Application of a Novel Interferometric Method to Investigate the Relation between Lipid Layer Thickness and Tear Film Thinning

King‐Smith, P. Ewen; Hinel, Erich A.; Nichols, Jason J.

doi:10.1167/iovs.09-4387

Cited by 162 publications

(133 citation statements)

References 21 publications

(19 reference statements)

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“…The quality of the lipid layer controls the tear film evaporation. 34 The tangential flow and redistribution of the lipid layer may contribute to the small thickness variation over time as shown in Fig. 7(a).…”

Section: Measurements On a Human Eye With A Contact Lensmentioning

confidence: 99%

Tear film measurement by optical reflectometry technique

Wang

et al. 2014

J. Biomed. Opt

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Abstract. Evaluation of tear film is performed by an optical reflectometer system with alignment guided by a galvanometer scanner. The reflectometer system utilizes optical fibers to deliver illumination light to the tear film and collect the film reflectance as a function of wavelength. Film thickness is determined by best fitting the reflectance-wavelength curve. The spectral reflectance acquisition time is 15 ms, fast enough for detecting film thickness changes. Fast beam alignment of 1 s is achieved by the galvanometer scanner. The reflectometer was first used to evaluate artificial tear film on a model eye with and without a contact lens. The film thickness and thinning rate have been successfully quantified with the minimum measured thickness of about 0.3 μm. Tear films in human eyes, with and without a contact lens, have also been evaluated. A high-contrast spectral reflectance signal from the precontact lens tear film is clearly observed, and the thinning dynamics have been easily recorded from 3.69 to 1.31 μm with lipid layer thickness variation in the range of 41 to 67 nm. The accuracy of the measurement is better than AE0.58% of the film thickness at an estimated tear film refractive index error of AE0.001. The fiber-based reflectometer system is compact and easy to handle.

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Section: Measurements On a Human Eye With A Contact Lensmentioning

confidence: 99%

Tear film measurement by optical reflectometry technique

Wang

et al. 2014

J. Biomed. Opt

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“…Details of the eye alignment system are given by Nichols et al 26 evaporation rates. [35][36][37] Patients with dry eye and meibomian gland dysfunction have increased rates of evaporation due to alterations in lipid layer thickness and composition. 2,5,14,[38][39][40][41][42] It is hypothesized that evaporation and tangential flow are the most plausible mechanisms of tear film thinning under normal conditions.…”

mentioning

confidence: 99%

The Use of Fluorescent Quenching in Studying the Contribution of Evaporation to Tear Thinning

Nichols

King‐Smith

Hinel

et al. 2012

Invest. Ophthalmol. Vis. Sci.

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116

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PURPOSE. The purpose of our study was to test the prediction that if the tear film thins due to evaporation, rather than tangential flow, a high concentration of fluorescein in the tear film would show a greater reduction in fluorescent intensity compared to a low concentration of fluorescein due to selfquenching at high concentrations.METHODS. Tear film thickness, thinning rate, and fluorescent intensity were measured continuously and simultaneously with a modified spectral interferometer in 30 healthy subjects with two different concentrations (2% followed by 10%) of 1 lL of liquid fluorescein on the eye. Measurements of fluorescein selfquenching (fluorescent efficiency as a function of fluorescein concentration) are described in an Appendix and are reported in arbitrary units. RESULTS.Under low and high fluorescein concentration conditions, there were no differences in tear film thickness (P ¼ 0.09) or thinning rates (P ¼ 0.76). While the mean initial fluorescent intensity was similar between groups (637.47 6 381.47 vs. 672.09 6 649.72, P ¼ 0.55), the mean rate of fluorescent decay was 4-fold faster in the high (16.57 6 29.34) than in the low (4.11 6 6.78) concentration group (P < 0.01).CONCLUSIONS. The large difference in the rate of fluorescent decay between groups can be explained by the effects of evaporation and self quenching of fluorescein; the latter is expected to be greater for high than for low fluorescein concentration. Fluorescence decay due to tangential flow would be expected to be similar at high and low fluorescein concentrations. This supports previous evidence that evaporation has the primary role in normal tear thinning between blinks. (Invest Ophthalmol Vis Sci. 2012;53:5426-5432)

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“…We combined evaluation of the interferometric fringe with measurement of NIBUT to classify interferometric kinetics into three patterns. The tear interferometric fringe pattern was previously related to the severity of dry eye, 11 whereas tear dynamics visualized by interferometry were related to the volume of the aqueous layer of the tear film, 15,23 suggesting that the interferometric fringe pattern indicates the condition of both the lipid and aqueous layers. Given that our classification is based not only on the interferometric fringe pattern but also on tear film stability, it potentially reflects the relation between tear dynamics and the condition of the lipid layer.…”

Section: Discussionmentioning

confidence: 95%

“…5,11,17,[19][20][21] We have now evaluated the overall aqueous and lipid kinetics of the tear film, as well as measured the thickness of the lipid layer by tear interferometry, revealing the balance between the lipid and aqueous layers of the tear film, 11,15,22,23 in individuals with dry eye disease. Our results indicate that the interferometric color and fringe patterns associated with tear film stability reflect the balance between the aqueous and lipid layers of the tear film, and they suggest that these patterns are able to identify subtypes of dry eye.…”

Section: Discussionmentioning

confidence: 99%

“…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. We found that many cases categorized as interferometric pattern 1 showed an increased LLT, reduced tear secretion, and shortened NIBUT.…”

Section: Discussionmentioning

confidence: 99%

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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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Application of a Novel Interferometric Method to Investigate the Relation between Lipid Layer Thickness and Tear Film Thinning

Cited by 162 publications

References 21 publications

Tear film measurement by optical reflectometry technique

Tear film measurement by optical reflectometry technique

The Use of Fluorescent Quenching in Studying the Contribution of Evaporation to Tear Thinning

Tear Interferometric Patterns Reflect Clinical Tear Dynamics in Dry Eye Patients

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