The thickness of the tear film

King‐Smith, P. Ewen; Fink, Barbara A.; Hill, Richard M.; Koelling, Kurt W.; Tiffany, John M.

doi:10.1080/02713680490516099

Cited by 259 publications

(210 citation statements)

References 36 publications

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“…It has been suggested that a thinner lipid layer in the superior cornea immediately after a blink causes a high surface tension, which results in upward drift of the tear film and then leads to a thicker tear film in the upper cornea. 1,14 Owens and Phillips 15 found that tear upward spreading velocity decreased to minimum one s post-blink. Our results also showed that the increase in ocular surface height in the superior region of the map in the 'build-up phase' was first very rapid (less than 1 s) and then became relatively stable.…”

Section: Discussionmentioning

confidence: 99%

Dynamics of ocular surface topography

Zhu

Collins

Iskander

2006

Eye

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Purpose To investigate fluctuations in the ocular surface, we used high-speed videokeratoscopy (50 Hz) to measure the dynamics of the ocular surface topography. Methods Ocular surface height difference maps were computed to illustrate the changes in the tear film in the inter-blink interval. Topography data were used to derive the ocular surface wavefront aberrations up to the fourth radial order of the Zernike polynomial expansion. We examined the ocular surface dynamics and temporal changes in the ocular surface wavefront aberrations in the inter-blink interval. Results During the first 0.5 s following a blink, the ocular surface height at the upper edge of the topography map increased by about 2 lm. Temporal changes occurred for some ocular surface wavefront aberrations and appeared to be related to changes in the distribution of tear film. Conclusion In the clinical measurement of ocular surface topography using videokeratoscopy or optics of the eye using wavefront sensors, care should be taken to avoid the initial tear film build-up phase following a blink to achieve more consistent results.

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Section: Discussionmentioning

confidence: 99%

Dynamics of ocular surface topography

Zhu

Collins

Iskander

2006

Eye

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“…Because the aqueous layer has the largest volume in the tear film, here we only consider the aqueous layer [11]; we take this as a first approximation, to be refined in future investigations. We model the tear film as a one layer structure with two interfaces, the interface of the air and the tear film and the interface of the tear film and the cornea; these are shown schematically in Fig.…”

Section: Tear Film Modelmentioning

confidence: 99%

Maximum-likelihood estimation in Optical Coherence Tomography in the context of the tear film dynamics

Huang¹,

Clarkson²,

Kupinski³

et al. 2013

Biomed. Opt. Express

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Understanding tear film dynamics is a prerequisite for advancing the management of Dry Eye Disease (DED). In this paper, we discuss the use of optical coherence tomography (OCT) and statistical decision theory to analyze the tear film dynamics of a digital phantom. We implement a maximum-likelihood (ML) estimator to interpret OCT data based on mathematical models of Fourier-Domain OCT and the tear film. With the methodology of task-based assessment, we quantify the tradeoffs among key imaging system parameters. We find, on the assumption that the broadband light source is characterized by circular Gaussian statistics, ML estimates of 40 nm +/− 4 nm for an axial resolution of 1 μm and an integration time of 5 μs. Finally, the estimator is validated with a digital phantom of tear film dynamics, which reveals estimates of nanometer precision. Ferris, "Task-based optimization and performance assessment in optical coherence imaging," J. Opt. Soc. Am. A 22(6), 1132-1142 (2005). 7. A. C. Akcay, E. Clarkson, and J. P. Rolland, "Effect of source spectral shape on task-based assessment of detection and resolution in optical coherence tomography," Appl. Opt. 44(35), 7573-7580 (2005). 8.

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“…Tear film (TF) is a complex lipid-protein mixture that forms 3 m thin layer over the entire (approximately 2 cm 2 ) ocular surface [1]. This large area-to-volume ratio determines the importance of the low surface tension at the air/tear interface for the overall TF stability [2,3].…”

Section: Introductionmentioning

confidence: 99%

Interactions of Meibomian gland secretion with polar lipids in Langmuir monolayers

Georgiev

Kutsarova

Jordanova

et al. 2010

Colloids and Surfaces B: Biointerfaces

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a b s t r a c tThe surface interactions of Meibomian gland secretion (MGS) with polar lipid (PL), Egg Sphingomyelin (SM) or Dipalmitoylphosphatidylcholine (DPPC), are studied in mixed pseudo-binary films formed at the air/water interface of Langmuir surface balance. The behavior of the mixed films during slow quasi-equilibrium compression and during fast dynamic compression-decompression is registered by measurements of surface pressure and surface potential, and by monitoring film morphology with Brewster Angle Microscopy (BAM). Quasi-equilibrium compression isotherms are used to calculate the excess Gibbs and Helmholtz energy of mixing between MGS and PLs and thus to evaluate the interactions between the lipid compounds at the interface. The effects of PLs on the mixed film's elastic moduli of area compressibility, morphology and capability to attain high surface pressures are also examined.PLs interact with MGS with different strength and in different manner: MGS-SM interaction is weak and might lead to interfacial disaggregation of the thick meibium domains when SM is in excess, while MGS-DPPC interaction is strong and results in the formation of thick lipid aggregates. Both PLs increase the mixed films reciprocal compressibility and capability to achieve higher surface pressures. The results demonstrate that in vitro studies of the surface interactions between MGS and PLs might be beneficial in the selection of PLs for artificial tear formulations and for examination on molecular scale of the possible role of PLs at the ocular surface.

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The thickness of the tear film

Cited by 259 publications

References 36 publications

Dynamics of ocular surface topography

Dynamics of ocular surface topography

Maximum-likelihood estimation in Optical Coherence Tomography in the context of the tear film dynamics

Interactions of Meibomian gland secretion with polar lipids in Langmuir monolayers

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