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Proceedings Paper

Influence of corneal hydration on optical coherence elastography
Author(s): Michael D. Twa; Srilatha Vantipalli; Manmohan Singh; Jiasong Li; Kirill V. Larin
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Paper Abstract

Corneal biomechanical properties are influenced by several factors, including intraocular pressure, corneal thickness, and viscoelastic responses. Corneal thickness is directly proportional to tissue hydration and can influence corneal stiffness, but there is no consensus on the magnitude or direction of this effect. We evaluated the influence of corneal hydration on dynamic surface deformation responses using optical coherence elastography (OCE). Fresh rabbit eyes (n=10) were prepared by removing the corneal epithelium and dropping with 0.9% saline every 5 minutes for 1 hour, followed by 20% dextran solution every 5 minutes for one hour. Corneal thickness was determined from structural OCT imaging and OCE measurements were performed at baseline and every 20 minutes thereafter. Micron-scale deformations were induced at the apex of the corneal tissue using a spatially-focused (150μm) short-duration (<1ms) air-pulse delivery system. These dynamic tissue responses were measured non-invasively with a phase-stabilized swept source OCT system. The tissue surface deformation response (Relaxation Rate: RR) was quantified as the time constant, over which stimulated tissue recovered from the maximum deformation amplitude. Elastic wave group velocity (GV) was also quantified and correlated with change in corneal thickness due to hydration process. Corneal thickness rapidly increased and remained constant following epithelium removal and changed little thereafter. Likewise, corneal stiffness changed little over the first hour and then decreased sharply after Dextran application (thickness: -46% [-315/682 μm]; RR: - 24% [-0.7/2.88 ms-1]; GV: -19% [-0.6/3.2 m/s]). Corneal thickness and corneal stiffness (RR) were well correlated (R2 = .66). Corneal biomechanical properties are highly correlated with tissue hydration over a wide range of corneal thickness and these changes in corneal stiffness are quantifiable using OCE.

Paper Details

Date Published: 4 March 2016
PDF: 8 pages
Proc. SPIE 9693, Ophthalmic Technologies XXVI, 96930V (4 March 2016); doi: 10.1117/12.2210756
Show Author Affiliations
Michael D. Twa, The Univ. of Alabama at Birmingham (United States)
Srilatha Vantipalli, Univ. of Houston (United States)
Manmohan Singh, Univ. of Houston (United States)
Jiasong Li, Univ. of Houston (United States)
Kirill V. Larin, Univ. of Houston (United States)
Tomsk State Univ. (Russian Federation)
Baylor College of Medicine (United States)

Published in SPIE Proceedings Vol. 9693:
Ophthalmic Technologies XXVI
Fabrice Manns; Per G. Söderberg; Arthur Ho, Editor(s)

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