Automatic assessment of tear film and tear meniscus parameters in healthy subjects using ultrahigh-resolution optical coherence tomography.

Hannes Stegmann,Alina Messner,René Marcel Werkmeister,Doreen Schmidl,Leopold Schmetterer,Valentin Aranha Dos Santos,Angelika Unterhuber,Gerhard Garhöfer

doi:10.1364/boe.10.002744

Abstract

Many different parameters exist for the investigation of tear film dynamics. We present a new tear meniscus segmentation algorithm which automatically extracts tear meniscus area (TMA), height (TMH), depth (TMD) and radius (TMR) from UHR-OCT measurements and apply it to a data set including repeated measurements from ten healthy subjects. Mean values and standard deviations are 0.0174 ± 0.007 mm2, 0.272 ± 0.069 mm, 0.191 ± 0.049 mm and 0.309 ± 0.123 mm for TMA, TMH, TMD and TMR, respectively. A significant correlation was found between all respective tear meniscus parameter pairs (all p < 0.001, all Pearson's r ≥ 0.657). Challenges, limitations and potential improvements related to the data acquisition and the algorithm itself are discussed. The automatic segmentation of tear meniscus measurements acquired with UHR-OCT might help in a clinical setting to further understand the tear film and related medical conditions like dry eye disease.

Highlights

Dry eye disease (DED) is a highly prevalent [1,2] disease of the tears and ocular surface, yet remains not fully understood due to its complex and multifactorial aspects. It can be divided into aqueous-deficient dry eye (ADDE) and evaporative dry eye (EDE), according to the different causes of the disease
Employing an ultrahigh-resolution (UHR-)optical coherence tomography (OCT) system based on a Ti:Sapphire laser [6,24], we achieved an axial resolution of approximately 1.2 μm in tissue, allowing to image the tear meniscus, and to fully resolve and measure the thickness of the much thinner precorneal tear film
Partial correlation coefficients were computed for tear film thickness (TFT), tear meniscus area (TMA), TMH, TMD, TMR and lipid layer thickness (LLT) (Table 2)

Summary

Introduction

Dry eye disease (DED) is a highly prevalent [1,2] disease of the tears and ocular surface, yet remains not fully understood due to its complex and multifactorial aspects. It can be divided into aqueous-deficient dry eye (ADDE) and evaporative dry eye (EDE), according to the different causes of the disease. Employing an ultrahigh-resolution (UHR-)OCT system based on a Ti:Sapphire laser [6,24], we achieved an axial resolution of approximately 1.2 μm in tissue, allowing to image the tear meniscus, and to fully resolve and measure the thickness of the much thinner precorneal tear film. Considerable efforts have been made in the past to study the above mentioned parameters and find possible correlations between them in order to better understand tear film dynamics and to better characterize diseases like DED [28,29]

Methods

Results

Discussion

Conclusion