<i>In Vivo</i> Corneal Stiffness Mapping by the Stress-Strain Index Maps and Brillouin Microscopy

Lopes, Bernardo T ORCID: 0000-0002-8489-3621 and Elsheikh, Ahmed ORCID: 0000-0001-7456-1749
(2023) <i>In Vivo</i> Corneal Stiffness Mapping by the Stress-Strain Index Maps and Brillouin Microscopy. Current Eye Research, 48 (2). pp. 1-7.

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The study of corneal stiffness <i>in vivo</i> has numerous clinical applications such as the measurement of intraocular pressure, the preoperative screening for iatrogenic ectasia after laser vision correction surgery and the diagnosis and treatment of corneal ectatic diseases such as keratoconus. The localised aspect of the microstructure deterioration in keratoconus leading to local biomechanical softening, corneal bulging, irregular astigmatism and ultimately loss of vision boosted the need to map the corneal stiffness to identify the regional biomechanical failure. Currently, two methods to map the corneal stiffness <i>in vivo</i> are integrated into devices that are either already commercially available or about to be commercialised: the stress-strain index (SSI) maps and the Brillouin Microscopy (BM). The former method produces 2D map of stiffness across the corneal surface, developed through numerical simulations using the corneal shape, its microstructure content, and the deformation behaviour under air-puff excitation. It estimates the whole stress-strain behaviour, making it possible to obtain the material tangent modulus under different intraocular pressure levels. On the other hand, BM produces a 3D map of the corneal longitudinal modulus across the corneal surface and thickness. It uses a low-power near-infrared laser beam and through a spectral analysis of the returned signal, it assesses the mechanical compressibility of the tissue as measured by the longitudinal modulus. In this paper, these two techniques are reviewed, and their advantages and limitations discussed.

Item Type: Article
Uncontrolled Keywords: Cornea, biomechanics, mapping, ectasia, keratoconus
Divisions: Faculty of Science and Engineering > School of Engineering
Depositing User: Symplectic Admin
Date Deposited: 31 May 2022 15:46
Last Modified: 20 Mar 2023 13:47
DOI: 10.1080/02713683.2022.2081979
Related URLs:
URI: https://livrepository.liverpool.ac.uk/id/eprint/3155741