Imaging the Tear Film: A Comparison Between the Subjective Keeler Tearscope-Plus™ and the Objective Oculus® Keratograph 5M and LipiView® Interferometer

Abstract

Purpose: To compare non-invasive break-up time (NIBUT) when measured with the Tearscope-Plus™ and the Oculus® Keratograph 5M, and to compare lipid layer thicknesses (LLT) when measured with the Tearscope-Plus™ and the LipiView®. This study also set out to establish the repeatability of these methods.

Methods: The following measurements were taken from both eyes of 24 participants on two occasions: non-invasive keratograph break-up time using the Oculus® (NIKBUT-1 and NIKBUT-average), NIBUT using the Tearscope-Plus™, and LLT using the LipiView® (minimum, maximum, and average) and Tearscope-Plus™. The Tearscope-Plus™ grades were converted to nanometers.

Results: There were no significant differences between eyes (Tearscope-Plus™ NIBUT: p = 0.52; NIKBUT-1: p = 0.052; NIKBUT-average: p = 0.73; Tearscope-Plus™ LLT: p = 0.13; LipiView® average, maximum, or minimum: p = 0.68, 0.39 and 0.50, respectively) or days (Tearscope-Plus™ NIBUT: p = 0.32; NIKBUT-1: p = 0.65; NIKBUT-average: p = 0.54; Tearscope-Plus™ LLT: p = 0.26; LipiView® average, maximum, or minimum: p = 0.20, 0.09, and 0.10, respectively). LLT was significantly greater with the Tearscope-Plus™ (80.4 ± 34.0 nm) compared with the LipiView® average (56.3 ± 16.1 nm, p = 0.007), minimum (50.1 ± 15.8 nm, p < 0.001) but not maximum (67.2 ± 19.6 nm, p = 0.55). NIBUT was significantly greater with the Tearscope-Plus™ (15.9 ± 10.7 seconds) compared to the NIKBUT-1 (8.2 ± 3.5 seconds, p = 0.006) but not NIKBUT-average (10.9 ± 3.9 seconds, p = 0.08).

Conclusions: The Tearscope-Plus™ is not interchangeable with either the Oculus® K5M measurement of tear stability (NIKBUT-1) or the LipiView® maximum and minimum lipid thickness.

Keywords: Tear break-up time; dry eye disease; lipid layer thickness; repeatability.