HIGH-RESOLUTION OCT-ELASTOGRAPHY ASSESSING BIOMECHANICS IN NORMAL AND KERATOCONUS SUBJECTS
Published 2023
- 27th ESCRS Winter Meeting
Reference: O24
| Type: Free Paper Submission
| DOI:
10.82333/4yve-2423
Authors:
Emilio A. Torres-Netto* 1
, Matteo Frigelli 2
, Farhad Hafezi 1
, Sabine Kling 3
1ELZA Institute & University of Zurich,Zurich,Switzerland, 2ARTORG Center for Biomedical Engineering Research, University of Bern,Bern,Switzerland, 3Computer Vision OPTIC team, Computer Vision Laboratory, ETH Zurich,Zurich,Switzerland
Purpose
To investigate the suitability of small-amplitude ambient pressure modulation combined with optical coherence tomography (OCT) to discern healthy from keratoconic corneas in vivo.
Setting
The study was performed at the ELZA Institute AG, Dietikon (Switzerland) in collaboration with ETH Zurich and the University of Bern.
Methods
Analyses were conducted in 4 progressive keratoconus patients and 3 healthy individuals. A commercial anterior segment OCT system was combined with an external pressure unit for biomechanical assessment. In a single measurement, 128 subsequent B-scans were recorded (approx. 2.5 seconds duration), while the ambient pressure in front of the eye was suddenly reduced by 6.1 +/- 1.3 mmHg. The raw OCT signal was exported and a complex vector summation approach was adopted to compute the displacement between subsequent A-lines, as well as the axially induced strain. To increase the signal-to-noise ratio, the signal from within the optical zone was averaged.
Results
KC corneas presented a positive posterior displacement (0.4 nm/mmHg), while healthy corneas presented a negative posterior displacement (-1.8 nm/mmHg), both with respect to the mid-corneal region. Differences were significant with p=0.009.
Conclusion
Non-invasive corneal biomechanical evaluation under close-to-physiologic stress conditions allows for the differentiation between normal and keratoconus corneas and is a promising approach in the diagnosis of anterior segment degenerative diseases.