Tear Film Breakup and Structure Studied by Simultaneous Video Recording of Fluorescence and Tear Film Lipid Layer Images

King‐Smith, P. Ewen; Reuter, Kathleen; Braun, Richard; Nichols, Jason J.; Nichols, Kelly K.

doi:10.1167/iovs.13-11878

Cited by 91 publications

(103 citation statements)

References 28 publications

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“…What is assessed in this section is the scientific evidence for the TFLL being responsible for this evaporative resistance. It is commonly believed that the TFLL forms a blanket that prevents evaporation (Lemp et al, 2007;Nichols et al, 2011;King-Smith et al, 2013b), and that a cause of dry eye syndrome is due to increased evaporation because the lipid layer is "broken". This strong belief is not supported by the evidence in the literature.…”

Section: Prevention Of Evaporationmentioning

confidence: 99%

“…The formation of such lenses may be critical for allowing the spread of the lipid layer following a blink. Rather than a simple balling-up/ condensation of the hydrophobic molecules as suggested by the in silico modelling of Kulovesi et al (2012), King-Smith et al (2013b) provided a novel and insightful concept of a folded lipid layer to explain how the lipid layer is able to spread, and take up the possibility of how the WEs and Ch-Es might align into different domains. Although this folding model incorporates some of the features of the liquid crystal model proposed by Millar (2013) and would also resist collapse of the tear film, it has a distinct advantage in that it incorporates a mechanism for spreading the lipid layer following a blink.…”

Section: Structural Characteristics Of the Tfllmentioning

confidence: 99%

“…The tear film lipid layer (TFLL) covering the surface of the tear film has been detected using interference methods (Goto andTseng, 2003a, 2003b;King-Smith et al, 2013a). Seven different functions were ascribed to the TFLL in a review by Table 4).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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

Millar

Schuett

2015

Experimental Eye Research

111

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Section: Prevention Of Evaporationmentioning

confidence: 99%

Section: Structural Characteristics Of the Tfllmentioning

confidence: 99%

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

Millar

Schuett

2015

Experimental Eye Research

111

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“…We found that the amount of lipid on the surface (estimated to be 0.7 to over 7 µm thick) did not affect R evap in agreement with in vivo studies (Section IV.B.1.). 22,56–60 Our results indicate that when a water molecule achieves sufficient energy to escape the surface, it escapes whether the interface is a layer of lipid or air. The water molecules find their way into the lipid layer and eventually make their way to escape as a gas into the air.…”

Section: Discussionmentioning

confidence: 76%

Evaporation and Hydrocarbon Chain Conformation of Surface Lipid Films

et al. 2016

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Purpose The inhibition of the rate of evaporation (Revap) by surface lipids is relevant to reservoirs and dry eye. Our aim was to test the idea that lipid surface films inhibit Revap. Methods Revap were determined gravimetrically. Hydrocarbon chain conformation and structure were measured using a Raman microscope. Six 1-hydroxyl hydrocarbons (11–24 carbons in length) and human meibum were studied. Reflex tears were obtained from a 62-year-old male. Results The Raman scattering intensity of the lipid film deviated by about 7 % for hydroxyl lipids and varied by 21 % for meibum films across the entire film at a resolution of 5 µm2. All of the surface lipids were ordered. Revap of the shorter chain hydroxyl lipids were slightly (7%) but significantly lower compared with the longer chain hydroxyl lipids. Revap of both groups was essentially similar to that of buffer. A hydroxyl lipid film did not influence Revap over an estimated average thickness range of 0.69 to >6.9 µm. Revap of human tears and buffer with and without human meibum (34.4 µm thick) was not significantly different. Revap of human tears was not significantly different from buffer. Conclusions Human meibum and hydroxyl lipids, regardless of their fluidity, chain length, or thickness did not inhibit Revap of buffer or tears even though they completely covered the surface. It is unlikely that hydroxyl lipids can be used to inhibit Revap of reservoirs. Our data do not support the widely accepted (yet unconfirmed) idea that the tear film lipid layer inhibits Revap of tears.

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“…36 Other studies showed that NIBUT or BUT, each of which reflects tear film stability, was not significantly correlated with LLT. 23,28,[37][38][39] In the present study, we measured both LLT and tear secretion as indicated by Schirmer's test.…”

Section: Discussionmentioning

confidence: 96%

Tear Interferometric Patterns Reflect Clinical Tear Dynamics in Dry Eye Patients

Arita

Morishige

Fujii

et al. 2016

Invest. Ophthalmol. Vis. Sci.

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PURPOSE. We investigated whether the tear interferometric pattern was able to identify differences in tear film kinetics among clinical subtypes of dry eye. METHODS.A total of 138 eyes of 76 subjects (38 men and 38 women; mean age 6 SD, 61.6 6 16.2 years) with or without dry eye who visited Itoh Clinic from May to August 2015 were enrolled in a cross-sectional study. Clinical diagnosis of dry eye subtype was based on tear film parameters. The pattern of tear film kinetics determined by interferometry was classified as 0 (monotonous gray or multicolor interferometric fringe with a noninvasive breakup time [NIBUT] of ‡5 seconds), 1 (multicolor interferometric fringe with a NIBUT of <5 seconds), or 2 (grayish amorphous interferometric fringe with a NIBUT of <5 seconds), and reliability of classification was evaluated. Lipid layer thickness (LLT) for the tear film was also determined by interferometry. RESULTS.Interrater j values for evaluation of interferometric patterns ranged from 0.57 to 0.94 for both physicians and nonphysicians with reference to a dry eye expert, the latter of whom showed an intrarater reliability of 0.90. The distribution of eyes among interferometric patterns 0, 1, and 2 coincided well with the clinical subgroups of normal tear condition, nonSjögren syndrome aqueous-deficient dry eye, and meibomian gland dysfunction, respectively. A multicolor interferometric fringe was essentially observed only at an LLT of >70 nm. CONCLUSIONS.Tear interferometry was able to reliably distinguish clinical subtypes of dry eye by reflecting the balance between the lipid and aqueous layers of the tear film.Keywords: tear interferometry, dry eye, meibomiangland T he tear film consists of aqueous, mucin, and lipid layers with different levels of complexity.1 The quality and quantity of each layer, as well as their interactive relations, are important for homeostasis of the tear film. Impairment of the quality or changes in the quantity of tear film components can result in dry eye disease, which is categorized as either aqueous-deficient dry eye (ADDE) or evaporative dry eye (EDE).2,3 Dysfunction or hypofunction of lacrimal glands and the consequent reduced volume of the aqueous layer of the tear film thus underlie ADDE. Similarly, dysfunction or hypofunction of meibomian glands (which produce the lipid components of the tear film) or reduced production of mucin proteins by conjunctival goblet cells increases the evaporation of tear fluid and results in EDE.Interferometry has been applied as a noninvasive method for visualization of the lucent lipid layer at the surface of the tear film. 4 Tear interference images associated with surface phenomena of the tear film have thus been obtained 5-8 based on a principle first described by Newton. 9 This approach has been adopted to study tear dynamics in individuals with Sjögren syndrome 10 or dry eye, 11 including EDE, 12 as well as in contact lens wearers. 6,13 It has also been used to measure the thickness of the lipid layer of the tear film in normal subjects, 14 in...

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Tear Film Breakup and Structure Studied by Simultaneous Video Recording of Fluorescence and Tear Film Lipid Layer Images

Cited by 91 publications

References 28 publications

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

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

Evaporation and Hydrocarbon Chain Conformation of Surface Lipid Films

Tear Interferometric Patterns Reflect Clinical Tear Dynamics in Dry Eye Patients

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