J Korean Ophthalmol Soc.  2016 Sep;57(9):1354-1360. 10.3341/jkos.2016.57.9.1354.

Reliability of a New Non-invasive Tear Film Break-up Time Measurement Using a Keratograph

• Jeong S
• Lee SB

• KMID: 2351864
• DOI: http://doi.org/10.3341/jkos.2016.57.9.1354

Abstract

PURPOSE
To evaluate the repeatability of non-invasive tear film break-up time and identify its relationships with dry eye parameters.
METHODS
A total of 100 participants (50 with dry eye, and 50 in the control group) were enrolled prospectively. Non-invasive keratograph first (NIKf-BUT) and average (NIKav-BUT) break-up times were evaluated 2 times using Keratograph 4 (Oculus, Wetzler, Germany), and then tear film break-up time with fluorescein (FBUT) was measured. The correlation analyses were performed between non-invasive parameters (NIKf-BUT and NIKav-BUT) and FBUT. Intra-observer agreements of NIKf-BUT and NIKav-BUT were assessed using intraclass correlation coefficients (ICC). The receiver operating characteristic (ROC) curve technique was used to evaluate the non-invasive method in the diagnosis of dry eye.
RESULTS
The correlation analyses revealed positive correlation between NIKav-BUT and FBUT in both groups (dry eye; r = 0.66, p < 0.001 and control group; r = 0.77, p < 0.001). The ICCs of NIKf-BUT and NIKav-BUT were 0.72 and 0.94 in the dry eye, respectively, and 0.70 and 0.91 in the control group. NIKav-BUT was not different from FBUT in either group. The areas under the ROC curves of NIKf-BUT and NIKav-BUT were 0.917 and 0.980, respectively.
CONCLUSIONS
The high ICCs verified the repeatability of NIKf-BUT and NIKav-BUT. NIKav-BUT showed no difference from FBUT and positive correlation with FBUT. NIK-BUT showed high diagnostic power and can be considered a new parameter to evaluate dry eye syndrome.

Keyword

Correlation; Dry eye; Keratograph 4; Non-invasive tear film break-up time; Repeatability

MeSH Terms

Diagnosis
Dry Eye Syndromes
Fluorescein
Methods
Prospective Studies
ROC Curve
Tears*
Fluorescein

Figure

• 

  Figure 1. Representative image of non-invasive keratograph tear film break-up time (NIK-BUT) using Oculus Keratograph 4 (Oculus, Wetzler, Germany). (A) A real time image recorded the entire course of break up process. Placido rings were reflected from surface of cornea and their distortions were recorded as the red-framed rectangular break-up units. (B) The final report was summarized as tear film break-up colour-code map. (C) Noninvasive keratograph first break-up time (NIKf-BUT), non-invasive keratograph average break-up time (NIKav-BUT) and break-up progress of break-up units were provided.

• 

  Figure 2. Distribution of non-invasive keratograph tear film break-up time (NIK-BUT) and tear film break-up time with fluorecein (FBUT) using box and whisker plot in the dry eye and control groups. The boxes include 50% of the measured values between 1st and 3rd quartiles and the median (horizontal line). The upper and lower fences indicate 1.5 times the interquartile range (IQR) from 3rd and 1st quartiles. The outliers which are more than 1.5 IQR from the box are shown as circles. The mean of each parameter are shown as diamond. Comparison between FBUT and NIK-BUTs was performed by paired sample t-test. NIKf-BUT = non-invasive keratograph first break-up time; NIKav-BUT = non-invasive keratograph average break-up time.* p-value < 0.05 by paired sample t-test.

• 

  Figure 3. Receiver operating characteristic curve (ROC) of non-invasive keratograph tear film break-up time (NIK-BUT). The area under the curve (AUC) is 0.917 in 1st non-invasive keratograph first break-up time (NIKf-BUT) and 0.980 in 1st non-invasive keratograph average break-up time (NIKav-BUT). The cutoff value derived from ROC curve was provided. The difference of AUC between NIKf-BUT and NIKav-BUT was 0.063 and was significant (p = 0.032).

Reference

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