High Resolution Optical Coherence Elastography: Clinical Evaluation Of Normal And Keratoconus Corneas
Published 2023 - 41st Congress of the ESCRS
Reference: FP18.10 | Type: Free paper | DOI: 10.82333/3tsw-kh19
Authors: Mark Hillen 1 , Matteo Frigelli 2 , Emilio A. Torres-Netto 3 , M. Enes Aydemir 4 , Nanji Lu 5 , Farhad Hafezi* 6 , Sabine Kling 7
1Ophthalmology,ELZA Institute,Dietikon/Zurich,Switzerland, 2ARTORG Center for Biomedical Engineering Research,University of Bern,Bern,Switzerland, 3Ophthalmology,ELZA Institute,Dietikon/Zurich,Switzerland;Ocular Cell Biology Laboratory,University of Zurich,Zurich,Switzerland, 4Ophthalmology,ELZA Institute,Zurich,Switzerland, 5Faculty of Medicine and Health Sciences,University of Antwerp,Wilrijk,Belgium;Ophthalmology,ELZA Institute,Zurich,Switzerland, 6Ophthalmology,ELZA Institute,Zurich,Switzerland;Ocular Cell Biology Laboratory,University of Zurich,Zurich,Switzerland, 7OPTIC-team, Computer Vision Laboratory,ETH Zurich,Zurich,Switzerland;ARTORG Center for Biomedical Engineering Research,University of Bern,Bern,Switzerland
Purpose
Optical coherence elastography (OCE) is an emerging technology capable of detecting localized biomechanical alterations by inducing tissue deformation and concurrently capturing images through optical coherence tomography (OCT). In this study, we evaluated the potential of OCE, employing ambient pressure modulation for corneal deformation, to distinguish between normal and keratoconic corneas in vivo.
Setting
University of Zurich, CABMM; OPTIC team, Computer Vision Laboratory, ETH Zurich; ELZA Institute, Dietikon/Zurich, Switzerland
Methods
In this study, nine healthy participants and 15 patients with progressive keratoconus (KC) underwent OCE measurements. Customized swimming goggles, connected to an external pressure modulation unit, were worn by the participants. Over a period of approximately 2.6 seconds, 128 consecutive, repetitive B-scans were recorded. After 0.55 seconds, the goggle pressure decreased by 10 mmHg. The resulting corneal deformation was quantified using a phase-based displacement and strain computation methodology.
Results
The overall corneal strain exhibited positive values in KC cases and negative values in healthy corneas. By the end of the measurement, KC and healthy corneas had accumulated a posterior strain of 1.80±0.77‰ and -2.22±0.62‰ (p=0.001), respectively. No significant difference was observed in anterior strain (p=0.62). In terms of the central cornea, anterior KC corneas displayed a tendency to move forward further on average compared to healthy corneas (84±37nm vs. -55±58nm, p=0.054).
Conclusions
Optical coherence elastography demonstrates the ability to clinically distinguish between normal and keratoconic corneas by analyzing in-depth corneal strain. This technology enables the identification of localized biomechanical alterations in the cornea, and potentially paves the way for advances in keratoconus diagnosis and monitoring ectasia progression.