in any materials discussed in this article.

Evaluation of Meibomian gland structure and appearance after therapeutic Meibomian gland expression.

CLINICAL RELEVANCE: Evaluating how Meibomian glands can change in appearance has the potential to advance the understanding of Meibomian gland health and may lead to enhanced diagnosis and therapy. BACKGROUND: This work aimed to investigate Meibomian gland appearance after therapeutic Meibomian gland expression. METHODS: Fifteen subjects attended three study visits over a two-week period. Meibography was performed before and after therapeutic Meibomian gland expression, the following day, and 2 weeks after expression. Six central glands were used to calculate Meibomian gland morphological parameters such as gland length ratio, gland width, gland area, gland tortuosity, and gland contrast. A custom semi-automated image analysis software was used to calculate Meibomian gland metrics. Furthermore, a high-resolution imaging system was developed to capture clear images of the Meibomian glands, free of any artefacts, which were used for precise calculations of Meibomian gland contrast. RESULTS: The expression procedure had a significant impact on Meibomian gland contrast and length ratio immediately afterwards. The least square mean difference (95% CI) from baseline for Michelson contrast was -0.006 (-0.010, -0.001) and -1.048 (-2.063, -0.033) for simple contrast. The least square mean ratio of the gland length ratio immediately after the expression to baseline was 0.758 (0.618, 0.931). CONCLUSIONS: Following therapeutic expression, Meibomian glands exhibit reduced brightness and length. However, within 24 h, they appear to recover and return to their baseline state, indicating a relatively short recovery time. This sheds light on whether meibography is solely focused on capturing gland structure or if it also captures acinar activity. The hyperreflective properties of lipids suggest that the decrease in contrast observed after expression could be attributed to a reduction in the visualisation of acini activity. A decrease in Meibomian gland length ratio implies that the loss of gland structure following treatment may be indicative of a temporary structural alteration.

Morphologic variants of Meibomian glands: age-wise distribution and differences between upper and lower eyelids.

Purpose: To evaluate the distribution of various Meibomian gland morphologies across different age groups in healthy individuals. Methods: The infrared meibographic morphologies of the Meibomian glands from the upper and lower eyelids of 236 healthy individuals (472 eyes; mean age 38.4 ± 17.5 years; 80 female participants: 156 male participants) were evaluated for their prevalence and differences across six decades of life, from 10 to 80 years. A linear mixed-effects modeling test was performed for statistical analysis. Results: Of 14,452 glands, 8,830 (61%) glands were located in the upper eyelid. No significant differences in frequency were noted between different age groups for distorted, tortuous, hooked, overlapping, abnormal gap, fluffy areas, dropout (except for 51-60 vs. 10-20 years, P = 0.023), and thick and thin morphologies. Short glands were significantly more common in individuals aged over 30 years (P = 0.015), whereas moderately short and severely short glands were more common in the upper eyelids of individuals older than 50 years compared to those aged 10-20 years (P = 0.035). The frequency of distorted, hooked, tortuous, overlapping, and tadpole-shaped Meibomian glands was significantly higher in the upper eyelids than in the lower eyelids for all age groups. Dropout glands were more common in the lower eyelids of individuals younger than 50 years, but no difference was observed in the upper and lower eyelids of individuals over 50 years. Dropout (P = 0.006) and severely short glands (0.026) of the lower eyelid were associated with low non-invasive tear break-up time (NIBUT) values. Conclusion: Various morphologic characteristics of the Meibomian glands that are considered abnormal can be present in healthy individuals, and only moderate to severely short glands display an increase in abnormal morphologic characteristics of the Meibomian glands with age.

Evaluation of dry eye and meibomian gland function in pregnancy.

PURPOSE: To evaluate the signs and symptoms of dry eye in healthy pregnant women and investigate the effect of pregnancy on meibomian gland loss using non-contact meibography. METHODS: Healthy pregnant women and age-matched healthy non-pregnant women were included in the study. Subjective symptoms were assessed using the Ocular Surface Disease Index (OSDI). The first and average non-invasive break-up times (first-NIBUT and avg-NIBUT, respectively) were determined, and the Schirmer test was applied. Non-contact meibography was performed. RESULTS: The study included a total of 62 women, 30 pregnant (study group) and 32 non-pregnant (control group). There was no significant difference between the groups in terms of OSDI score and the Schirmer test (p > 0.05). The mean first-NIBUT and avg-NIBUT values of the study group (13.1 ± 5.3 and 13.7 ± 4.5 s) were significantly lower than the control group (16.0 ± 2.4 and 16.4 ± 1.5 s) (p: 0.015 and p: 0.040, respectively). The mean meibomian gland losses in the upper and lower eyelids were significantly higher in the study group (16.9 ± 8.2% and 11.6 ± 10.2%) compared to the control group (9.7 ± 6.2% and 5.6 ± 4.7%) (p < 0.001 and p: 0.011, respectively). CONCLUSIONS: It is considered that loss of the meibomian glands may occur during pregnancy, and this may predispose pregnant women to evaporative dry eye. Although dry eye does not cause significant ocular surface symptoms in pregnancy, NIBUT and non-contact meibography can be considered as effective diagnostic methods for the detection of dry eye in pregnant women.

Impacts of gender and age on meibomian gland in aged people using artificial intelligence.

Purpose: To evaluate the effects of age and gender on meibomian gland (MG) parameters and the associations among MG parameters in aged people using a deep-learning based artificial intelligence (AI). Methods: A total of 119 subjects aged ≥60 were enrolled. Subjects completed an ocular surface disease index (OSDI) questionnaire, received ocular surface examinations including Meibography images captured by Keratograph 5M, diagnosis of meibomian gland dysfunction (MGD) and assessment of lid margin and meibum. Images were analyzed using an AI system to evaluate the MG area, density, number, height, width and tortuosity. Results: The mean age of the subjects was 71.61 ± 7.36 years. The prevalence of severe MGD and meibomian gland loss (MGL) increased with age, as well as the lid margin abnormities. Gender differences of MG morphological parameters were most significant in subjects less than 70 years old. The MG morphological parameters detected by AI system had strong relationship with the traditional manual evaluation of MGL and lid margin parameters. Lid margin abnormities were significantly correlated with MG height and MGL. OSDI was related to MGL, MG area, MG height, plugging and lipid extrusion test (LET). Male subjects, especially the ones who smoke or drink, had severe lid margin abnormities, and significantly decreased MG number, height, and area than the females. Conclusion: The AI system is a reliable and high-efficient method for evaluating MG morphology and function. MG morphological abnormities developed with age and were worse in the aging males, and smoking and drinking were risk factors.

The Effect of Oral Isotretinoin Therapy on Meibomian Gland Characteristics in Patients with Acne Vulgaris.

INTRODUCTION: The aim of the study was to determine the effect of oral isotretinoin therapy on the functional and morphological condition of the anterior segment of the eye, with particular emphasis on the meibomian glands. METHODS: Twenty-four patients (48 eyes) with a diagnosis of acne vulgaris were involved in the survey. All patients underwent a thorough ophthalmological examination at three time points: before therapy, 3 months after the start of therapy, and 1 month after the completion of isotretinoin therapy. The physical examination included the following elements: blink rate, analysis of the lid margin abnormality score (LAS), tear film break-up time (TFBUT) and Schirmer's test, meibomian gland loss (MGL), and the evaluation of the meibum quality score (MQS) and meibum expressibility score (MES). Additionally, the total score of an ocular surface disease index (OSDI) questionnaire was analysed. RESULTS: In comparison with pretreatment values, significant increases in OSDI during and after the treatment (p = 0.003 and p = 0.004, respectively) were observed. Substantial deterioration during the treatment was observed for MGL (p < 0.0001), MQS (p < 0.001) and LAS (p < 0.0001), while an improvement in those parameters after isotretinoin cessation was observed (p = 0.006, p = 0.02 and p = 0.0003, respectively). The frequency of using artificial eye drops was positively associated with MGL during (Spearman's rank correlation coefficient (Rs) = + 0.31; p = 0.03) and after the cessation of the therapy (Rs = + 0.28; p = 0.04). Meibomian gland atrophy correlated significantly with MQS during (Rs = + 0.29; p = 0.04) and after treatment (Rs = + 0.38; p = 0.008). The decrease in TFBUT values correlated with increased LAS (Rs = - 0.31; p = 0.03) during the course of isotretinoin usage. We found no changes in Schirmer's test or blink rates. CONCLUSION: Isotretinoin therapy leads to increased ocular complaints related to lipid tear film component dysfunction. This is due to reversible changes in meibomian gland morphology and function observed during drug usage.

Association of meibomian gland morphology with orifice plugging and lid margin thickening in meibomian gland dysfunction patients.

PURPOSE: We sought to investigate the association of meibomian gland morphology with lid margin abnormalities in patients with meibomian gland dysfunction. METHODS: This retrospective study included 368 eyes of 184 patients. Meibography was used to evaluate meibomian gland (MG) morphological features, such as dropout, distortion, thickened ratio and thinned ratio. Lid margin photography was used to evaluate lid margin abnormalities including orifice plugging, vascularity, irregularity and thickening. The association between MG morphological features and lid margin abnormalities was analyzed using a mixed linear model. RESULTS: The study found a positive correlation between plugging of gland orifices grade and MG dropout grade in both the upper lids (B = 0.40, p = 0.007) and the lower lids (B = 0.55, p = 0.001). Plugging of gland orifices grade was also positively correlated to MG distortion grade in the upper lids (B = 0.75, p = 0.006). In the upper lids, MG thickened ratio increased first (B = 0.21, p = 0.003) and then decreased (B = - 0.14, p = 0.010) with a higher lid margin thickening grade. MG thinned ratio was negatively correlated with lid margin thickening (B = - 0.14, p = 0.002, B = - 0.13, p = 0.007). MG distortion grade decreased with lid margin thickening (B = - 0.61, p = 0.012). CONCLUSION: Orifice plugging was correlated to meibomian gland distortion and dropout. Lid margin thickening was associated with meibomian gland thickened ratio, thinned ratio, and distortion. The study also suggested that distorted and thinned glands may be transitional phases between thickened glands and glands dropout.

Morphological and functional assessment of the tear film and meibomian glands in keratoconus.

PURPOSE: To evaluate morphological and functional state of the meibomian glands (MG) in keratoconus patients. METHODS: One hundred eyes of 100 keratoconus patients and 100 eyes of 100 age-matched control subjects were included into this study. Ocular Surface Disease Index (OSDI) scores, non-invasive break up time (NIBUT), findings of meibography, staining with fluorescein of the ocular surface, tear film break-up time (TBUT), and Schirmer I test were documented in all patients' eyes and control eyes and were compared between the groups . RESULTS: The mean TBUT and NIBUT were significantly lower, corneal staining and OSDI scores were statistically greater in the keratoconus group (p < 0.05). The mean meiboscore, partial gland, gland dropout and gland thickening scores for upper/lower eyelids were significantly greater in keratoconus patients than controls (p < 0.05). The NIBUT measurements significantly correlated with MG loss in upper/lower eyelids (p < 0.05). The severity of keratoconus seemed to correlate with meiboscore, partial gland, gland thickening scores in upper/lower eyelids. CONCLUSION: Our data suggests that corneal ectasia in keratoconus is related with alterations in ocular surface, tear film function and MG morphology. Early screening and treatment of MG dysfunction may improve ocular surface quality and allow better disease management in keratoconus patients.

Role of instrumental factors in Meibomian gland contrast assessment.

PURPOSE: Meibomian gland contrast has been suggested as a potential biomarker in Meibomian gland dysfunction. This study analysed the instrumental factors related to contrast. The objectives were to determine whether the mathematical equations used to compute gland contrast (e.g., Michelson or Yeh and Lin), impact the ability to identify abnormal individuals, to ascertain whether contrast between the gland and the background could be an effective biomarker and to assess whether using contrast-enhancement on the gland image improves its diagnostic efficacy. METHODS: A total of 240 meibography images from 40 participants (20 controls and 20 having Meibomian gland dysfunction or blepharitis), were included. The Oculus Keratograph 5M was used to capture images from the upper and lower eyelids of each eye. The contrast of unprocessed images and those pre-processed with contrast-enhancement algorithms were analysed. Contrast was measured on the eight central glands. Two equations for contrast computation were used, and the contrast both between glands and within a gland were calculated. RESULTS: Significant differences were found between the groups for inter-gland area in the upper (p = 0.01) and lower eyelids (p = 0.001) for contrast measured with the Michelson formula. Similar effects were observed when using the Yeh and Lin method in the upper (p = 0.01) and lower eyelids (p = 0.04). These results were obtained for images enhanced with the Keratograph 5M algorithm. CONCLUSIONS: Meibomian gland contrast is a useful biomarker of disease related to the Meibomian glands. Contrast measurement should be determined using contrast-enhanced images in the inter-gland area. However, the method used to compute contrast did not influence the results.