Comparison of subjective grading of lid wiper epitheliopathy with a semi-objective method

Purpose: To validate a semi-objective method of grading lid wiper epitheliopathy (LWE) compared to subjective assessment. Methods: Twenty upper and 20 lower eyelid margins of patients with LWE were photographed after instillation of fluorescein and lissamine green. The images were graded by two observers using a 0-3 grading scale for height (%) and width (mm) of the lid staining. The images were also processed using custom designed software in MATLAB. After manual delineation of the staining area, width and perpendicular height were automatically measured throughout the selected area. The height as a proportion of the lid margin width and width measures were then categorized into the same bins as in the grading scale. Results: Repeatability of the image analysis system showed a mean difference (95% limits of agreement) between repeats of -0.01mm (0.03 and -0.05mm) for LWE height, 0.04mm (1.16 and -1.08mm) for LWE width, and -0.11mm2 (0.32 and -0.53mm2) for LWE area. The mean difference (95% limits of agreement) between image analysis and human grading for LWE height was -0.84 grades (0.54 and -2.21 grades), for LWE width was 0.31 grades (1.22 and -0.59 grades), and for the final grade (mean height and width) was -0.26 (0.44 and -0.96 grades) (all p <0.001). Conclusion: Human observers tend to overestimate the height and underestimate the width of LWE staining. Lid wiper region is not well defined, thus, it might be a difficult process for human observers to judge the stained region as a proportion of the lid wiper total region

The influence of Meibomian gland morphology and function on ocular comfort

Dry eye is a highly prevalent disease causing symptoms of discomfort that are severe and disabling for many sufferers. One of the leading causes of the evaporative form of this complaint is believed to be Meibomian Gland Dysfunction (MGD). Although clinical manifestations of MGD are easily observed, the association between the morphology and function of the meibomian gland and the symptoms experienced by those affected, remains controversial. Better understanding of this relationship may help to predict those at risk and will contribute to development of effective treatments and preventative strategies.This thesis describes a series of studies designed to investigate the relationship between subjective ocular symptomatology and both meibomian gland morphology and function.Grading scales commonly used to assess meibomian gland morphology and lid wiper epitheliopathy were validated and found to offer only moderate sensitivity to detect changes. Objective assessment systems incorporating image analysis software were developed which permitted highly repeatable and accurate assessment of meibomian gland morphology and lid wiper epitheliopathy.The Korb meibomian gland evaluator and the meibomian gland forceps were identified as the optimal meibum expression methods.Tears and meibum were collected and analysed using nano-electrospray, mass spectrometry. These techniques were able to identify and quantify the major classes of component lipids. The lipid profiles derived showed good repeatability, both within and between days. A comparison between tears and meibum showed them to have similar lipid profiles, apart from phospholipids, which occurred roughly four orders of magnitude more abundantly in tears. This confirmed that meibum is not the major source of phospholipids in tears.No clear relationship between meibomian gland morphology and symptoms of discomfort was found, with the possible exception that meibomian gland coverage of the upper lid is reduced in those with more severe symptoms.For meibomian gland function, weak to moderate associations between ocular symptomatology and the position of Marx’s line and the frequency of eye rubbing were observed. Meibum quality and the relative proportion of (O-acyl)-omega-hydroxy fatty acid (OAHFA) in tears were found to potentially discriminate those with the most severe symptoms from the rest of the sample

Revue finance, contrôle, stratégie : FCS

The aim of this study was to evaluate a human meibomian gland epithelial cell line (HMGEC) as a model for meibomian gland (patho)physiology in vitro.HMGEC were cultured in the absence or presence of serum. Sudan III lipid staining, ultrastructural analysis and lipidomic analyses were performed. Impedance sensing, desmoplakin 1/2 mRNA and cytokeratin (CK) 1, 5, 6, 14 levels were evaluated. Serum containing medium supplemented with higher serum, glucose, an omega-3 lipid cocktail, eicosapentaenoic acid or sebomed medium were investigated for lipid accumulation and ultrastructural morphology.Lipid droplet accumulation in HMGEC was induced by serum containing media after 1 day, but decreased over time. Cultivation in serum induced desmosome and cytokeratin filament formation. Desmoplakin 1/2 gene levels were significantly upregulated after 1d of serum treatment. Furthermore, the normalized impedance increased significantly. Lipidome analysis revealed high levels of phospholipids (over 50%), but very low levels of wax ester and cholesteryl esters (under 1%). Stimulation with eicosapentaenoic acid increased lipid accumulation after one day.Serum treatment of HMGEC caused lipid droplet formation to some extent but also induced keratinization. The cells did not produce typical meibum lipids under these growth conditions. HMGEC are well suited to study (hyper)keratinization processes of meibomian gland epithelial cells in vitro

A comparison of patient matched meibum and tear lipidomes

Purpose - To quantify the molecular lipid composition of patient-matched tear and meibum samples and compare tear and meibum lipid molecular profiles. Methods - Lipids were extracted from tears and meibum by bi-phasic methods using 10:3 tertbutyl methyl ether:methanol, washed with aqueous ammonium acetate, and analyzed by chipbased nanoelectrospray ionization tandem mass spectrometry. Targeted precursor ion and neutral loss scans identified individual molecular lipids and quantification was obtained by comparison to internal standards in each lipid class. Results - Two hundred and thirty-six lipid species were identified and quantified from nine lipid classes comprised of cholesterol esters, wax esters, (O-acyl)-x-hydroxy fatty acids, triacylglycerols, phosphatidylcholine, lysophosphatidylcholine, phosphatidylethanolamine, sphingomyelin, and phosphatidylserine. With the exception of phospholipids, lipid molecular profiles were strikingly similar between tears and meibum. Conclusions - Comparisons between tears and meibum indicate that meibum is likely to supply the majority of lipids in the tear film lipid layer. However, the observed higher mole ratio of phospholipid in tears shows that analysis of meibum alone does not provide a complete understanding of the tear film lipid composition

Nervnaja sistema : mezvuzovskij sbornik

Purpose To compare the lipid composition of human meibum across three different meibum expression techniques. Methods Meibum was collected from five healthy non-contact lens wearers (aged 20-35 years) after cleaning the eyelid margin using three meibum expression methods: cotton buds (CB), meibomian gland evaluator (MGE) and meibomian gland forceps (MGF). Meibum was also collected using cotton buds without cleaning the eyelid margin (CBn). Lipids were analyzed by chip-based, nano-electrospray mass spectrometry (ESI-MS). Comparisons were made using linear mixed models. Results Tandem MS enabled identification and quantification of over 200 lipid species across ten lipid classes. There were significant differences between collection techniques in the relative quantities of polar lipids obtained (P<.05). The MGE method returned smaller polar lipid quantities than the CB approaches. No significant differences were found between techniques for nonpolar lipids. No significant differences were found between cleaned and non-cleaned eyelids for polar or nonpolar lipids. Conclusion Meibum expression technique influences the relative amount of phospholipids in the resulting sample. The highest amounts of phospholipids were detected with the CB approaches and the lowest with the MGE technique. Cleaning the eyelid margin prior to expression was not found to affect the lipid composition of the sample. This may be a consequence of the more forceful expression resulting in cell membrane contamination or higher risk of tear lipid contamination as a result of reflex tearing.© 2016 Elsevier Inc