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Michael D Twa, Srilatha Vantipalli, Manmohan Singh, Jiasong Li, Kirill Larin; Corneal Thickness is Positively Correlated with Tissue Elasticity by Elastography Imaging. Invest. Ophthalmol. Vis. Sci. 2016;57(12):2373. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Corneal thickness and hydration varies considerably in normal and diseased eyes. There are conflicting reports from previous studies regarding the influence of tissue hydration on corneal biomechanics. Here we evaluated corneal elasticity as a function of corneal thickness using optical coherence elastography (OCE).
Fresh whole rabbit eyes (n=10) were deepithelialized, then treated with 0.9% saline every 5 minutes for 60 minutes, followed by 20% Dextran every 5 minutes for 60 minutes. A focused air pulse system was used to induce low amplitude (≤ 10 μm) tissue deformation at the corneal apex that was imaged using a phase-stabilized swept source optical coherence tomography system. Tissue elasticity was measured along with total corneal thickness every 20 minutes. Tissue elasticity was quantified by the dynamic natural frequency, which previous work has shown is linearly related to the square root of Young’s modulus.
Although corneal thickness changed little over the saline treatment period, measured elasticity changed by 4% (P > .05). Dextran treatment reduced corneal thickness by 250 μm and reduced measured corneal elasticity by 30% (P < .0001). These two parameters were highly correlated (R2 = .980; P = .0001).
Corneal thickness changes due to variations in tissue hydration are positively correlated with measured tissue elasticity by OCE. Further studies are needed to help separate the effects due to corneal thickness alone and those due to corneal hydration, which may affect both elastic and viscous components of the observed viscoelastic response.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
Average central corneal thickness and elasticity of whole fresh rabbit eyes (n=10) over time. Deepithelialized corneas were treated with 0.9% saline every 5 minutes for 60 minutes, then with 20% dextran. Central corneal thickness was measured using OCT and elasticity was quantified as the dynamic natural frequency from optical cohernce elastograhy imaging.
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