Diurnal Pattern of Tear Osmolarity and Its Relationship to Corneal Thickness and Deswelling

Niimi, Joycelyn; Tan, Bo; Chang, Jenny; Zhou, Yuquan; Ghanekar, Avanti; Wong, Michelle; Lee, Annie; Lin, Meng C.

doi:10.1097/ico.0b013e31829b21d1

Cited by 45 publications

(60 citation statements)

References 19 publications

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“…Historical meta-analyses of tear osmolarity using laboratory-based freezing point osmometers report specificities of upward of 94% for the marker as a whole 15. In normal subjects with a healthy lacrimal system, repeated testing has been shown to have little to no effect on the measured tear osmolarity 12,28. Insofar that the recruited subjects are truly devoid of dry eye disease, an accurate osmometer is expected to report the majority of test results below the established cutoff for dry eye disease.…”

Section: Discussionmentioning

confidence: 99%

Randomized comparison of in vivo performance of two point-of-care tear film osmometers

Nolfi¹,

Caffery²

2017

OPTH

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PurposeTo compare the in vivo precision of two commercially available point-of-care osmometers among normal subjects with no dry eye disease.MethodsTwenty healthy adults with healthy ocular surfaces were evaluated by licensed eye care practitioners. All subjects had low Ocular Surface Disease Index score (<5), normal tear breakup time (>10 seconds), and no evidence of corneal fluorescein staining. Five consecutive measurements of tear osmolarity were measured on each eye using each of the two osmometers: the TearLab Osmolarity System (TearLab) and the I-Med i-Pen (i-Pen), for a total of 200 measurements per device. Performance of the osmometers was determined by specificity, estimated by the percentage of osmolarity data at or below the clinical cutoff (308 mOsm/L) and precision, and represented by the standard deviation per subject. In addition, to assess analytical performance, on each day of patient testing, standardized osmolarity quality control solutions (338 mOsm/L) were tested on the TearLab per manufacturer instructions. i-Pen manufacturer instructions do not neither provide for, nor recommend quality control procedures.ResultsThe mean age of the 20 subjects was 27±8 years (range: 19–48 years, 16 females, four males). Over 2 months of testing, the TearLab reported analytical performance on quality control solutions of 335.8±4.2 mOsm/L with a coefficient of variation of 1.3%. In the subject cohort, 90.9% of TearLab measurements were in the normal range ≤308 mOsm/L. The i-Pen reported 37.5% of all measurements in the normal range. The average intra-subject osmolarity of the TearLab was 295.4±8.6 mOsm/L, which was significantly lower and less variable than the i-Pen, which reported an average of 319.4±20.3 mOsm/L (P<0.001). When the measurements were grouped by subject, the TearLab accurately identified 100% of subjects as normal while the i-Pen accurately identified only 15% of subjects as normal.ConclusionIn this randomized comparative study of two point-of-care osmometers among normal, healthy non-dry eye subjects, the TearLab Osmolarity System demonstrated accuracy, precision, and agreement with clinical interpretation in line with the manufacturer claims. The i-Pen lacked sufficient performance to delineate subjects with and without dry eye disease.

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Section: Discussionmentioning

confidence: 99%

Randomized comparison of in vivo performance of two point-of-care tear film osmometers

Nolfi¹,

Caffery²

2017

OPTH

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“…Evidence indicates that there is no ethnicity-related difference in the relationship between osmolarity and corneal thickness. 44 However, there is a clinically significant difference in CCT among different ethnic groups. For example, on average, African Americans have a thinner CCT when compared with whites.…”

Section: Corneamentioning

confidence: 99%

“…[45][46][47] Other studies have demonstrated that Asians have a thicker CCT than African Americans, but little-to-no difference when compared with a Hispanic or white populations. 44,48,49 Given these inherent ethnicity-related differences in CCT, it is imperative to determine the individual magnitude of change in CCT before and after an intervention (e.g., contact lens wear) to determine its safety and efficacy. In studies where corneal edema is used as a "safety" index (e.g., development of prototype contact lenses or assessment of contact lens oxygen-transmissibility effects on corneal thickness), simply comparing group means can be misleading because withinsubject variability and the range of magnitudes of individual changes in CCT from preintervention to postintervention are not taken into account.…”

Section: Corneamentioning

confidence: 99%

Accounting for Ethnicity-Related Differences in Ocular Surface Integrity as a Step Toward Understanding Contact Lens Discomfort

Chan

Svitova

Lin³

2017

Eye &Amp; Contact Lens: Science &Amp; Clinical Practice

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Contact lens discomfort is a common problem that can lead to unsuccessful or limited contact lens wear. Although many factors may contribute to contact lens discomfort, limited research has explored the influence of ethnicity-related differences in the anatomy and physiology of the ocular surface. Therefore, we performed a search of the literature in PubMed using key words related to “ocular surface” paired with the terms “race” and “ethnicity.” The goal of this review was to determine potential areas of research regarding ethnicity differences, particularly between Asian and non-Asian eyes, in ocular surface integrity to advance our understanding of contact lens discomfort.

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“…9 Furthermore, physiological diurnal fluctuations in tear osmolarity have been shown to correlate with changes in central corneal thickness (CCT) in human eyes, as quantified using high-resolution anterior segment optical coherence tomography (OCT). 10 Preliminary evidence also suggests that individuals with clinical signs and symptoms of DED have reduced corneal thickness 11 and endothelial cell changes, 12 although the potential effect of tear osmolarity per se was not considered in these studies.…”

Section: Introductionmentioning

confidence: 99%

Optical Coherence Tomography Reveals Changes to Corneal Reflectivity and Thickness in Individuals with Tear Hyperosmolarity

Deinema

Vingrys

Chinnery

et al. 2017

Trans. Vis. Sci. Tech.

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PurposeTo investigate whether tear hyperosmolarity, a feature of dry eye disease (DED), affects central corneal thickness (CCT), corneal light reflectivity, and/or tear film reflectivity.MethodsThis prospective, cross-sectional study involved 48 participants (38 with hyperosmolar tears and 10 controls with normo-osmolar tears). Symptoms and signs of DED (tear osmolarity, sodium fluorescein tear break-up time, ocular surface staining, Schirmer test) were assessed. CCT, and the reflectivity of the cornea and the tear-epithelial interface were quantified relative to background noise using Fourier-domain optical coherence tomography (FD-OCT).ResultsCCT of eyes with severe tear hyperosmolarity, defined as eyes in the upper quartile of the hyperosmolar group, was less than control eyes (539.1 ± 7.4 vs. 583.1 ± 15.0 μm, P = 0.02) and eyes with less severe tear hyperosmolarity, defined as hyperosmolar eyes in the lower quartile (622.7 ± 5.8 μm, P < 0.0001). CCT showed a negative linear relationship with tear osmolarity for values above 316 mOsmol/L (R2 = 0.17, P = 0.01). Central corneal reflectivity was lower in hyperosmolar eyes than normo-osmolar eyes (45.1 ± 0.3 vs. 48.1 ± 0.6 pixels, P = 0.02); the greatest relative difference was in the anterior stroma, where corneal reflectivity was 4.7 ± 1.9% less in hyperosmolar eyes (P < 0.01). Peak reflectivity of the tear-epithelial interface was 4.8% ± 3.5% higher in the hyperosmolar group than the normo-osmolar tear group (P = 0.04).ConclusionIndividuals with significant tear hyperosmolarity and clinical signs of symptoms of DED show reduced CCT and altered corneal reflectivity.Translational RelevanceAnterior segment FD-OCT provides novel insight into corneal microstructural differences in individuals with DED.

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Diurnal Pattern of Tear Osmolarity and Its Relationship to Corneal Thickness and Deswelling

Cited by 45 publications

References 19 publications

Randomized comparison of in vivo performance of two point-of-care tear film osmometers

Randomized comparison of in vivo performance of two point-of-care tear film osmometers

Accounting for Ethnicity-Related Differences in Ocular Surface Integrity as a Step Toward Understanding Contact Lens Discomfort

Optical Coherence Tomography Reveals Changes to Corneal Reflectivity and Thickness in Individuals with Tear Hyperosmolarity

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