Agreement between Automated and Traditional Measures of Tear Film Breakup

Abstract

Purpose To determine repeatability and agreement between the non-invasive tear break up time (NIK-BUT) as measured by the Oculus Keratograph 4 and fluorescein tear break up time (FBUT). Methods Sixty subjects were recruited for two study visits separated by 7 (± 2) days. At each visit, three NIK-BUT measures and FBUT measures were obtained. Each NIK-BUT measure from the Keratograph included a first and an average NIK-BUT. The means of the measures obtained, first NIK-BUT, average NIK-BUT and FBUT, were calculated for each visit. Between- and within-visit agreement was assessed using intraclass correlation coefficients (ICCs) and Bland-Altman 95% limits of agreement (LoA) analyses of log-transformed data. Results Between-visit ICCs were 0.53 (95% CI, 0.32-0.69) for first NIK-BUT, 0.59 (95% CI, 0.40-0.73) for average NIK-BUT, and 0.66 (95% CI, 0.49-0.78) for FBUT, whereas 95% LoA were -0.65 to 0.67, -0.44 to 0.48, and -1.14 to 1.10, [back transformed: (visit 1 + 0.01) / (visit 2 + 0.01) = 0.22 to 4.68, 0.36 to 3.02, and 0.07 to 12.59] for the aforementioned methods, respectively. The visit one within-visit ICC between first NIK-BUT and FBUT was 0.44 (95% CI, 0.21-0.62), whereas the 95% LoA was -0.84 to 1.18 [back transformed: (first NIK-BUT + 0.01) / (FBUT + 0.01) = 0.14 to 15.14]. Likewise, the visit one within-visit ICC between average NIK-BUT and FBUT was 0.41 (95% CI, 0.18-0.60), whereas the 95% LoA was -0.58 to 1.44 [back transformed: (average NIK-BUT + 0.01) / (FBUT + 0.01) = 0.26 to 27.54]. Conclusions The 95% LoA suggest that the average NIK-BUT has better between-visit agreement compared to the first NIK-BUT or FBUT. The first NIK-BUT showed better within-visit agreement with the FBUT than the average NIK-BUT. In addition, there is better between- and within-visit agreement for all measures at lower values.

TFOS DEWS II Tear Film Report

“…Acquiring a TBUT is a relatively simple task, but interpreting the result is not straightforward because of its inherent variability [80,81]. A number of approaches to improving repeatability have been suggested, including taking multiple readings and averaging or selecting a subset of values [82,83], minimizing the amount of fluorescein instilled [84–86] and, most significantly, eliminating the use of fluorescein altogether.…”

Influence of Pars Plana Vitrectomy on Ocular Surface using Non-Invasive Keratograph 5M

“…Oculus Keratograph can detect the very early changes of tear film and record very low NITBUT objectively with high reliability and repeatability [14,15]. Stephanie et al reported that NITBUT measured by Keratograph 4 can be substituted for the numerical fluorescein TBUT value [16]. The present study recorded the changes of both NITBUT-first and NITBUT-average after PPV via Keratograph 5M.…”

“…Additionally, these invasive examinations have been shown to have poor accuracy and reproducibility. The noninvasive Keratography 5M, advanced Placido topograph, provides reliable objective measurements of ocular surface parameters including tear meniscus height (TMH), noninvasive TBUT (NITBUT) and bulbar redness score, with acceptable repeatability and reproducibility [7,8]. It has been used in evaluation of ocular surface in recent years, especially the diagnosis of dry eye.…”

Advances in dry eye imaging: the present and beyond

“…Both NITBUT f and NITBUT avg are correlated with Ocular Surface Disease Index (OSDI) score 11. NITBUT f has better within-visit agreement with FTBUT than NITBUT avg 12 A 12.1 s NITBUT f has a 82% sensitivity and 94% specificity while a 5 s RBUT cut-off has a 82% sensitivity and 60% specificity in distinguishing DED from healthy subjects 10 13. These different platforms and algorithms have poor agreement among themselves and are not interchangeable 14.…”