TechniquesMapping the Lipid Layer of the Human Tear FilmCohen, Yoel PhD*; Trokel, Stephen MD†; Arieli, Yoel PhD‡; Epshtien, Shlomi MSc*; Gefen, Raanan MSc*; Harris, Alon PhD, FARVO§Author Information *AdOM Advanced Optical Methods, Lod, Israel; †Harkness Eye Institute,Columbia University, New York, NY; ‡The Jerusalem College of Technology, Jerusalem, Israel; and §School of Medicine, Glick Eye Institute, Indiana University, Indianapolis, IN. Correspondence: Yoel Arieli, PhD, the Jerusalem College of Technology, Havaad Haleumi 21, Jerusalem 9116001, Israel, (e-mail: firstname.lastname@example.org). This study was supported by the Israel Innovation Authority, Grant numbers 52259 and 53285. The Tear Film Imager device was provided by AdOM Advanced Optical Technologies Ltd. Y. Arieli and A. Harris: equity and consulting to AdOM, advanced optical methods Ltd. A. Harris: receives remuneration from CIPLA and Shire for serving as a consultant. The remaining authors have no conflicts of interest to disclose. Cornea: January 2020 - Volume 39 - Issue 1 - p 132-135 doi: 10.1097/ICO.0000000000002101 Buy Metrics Abstract Purpose: To describe a new method to distinguish between normal versus lipid-deficient dry eye using a Tear Film Imager (TFI). Methods: Two groups of study subjects, controls versus lipid-deficient dry eye, were tested using the TFI. This instrument provides an accurate measurement of the thickness and spatial distribution of the muco-aqueous and lipid layers of the tear film. The nanometer thickness resolution of the TFI enables the creation of detailed maps of the lipid layer thickness (LLT) across the corneal surface. These maps are captured with a large field of view of 6.5 mm diameter. Results: A LLT map taken at 1 second from a blink end in the controls appears uniform, whereas a nonuniform layer was measured in the lipid-deficient dry eye. Lipid map uniformity can quantify the spatial variation of lipid across the cornea. A case study showed the ability to distinguish between controls [lipid map uniformity (LMU) = 14 nm2] and lipid-deficient dry eye (LMU = 125 nm2) through characterization of the LLT distribution. Conclusions: High-resolution lateral LLT maps demonstrate the significance of the lipid layer uniformity, which may play an important role in maintaining tear film health. LLT maps and the quantitative LMU could be used to diagnose and treat patients with dry eye. Copyright © 2019 Wolters Kluwer Health, Inc. All rights reserved.