The real reason for having a meibomian lipid layer covering the outer surface of the tear film – A review

Millar, Thomas J.; Schuett, Burkhardt S.

doi:10.1016/j.exer.2015.05.002

Cited by 111 publications

(79 citation statements)

References 120 publications

(194 reference statements)

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“…An increase in tear lipids or improvement in the composition of certain lipids would increase the barrier for tear evaporation of the aqueous tear or stability of the entire tearfilm, [23][24][25][26][27] as well as facilitate dynamic tear spreading between eyelid blinks. 28 In a previous paper, the patients who had symptomatic improvement also had an associated decrease in inflammatory lipids such as lysophospholipids. 23 Lid warming may have reduced retention time of lipids in the glands, thereby reducing generation of certain inflammatory lipids due to bacterial lipases or other enzymes.…”

Section: Discussionmentioning

confidence: 99%

Longitudinal Changes in Tear Evaporation Rates After Eyelid Warming Therapies in Meibomian Gland Dysfunction

Yeo

Tan

Acharya

et al. 2016

Invest. Ophthalmol. Vis. Sci.

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Citation: Yeo S, Tan JH, Acharya UR, Sudarshan VK, Tong L. Longitudinal changes in tear evaporation rates after eyelid warming therapies in meibomian gland dysfunction. Invest Ophthalmol Vis Sci. 2016;57:197457: -198157: . DOI:10.1167 PURPOSE. Lid warming is the major treatment for meibomian gland dysfunction (MGD). The purpose of the study was to determine the longitudinal changes of tear evaporation after lid warming in patients with MGD.METHODS. Ninety patients with MGD were enrolled from a dry eye clinic at Singapore National Eye Center in an interventional trial. Participants were treated with hot towel (n ¼ 22), EyeGiene (n ¼ 22), or Blephasteam (n ¼ 22) twice daily or a single 12-minute session of Lipiflow (n ¼ 24). Ocular surface infrared thermography was performed at baseline and 4 and 12 weeks after the treatment, and image features were extracted from the captured images.RESULTS. The baseline of conjunctival tear evaporation (TE) rate (n ¼ 90) was 66.1 6 21.1 W/ min. The rates were not significantly different between sexes, ages, symptom severities, tear breakup times, Schirmer test, corneal fluorescein staining, or treatment groups. Using a general linear model (repeat measures), the conjunctival TE rate was reduced with time after treatment. A higher baseline evaporation rate ( ‡66 W/min) was associated with greater reduction of evaporation rate after treatment. Seven of 10 thermography features at baseline were predictive of reduction in irritative symptoms after treatment.CONCLUSIONS. Conjunctival TE rates can be effectively reduced by lid warming treatment in some MGD patients. Individual baseline thermography image features can be predictive of the response to lid warming therapy. For patients that do not have excessive TE, additional therapy, for example, anti-inflammatory therapy, may be required. (ClinicalTrials.gov number, NCT01683318 and NCT01448369.)

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Section: Discussionmentioning

confidence: 99%

Longitudinal Changes in Tear Evaporation Rates After Eyelid Warming Therapies in Meibomian Gland Dysfunction

Yeo

Tan

Acharya

et al. 2016

Invest. Ophthalmol. Vis. Sci.

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“…Lipids supplied principally by the meibomian glands provide the tear film lipid layer (TFLL), a complex mixture of lipids that create a thin hydrophobic film that serves to protect the tear film from evaporation. The physical properties of the tear film such as its stability and spreading are greatly influenced by the molecular lipid composition of the TFLL [3][4][5][6] . Deviations in the composition of the TFLL are likely to modulate the physical properties of the tear film and in turn effect a change in evaporation of the aqueous tear 7 .…”

Section: Introductionmentioning

confidence: 99%

Intersubject and Interday Variability in Human Tear and Meibum Lipidomes: A Pilot Study

et al. 2016

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Mitchell, T. W. (2016). Intersubject and interday variability in human tear and meibum lipidomes: a pilot study. The Ocular Surface, 14 (1), 43-48. Intersubject and interday variability in human tear and meibum lipidomes: a pilot study Abstract Purpose Our aim was to quantitate day-to-day changes in the tear and meibum lipid profile of individual subjects in a pilot study of healthy humans. Methods Matched tear and meibum samples were obtained from four subjects on three consecutive days. Quantitative lipid profiles of human basal tears and meibum were compared using multivariate analysis by principal components. Results Substantial differences in the lipid profile between subjects were observed, while lipid profiles were steady across the three consecutive days of sampling. Multivariate principal component analysis demonstrated that lysophosphatidylcholine was the largest variant lipid class between subjects in tears, while wax esters comprised the most variation between subjects in meibum secretions. Conclusion Interday variability is shown to be much smaller than interpatient variability, suggesting that tears and meibum subjects both have unique profiles in humans. Disciplines Medicine and Health Sciences Publication DetailsBrown, S. H. J., Kunnen, C. M. E., Papas, E. B., Lazon de la Jara, P., Willcox, M. D. P., Blanksby, S. 2 ABSTRACT Purpose: Our aim was to quantitate day-to-day changes in the tear and meibum lipid profile of individual subjects in a pilot study of healthy humans.Methods: Matched tear and meibum samples were obtained from four subjects on three consecutive days. Quantitative lipid profiles of human basal tears and meibum were compared using multivariate analysis by principal components.Results: Substantial differences in the lipid profile between subjects were observed, while lipid profiles were steady across the three consecutive days of sampling.Multivariate principal component analysis demonstrated that lysophosphatidylcholine was the largest variant lipid class between subjects in tears, while wax ester contributed the most to variation between subjects in meibum secretions.Conclusion: Inter-day variability is shown to be much smaller that inter-patient variability, suggesting that both tears and meibum subjects have unique profiles in individuals.

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“…[3][4][5][6][7][8][9] The estimated amount of PLs in tears is on the order of 5 to 20 mol% of all lipids. 10 Despite their small proportion relative to nonpolar lipids, PLs seem to have an essential impact on the function of the TFLL and, consequently, on the health of the ocular surface. 11 Cholesteryl esters and WEs are classified as nonpolar since they lack the large highly hydrophilic head group of polar lipids.…”

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confidence: 99%

The Effect of Phospholipids on Tear Film Lipid Layer Surface Activity

Rantamäki

Holopainen

2017

Invest. Ophthalmol. Vis. Sci.

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Citation: Rantamäki AH, Holopainen JM. The effect of phospholipids on tear film lipid layer surface activity. Invest Ophthalmol Vis Sci. 2017;58:149-154. DOI:10.1167/ iovs.16-20468 PURPOSE. We illustrate the importance of small quantities (<10 mol%) of polar phospholipids on the surface-active behavior of meibum-like lipid compositions.METHODS. Artificial meibum-like lipid mixture containing cholesteryl and wax esters was mixed with differing amounts of phosphatidylcholine (PC). The surface activity of these mixtures was investigated at the air-water interface by recording surface pressure created by the lipid layer as a function of molecular area at 378C. The PC proportion in the mixtures was 0, 2.5, 5, 7.5, or 10 mol%, and the remaining proportion in the mixture was 50:50 (mol/mol) of cholesteryl oleate (CO) and behenyl oleate (BO). Also, the effect of temperature was investigated.RESULTS. The surface activity of the mixtures increased in a very predictable and consistent fashion as a function of the PC proportion. The lipid mixture containing only CO and BO showed miniscule surface activity. However, already 2.5% PC mixed with the nonpolar CO and BO generated considerable increase in surface pressure. At small surface areas, the behavior of 7.5% and 10% PC compositions started to approach that of a pure PC monolayer. The temperature did not have a considerable impact on the surface-active behavior of the PCcontaining compositions.CONCLUSIONS. The polar phospholipids have a considerable effect on the surface-active properties of artificial tear film lipid layer (TFLL) compositions. Surprisingly, this takes place already at very low and physiologically relevant PC proportions. The effect is more dependent on the actual amount of the phospholipids at the air-tear interface than on the relative amount of these lipids in TFLL.

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The real reason for having a meibomian lipid layer covering the outer surface of the tear film – A review

Cited by 111 publications

References 120 publications

Longitudinal Changes in Tear Evaporation Rates After Eyelid Warming Therapies in Meibomian Gland Dysfunction

Longitudinal Changes in Tear Evaporation Rates After Eyelid Warming Therapies in Meibomian Gland Dysfunction

Intersubject and Interday Variability in Human Tear and Meibum Lipidomes: A Pilot Study

The Effect of Phospholipids on Tear Film Lipid Layer Surface Activity

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