Joel R Palko1, Junhua Tang1, Benjamin Cruz Perez1, Xueliang Pan1, Jun Liu2. 1. From the College of Medicine (Palko), the Department of Biomedical Engineering (Tang, Perez, Liu), the Center for Biostatistics (Pan), and the Department of Ophthalmology (Liu), Ohio State University, Columbus, Ohio, USA. 2. From the College of Medicine (Palko), the Department of Biomedical Engineering (Tang, Perez, Liu), the Center for Biostatistics (Pan), and the Department of Ophthalmology (Liu), Ohio State University, Columbus, Ohio, USA. Electronic address: liu.314@osu.edu.
Abstract
PURPOSE: To determine the heterogeneous through-thickness strains in the cornea at physiologic intraocular pressures before and after corneal collagen crosslinking (CXL) using noninvasive ultrasound. SETTING: Department of Biomedical Engineering, Ohio State University, Columbus, Ohio, USA. DESIGN: Experimental study. METHODS: Sixteen paired canine corneoscleral shells were divided into 2 groups. The CXL group completed a standard CXL protocol using riboflavin-ultraviolet-A (UVA) irradiation. The control group was given an identical treatment except UVA irradiation. Ultrasound scans (at 55 MHz) of the cornea were obtained before and after treatment as the corneoscleral shell was inflated from 5 mm Hg to 45 mm Hg to calculate the distributive through-thickness strains in the cornea. The mean radial and tangential strains of the whole cornea layer, as well as those of the anterior, middle, and posterior thirds of the cornea, were compared before and after treatment in the control group and CXL group using linear mixed models with repeated measures. RESULTS: Significant reductions in tangential and radial strains occurred in the CXL group (P=.003 and P=.0025, respectively) but not the control group (P=.08 and P=.63, respectively). The anterior third had the smallest strains in all pretreated corneas (P<.001) and posttreated corneas (CXL group, P=.023; control group, P=.01). CONCLUSIONS: Ultrasound speckle tracking showed heterogeneous strain distributions through the cornea and confirmed that CXL results in a stiffer corneal response (ie, smaller strains during physiologic loadings). This technique may provide a clinical tool to quantify the biomechanical effects of CXL. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.
PURPOSE: To determine the heterogeneous through-thickness strains in the cornea at physiologic intraocular pressures before and after corneal collagen crosslinking (CXL) using noninvasive ultrasound. SETTING: Department of Biomedical Engineering, Ohio State University, Columbus, Ohio, USA. DESIGN: Experimental study. METHODS: Sixteen paired canine corneoscleral shells were divided into 2 groups. The CXL group completed a standard CXL protocol using riboflavin-ultraviolet-A (UVA) irradiation. The control group was given an identical treatment except UVA irradiation. Ultrasound scans (at 55 MHz) of the cornea were obtained before and after treatment as the corneoscleral shell was inflated from 5 mm Hg to 45 mm Hg to calculate the distributive through-thickness strains in the cornea. The mean radial and tangential strains of the whole cornea layer, as well as those of the anterior, middle, and posterior thirds of the cornea, were compared before and after treatment in the control group and CXL group using linear mixed models with repeated measures. RESULTS: Significant reductions in tangential and radial strains occurred in the CXL group (P=.003 and P=.0025, respectively) but not the control group (P=.08 and P=.63, respectively). The anterior third had the smallest strains in all pretreated corneas (P<.001) and posttreated corneas (CXL group, P=.023; control group, P=.01). CONCLUSIONS: Ultrasound speckle tracking showed heterogeneous strain distributions through the cornea and confirmed that CXL results in a stiffer corneal response (ie, smaller strains during physiologic loadings). This technique may provide a clinical tool to quantify the biomechanical effects of CXL. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.
Authors: Keyton Clayson; Thomas Sandwisch; Yanhui Ma; Elias Pavlatos; Xueliang Pan; Jun Liu Journal: Curr Eye Res Date: 2019-09-18 Impact factor: 2.424
Authors: Keyton Clayson; Xueliang Pan; Elias Pavlatos; Ryan Short; Hugh Morris; Richard T Hart; Jun Liu Journal: Exp Eye Res Date: 2017-08-30 Impact factor: 3.467
Authors: Elias Pavlatos; Benjamin Cruz Perez; Hugh J Morris; Hong Chen; Joel R Palko; Xueliang Pan; Paul A Weber; Richard T Hart; Jun Liu Journal: J Biomech Eng Date: 2016-02 Impact factor: 2.097
Authors: Benjamin Cruz Perez; Elias Pavlatos; Hugh J Morris; Hong Chen; Xueliang Pan; Richard T Hart; Jun Liu Journal: Ann Biomed Eng Date: 2015-11-12 Impact factor: 3.934