AUTHOR=Song Yi , Wu Di , Shen Min , Wang Like , Wang Congzheng , Cai Yong , Xue Chao , Cheng George P.M. , Zheng Yongping , Wang Yan 

TITLE=Measuring Human Corneal Stromal Biomechanical Properties Using Tensile Testing Combined With Optical Coherence Tomography

JOURNAL=Frontiers in Bioengineering and Biotechnology

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/bioengineering-and-biotechnology/articles/10.3389/fbioe.2022.882392

DOI=10.3389/fbioe.2022.882392

ISSN=2296-4185

ABSTRACT=<p><bold>Purpose:</bold> To investigate the <italic>ex vivo</italic> elastic modulus of human corneal stroma using tensile testing with optical coherence tomography (OCT) imaging and its correlation with <italic>in vivo</italic> measurements using corneal visualization Scheimpflug technology.</p><p><bold>Methods:</bold> Twenty-four corneal specimens extracted from stromal lenticules through small incision lenticule extraction were cut into strips for uniaxial tensile tests. <italic>In vivo</italic> corneal biomechanical responses were evaluated preoperatively using the corneal visualization Scheimpflug technology (CorVis ST). The correlation of the elastic modulus with clinical characteristics and dynamic corneal response parameters were analyzed using <italic>Spearman</italic>’<italic>s</italic> correlation analysis.</p><p><bold>Results:</bold> The mean low strain tangent modulus (LSTM) of the human corneal stroma was 0.204 ± 0.189 (range 0.010–0.641) MPa, and high strain tangent modulus (HSTM) 5.114 ± 1.958 (range 2.755–9.976) MPa. Both LSTM (<italic>r</italic> = 0.447, <italic>p</italic> = 0.029) and HSTM (<italic>r</italic> = 0.557, <italic>p</italic> = 0.005) were positively correlated with the stress-strain index (SSI). LSTM was also positively correlated with the A1 deflection length (<italic>r</italic> = 0.427, <italic>p</italic> = 0.037) and A1 deflection area (<italic>r</italic> = 0.441, <italic>p</italic> = 0.031). HSTM was positively correlated with spherical equivalent (<italic>r</italic> = 0.425, <italic>p</italic> = 0.038).</p><p><bold>Conclusions:</bold> The correlation of corneal elastic modulus with A1 deflection parameters and SSI may indicate a relationship between these parameters and tissue elasticity. The HSTM decreased with the degree of myopia. Combining tensile test with OCT may be a promising approach to assess corneal biomechanical properties.</p>