Phase retardation and corneal sublayer thickness repeatability using ultrahigh resolution polarization-sensitive OCT

Rahul Patil, Rohit Shetty, Yash Patel, Anchana Pisharody, Raghav Narasimhan, Michael Pircher, Christoph K Hitzenberger, Rudy M M A Nuijts, Abhijit Sinha Roy*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

PURPOSE: To assess phase retardation and corneal sublayer thickness repeatability using ultrahigh resolution polarization-sensitive OCT (PS-OCT).

SETTING: Narayana Nethralaya eye hospital, Bangalore.

DESIGN: ObservationalMethods: In this study, all eyes were imaged using our custom-built ultrahigh resolution PS-OCT and high-resolution hybrid OCT (MS-39, CSO, Italy). We evaluated the repeatability of phase retardation en face maps and corneal sublayer thickness profiles. The reflectivity and phase retardation were calculated from the two orthogonal polarization channels to generate en face maps of phase retardation and corneal sublayer thicknesses. Three consecutive measurements of all subjects were acquired for each eye. For each measurement, the subject was asked to sit back and was re-aligned again. The repeatability was assessed using intraclass correlation coefficient (ICC).

RESULTS: The phase retardation en face maps showed preferential arrangement of collagen fibrils with least retardation in apex and maximum retardation in the periphery. The phase retardation showed excellent repeatability (ICC>0.95) in all zones. The Bowman's layer and stromal layer thicknesses were measured with excellent repeatability (ICC>0.93 and >0.99, respectively). Significant differences (p<0.05) in stromal layer thickness were observed between MS-39 and PS-OCT. The repeatability of epithelium thickness measurements was better with PS-OCT than MS-39.

CONCLUSION: The combinational assessment of corneal birefringence and sublayer thicknesses shows the advanced potential of ultrahigh resolution PS-OCT in routine clinical practice over current OCT devices.

Original languageEnglish
Pages (from-to)76-83
Number of pages8
JournalJournal of Cataract and Refractive Surgery
Volume49
Issue number1
Early online date16 Aug 2022
DOIs
Publication statusPublished - 1 Jan 2023

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