Diurnal variations in tear film break‐up time determined in healthy subjects by software‐assisted interpretation of tear film video recordings (original) (raw)
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Contact Lens and Anterior Eye, 2019
Purpose: Since tear film stability can be affected by fluorescein, the International Dry Eye Workshop (DEWSII) recommended non-invasive measurement of tear breakup time (NIBUT). The aim of this study was to investigate the agreement and repeatability of four different instruments in the measurement of NIBUT. Methods: 72 participants (mean 24.2 ± 3.6 years) were recruited for this multi-centre, cross-sectional study. NIBUT was measured three times from one eye using each of the instruments in randomized order on two separate sessions during a day, separated by at least 2 hours. NIBUT was performed at three sites (Switzerland, Germany and UK) using the Tearscope Plus (Keeler, Windsor, UK) (TS), Polaris (bon Optic, Lübeck, Germany) (POL), EasyTear Viewplus (Easytear, Rovereto, Italy) (ET) and Keratograph 5M (Oculus Optikgeräte GmbH, Wetzlar, Germany) (KER). As the latter instrument only analyses for 24s, all data was capped at this value. Results: NIBUT measurements between the four instruments were not statistically
Contact Lens and Anterior Eye, 2020
To evaluate the comparability, discriminative ability, and optimal thresholds for non-invasive tear film breakup time measurements obtained from the Oculus Keratograph 5M and Medmont E300 in detecting other signs and symptoms of dry eye disease, as defined by the TFOS DEWS II diagnostic criteria. Methods: One hundred and thirty-four participants (53 male, 81 female), with a mean ± SD age of 48 ± 20 years, were recruited into a prospective, investigator-masked, diagnostic accuracy study. Dry eye symptomology, tear film parameters (including non-invasive Keratograph and Medmont breakup time), and ocular surface staining were evaluated in a single clinical session. Results: Significant positive correlation was observed between the two automated instruments (p < 0.001), although non-invasive breakup time measurements obtained from the Medmont were significantly longer (p < 0.001), and demonstrated greater intra-subject and inter-subject variability (all p < 0.001). The areas under the ROC curves exceeded 0.65 for both instruments, and the discriminative abilities were comparable (p = 0.53). The Youden optimal diagnostic threshold for non-invasive tear film stability measurements obtained from the Keratograph was ≤8 seconds, and the optimal cutoff for breakup time measurements obtained from the Medmont was ≤14 seconds. Conclusions: Despite significant positive correlation, breakup time measurements obtained from the Keratograph and Medmont were not directly interchangeable. Measurements from the Medmont were significantly longer and demonstrated greater intra-subject and inter-subject variability, although the two automated, non-invasive methods for assessing tear film stability exhibited comparable overall performance in diagnosing dry eye disease.
Influence of the Blink Interval on Tear Meniscus Height in Soft Contact Lens and Nonlens Wearers
Eye & Contact Lens: Science & Clinical Practice, 2010
Purpose: Tear meniscus height (TMH) is an indirect measurement of tear film volume. This study investigated the temporal changes in the TMH during the blink interval in the morning (8 -9 AM) and at the end of the day (5-6 PM) in both soft contact lens (CL) and nonlens wearers (NLW). Methods: Fifty participants (25 CL; 25 NLW) were evaluated for their subjective symptoms, TMH, noninvasive break up time, and bulbar hyperemia at the AM and PM visits on the same day. The TMH was measured at set intervals between 2 and 15 sec during the blink interval, using an optical coherence tomographer. Results: The NLW group revealed no changes in a variety of symptoms during the day, whereas the CL group reported an increase in dryness (Pϭ0.03) and grittiness (Pϭ0.02) over the day. For both groups, the TMH and calculated tear meniscus volume revealed lower values immediately after the blink and increased progressively afterwards, mainly due to reflex tearing. The AM tear meniscus volume values tended to be higher than the PM values for both groups, but this was not significant (NLW Pϭ0.13; CL Pϭ0.82). Noninvasive break up time deteriorated during the day for both groups but was only significant for the CL group (Pϭ0.002), whereas bulbar hyperemia revealed no statistically significant change for either group. Conclusions: Reflex tearing may play a substantial role in the TMH differences observed over the blink interval. Standardization of the time when a TMH measurement is performed will be valuable in comparing tear film clinical studies.
The Agreement and Repeatability of Tear Meniscus Height Measurement Methods
Optometry and Vision Science, 2005
This study investigated the agreement and repeatability of five techniques of measuring tear meniscus height (TMH). Methods. Pairs of TMH measurements were obtained from one eye of 25 normal subjects with five techniques: optical coherence tomography in cross-section (OCT) and optical pachymetry in cross-section (PACH), without fluorescein; and 5 minutes after the instillation of fluorescein, optical pachymetry en-face (SL-F) and in cross-section (SL-X), and video capture en-face (VC). These 10 measurements were taken on different days within a period of 21 days. Additionally, immediately successive replicates were taken at the first visit when VC was used, allowing for the separation of technique repeatability from true day-today variation in TMH. Results. Ninety-five percent confidence intervals for the mean TMH and 95% repeatability coefficients for repeated testing on separate occasions were: 0.25 to 0.29 mm, 0.14 mm-OCT, 0.30 to 0.36 mm, 0.13 mm-PACH, 0.27 to 0.34 mm, 0.092 mm-SL-F, 0.35 to 0.41 mm, 0.19 mm-SL-X, and 0.30 to 0.38 mm, 0.088 mm-VC. Reported repeatability coefficients are averages because, despite a relatively narrow experimental range, the measurements of low TMH were generally more repeatable than those of large TMH. Ninety-five percent limits of agreement were wide for all pairwise comparisons and included zero, indicating that the methods used in this study are interchangeable when taking single recordings, at least on subjects without dry eye. Conclusions. The average TMH of the five techniques was similar, although OCT and SL-X tended to record lower and higher values, respectively. However, their agreement for single recordings was poor, an inevitable consequence of the low intertest repeatability found for all methods. A much improved repeatability for immediate replicates indicated that this, in turn, was principally caused by a large day-today variation in TMH rather than measurement error.
Reproducibility and repeatability of the OcuSense TearLab™ osmometer
Graefe's Archive for Clinical and Experimental Ophthalmology, 2012
Background Some studies report that increased tear osmolarity is a reliable indicator of dry eye syndrome (DES). The OcuSense TearLab™ osmometer requires less than a 100-nl sample of tears and provides an instant quantitative result. Our aim was to clinically evaluate this instrument in terms of its reproducibility and repeatability. Methods Twenty-nine participants who ranged in age from 19 to 49 years (mean±SD: 23.3±5.5 years) were recruited. Osmolarity readings were collected by two operators, in two sessions separated by 1 or 2 weeks in order to assess test reproducibility and repeatability. Results The coefficient of reproducibility was 39 mOsms/l; the coefficient of repeatability was 33 mOsms/l. Conclusions Our mean coefficient of variation over four readings for 29 subjects is 2.9%, which compares well with that reported by the manufacturer. Our results inform practitioners about the level of change over time that can be considered clinically relevant for healthy subjects. This value is 33mOsms/l; any change smaller than this could be attributed to measurement noise.
Agreement and repeatability of objective systems for assessment of the tear film
Graefe's archive for clinical and experimental ophthalmology = Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie, 2018
To assess the agreement and repeatability of two objective systems for measuring the tear film stability. Retrospective analysis of the tear film stability of 99 healthy right eyes measured with a videokeratoscope (VK) and the Optical Quality Analysis System (OQAS, Visiometrics). Two consecutive measures were taken with both systems, with an interval of 10 min between them. Variables included in the study were first and mean non-invasive break-up times (NIBUT and MNIBUT) measured with VK, and mean and standard deviation of the optical scattering index (OSIm and OSIsd) measured with OQAS. The agreement and repeatability of grading scales provided by both devices were also evaluated using the Cohen's k with quadratic weights. The Ocular Surface Disease index (OSDI) questionnaire was also passed out to all subjects. Correlations and associations between subjective and objective metrics were analyzed. Significant differences were found between consecutive measurements of NIBUT (p = ...
Clinical Optometry, 2018
Purpose: To assess the relationship between non-invasive tear break-up time (NITBUT) and maximum blink interval (MBI) values among young adults. Method: The study was conducted at Mzuzu University and involved 98 subjects (55 females and 43 males) aged between 18 and 40 years. All subjects were screened under the slit lamp, and were also asked questions to determine their eligibility to participate in the study. NITBUT measurements were taken by checking the discontinuity of the mires on the keratometer. MBI measurements were taken by observing the time period the subject could keep their eyes open without blinking. Results: There was a positive correlation (r=0.64, r 2 =0.418, P<0.001) between NITBUT and MBI values. The relationship between NITBUT and MBI values was similar in both males and females. Furthermore, the study showed that age, as well as gender, is not correlated to NITBUT and MBI values. Conclusion: There is a positive significant correlation (r=0.64, r 2 =0.418, P<0.001) between NITBUT and MBI values. There was no significant difference between the NITBUT and MBI values between males and females. The study has also discovered that there is no correlation between NITBUT and MBI with age and gender.
2015
Dry Eye Syndrome (DES) is a common disorder of the tear film which affects a significant sector of the population, impacting on quality of life. The diagnosis of this condition is difficult due to its multifactorial etiology, so there are a wide number of tests to evaluate different aspects of the tear film. Among the different tests available, the Break-up Time test (BUT) is a widely used measure to evaluate the quality and stability of the tear film on the ocular surface. It consists in measuring the time elapsed since the last blink until the tear film break-up, that is, the appearance of dark areas related to a thinning of the tear film on the surface of the eye. Besides the time, there are several break-up features such as the location, shape, size and dynamics of the breakup areas, which could affect to dry eye severity. However, the BUT test is affected by low repeatability mainly due to a subjective appreciation of the dark spots, the differences among the experts, and the variability of the tear film. Furthermore, the characterization by hand of break-up areas is a tedious and time consuming task. The automation of the break-up assessment would reduce its subjective character, allowing a more accurate evaluation of tear film stability. This work presents a novel methodology for a fully automatic assessment of the tear film break-up. The proposed methodology allows a quantitative, qualitative analysis of tear film instability, as an extension of BUT measurement, which is focused only on time. It provides accuracy results that are in the same ranges as the experts themselves. Therefore, the automated breakup assessment saves time for experts providing unbiased results which are not affected by subjective factors.
Repeatability and Diurnal Variation of Tear Ferning Test
Eye & Contact Lens-science and Clinical Practice, 2015
To investigate tear ferning test repeatability between sessions by observing changes in the tear fern pattern during the day. Methods: Twenty-three healthy young adults (15 male and 8 female), ranging in age from 20 to 32 years (mean±SD: 22.9±3.3 years) without signs or symptoms of dry eye disease, ocular disease or contact lens wear, were enrolled in the study. Schirmer I, tear break up time (TBUT) test and McMonnies questionnaire were used to screen volunteers. Schirmer I and TBUT tests were applied to both eyes in each subject. Four samples of tear fluid were collected from the right eye of each subject using glass capillaries, at set intervals during a single day (9am, 11am, 2pm and 4pm). The tear ferning (TF) patterns obtained from samples were classified according to the Masmali TF grading scale, to increments of 0.1. Results: The median values obtained from the McMonnies, Schirmer and TBUT tests were 4.0±2.0, 30.0±7.0mm (OD), and 16.0±10.0s (OD), respectively. There were no statistically significant differences between the TF grades for tear samples collected at different times of the day (Wilks' Lambda, p = 0.351). The majority (84.8%) of TF grades were between 0.0 and 1.5; the remaining 15.2% of subjects had TF between grades 1.6 and 1.9. The overall mean grade for the tear ferning was 1.1±0.3. There were small, insignificant correlations between TF grades and the McMonnies questionnaire (r = 0.1.30) and TBUT (r = 0.248), and a negligible correlation with Schirmer test (r = −0.046). Conclusions: The results found no significant differences within the tear ferning for tear samples collected at different times of the day, suggesting that there is little diurnal variation evident.
… Ophthalmology & Visual …, 2011
To evaluate tear film stability in patients with tear dysfunction and an asymptomatic control group by using the novel, noninvasive Tear Stability Analysis System (TSAS). METHODS. In this prospective case-control study, 45 patients with dysfunctional tear syndrome (DTS) were stratified into three groups (1, 2, and 3/4) based on clinical severity, with higher scores indicating more severe symptoms; 25 asymptomatic control subjects were evaluated. TSAS measurements were performed with the RT-7000 Auto Refractor-Keratometer (Tomey Corporation, Nagoya, Japan). Images of ring mires projected onto the cornea every second for 6 seconds were captured and analyzed. Focal changes in brightness were calculated as numerical ring breakup (RBU) values, and the elapsed time when the cumulative values (RBU sum) exceeded a threshold was defined as the ring breakup time (RBUT). RESULTS. RBUTs in the DTS groups were all significantly lower than those in the control subjects, with the lowest values found in DTS 3/4. RBUT was significantly shorter in DTS 3/4 than in DTS 1 (P Ͻ 0.001). The change in RBU sum over a 6-second period in the DTS groups combined or between the individual groups was statistically significant (P Ͻ 0.001), as was the difference between the 1-and 6-second values. For distinguishing between asymptomatic controls and DTS, the sensitivity and specificity of a 5.0-second RBUT cutoff were 82.0% and 60.0%, respectively. CONCLUSIONS. The TSAS may be a useful, noninvasive instrument for evaluating tear stability and for classifying DTS severity. (Invest Ophthalmol Vis Sci. 2011;52:456 -461)