MSA  Vol.9 No.7 , June 2018
Non-Invasive and Non-Destructive Determination of Corneal and Scleral Biomechanics Using Vibrational Optical Coherence Tomography: Preliminary Observations
Abstract: Experimental measurements made in this study on human and porcine eyes suggest that the resonant frequency for both cornea and sclera varies from 130 to 150 Hz and increases slightly with increasing intraocular pressure. The values of the moduli calculated using the experimental values of the thickness are close to 2 MPa. Similar values of the modulus for cornea and sclera suggest that there is very little stress concentration at the cornea-scleral junction and that any stress concentration that occurs probably resides at the scleral attachment laterally and posteriorly. These moduli are close to those measured in vivo on human skin suggesting that the mechanism of tensile deformation of skin, cornea and sclera are similar. Our results suggest that the modulus of cornea and sclera can be measured non-invasively and non-destructively using vibrational OCT. Results of these studies will assist clinicians to better understand the influence of biomechanics on the outcome of corneal refractive surgery as well as the pathogenesis of eye disorders such as glaucoma, myopia and keratoconus.
Cite this paper: Silver, F. , Shah, R. and Benedetto, D. (2018) Non-Invasive and Non-Destructive Determination of Corneal and Scleral Biomechanics Using Vibrational Optical Coherence Tomography: Preliminary Observations. Materials Sciences and Applications, 9, 657-669. doi: 10.4236/msa.2018.97047.

[1]   Benedict, G. (1971) Theory of Transparency of the Eye. Applied Optics, 10, 459-473.

[2]   Jue, B. and Maurice, D.M. (1986) The Mechanical Properties of the Rabbit and Human Cornea. Journal of Biomechanics, 19, 847-853.

[3]   Andreassan, T.T., Simonsen, A.H. and Oxlund, H. (1980) Bio-mechanical Properties of Keratoconus and Normal Corneas. Experimental Eye Research, 31, 435-441.

[4]   Roberts, C.J. (2014) Concepts and Misconceptions in Corneal Biomechanics. Journal of Cataract & Refractive Surgery, 40, 862-869.

[5]   Dupps Jr., W.J. and Wilson, S.E. (2006) Biomechanics and Wound Healing in the Cornea. Experimental Eye Research, 83, 709-720.

[6]   Ruberti, J.W., Roy, A.S., Cynthia, J. and Roberts, C.J. (2011) Corneal Biomechanics and Biomaterials. Annual Review of Biomedical Engineering, 13, 269-295.

[7]   Wollensak, G. and Iomdina, E. (2009) Biomechanical and Histological Changes after Corneal Crosslinking with and without Epithelial Debridement. Journal of Cataract & Refractive Surgery, 35, 540-546.

[8]   Ambekara, R., Kimani, C., Toussaint Jr., B. and Johnson, A.W. (2011) The Effect of Keratoconus on the Structural, Mechanical, and Optical Properties of the Cornea. Journal of the Mechanical Behavior of Biomedical Materials, 4, 223-236.

[9]   Nash, I.S., Peter, R., Green, P.R. and Foster, C.S. (1982) Comparison of Mechanical Properties of Keratoconus and Normal Corneas. Experimental Eye Research, 35, 413-423.

[10]   Elsheikh, A. and Alhasso, D. (2009) Mechanical Anisotropy of Porcine Cornea and Correlation with Stromal Microstructure. Experimental Eye Research, 88, 1084-1091.

[11]   Elsheikh, A., Geraghty, B., Alhasso, D., Knappett, J., Campanelli, M. and Rama, P. (2010) Regional Variation in the Biomechanical Properties of the Human Sclera. Experimental Eye Research, 90, 624-633.

[12]   Silver, F.H. and Shah, R. (2016) Measurement of Mechanical Properties of Natural and Engineered Implants. Advances in Tissue Engineering and Regenerative Medicine, 1, 1-9.

[13]   Yamada, H. and Evans, F.G. (1970) Strength of Biological Materials. University of Michigan.

[14]   Fung, Y.C. (1993) Biomechanics: Mechanical Properties of Living Tissue. 2nd Edition, Springer.

[15]   Dunn, M.G. and Silver, F.H. (1983) Viscoelastic Behavior of Human Connective Tissues: Relative Contribution of Viscous and Elastic Components. Connective Tissue Research, 12, 59-70.

[16]   Shah, R., Pierce, M.C. and Silver, F.H. (2017) A Method for Non-Destructive Mechanical Testing of Tissues and Implants. Journal of Biomedical Materials Research Part A, 105, 15-22.

[17]   Shah, R.G., DeVore, D. and Silver, F.H. (2018) Biomechanical Analysis of Decellularized Dermis and Skin: Initial in Vivo Observations Using Optical Cohesion Tomography and Vibrational Analysis. Journal of Biomedical Materials Research Part A, 106, 1421-1427.

[18]   Papagiannopoulos, G.A. and Hatzigeorgiou, G.D. (2011) On the Use of the Half-Power Bandwidth Method to Estimate Damping in Building Structures. Soil Dynamics and Earthquake Engineering, 31, 1075-1079.

[19]   Elsheikh, A., Alhasso, D. and Rama, P. (2008) Biomechanical Properties of Human and Porcine Corneas. Experimental Eye Research, 86, 783-790.

[20]   Shah, R.G. and Silver, F.H. (2017) Viscoelastic Behavior of Tissues and Implant materials: Estimation of the Elastic Modulus and Viscous Contribution Using Optical Coherence Tomography and Vibrational Analysis. Journal of Biomedical Technology and Research, 3, 105-109.

[21]   Shah, R., DeVore, D. and Pierce, M.G. (2016) Morphomechanics of Dermis—A Method for Non-Destructive Testing of Collagenous Tissues. Skin Research and Technology, 23, 399-406.

[22]   Prabhat, K.P. and Sanaz, A.L. (2007) Ocular Emergencies. American Family Physician, 76, 829-836.

[23]   Silver, F.H. and Silver, L.L. (2017) Gravity, Mechanotransduction and Healing. SM Journal of Biomedical Engineering, 3, 1023.

[24]   Snowhill, P.B. and Silver, F.H. (2005) A Mechanical Model of Porcine Vascular Tissues—Part II: Stress-Strain and Mechanical Properties of Juvenile Porcine Blood Vessels. Cardiovascular Engineering, 5, 157-169.

[25]   Byun, Y., Kim, S., Lazo, M., Choi, M., Kang, M., Lee, J., Yoo, Y., Whang, W. and Joo, C. (2018) Astigmatic Correction by Intrastromal Astigmatic Keratotomy during Femtosecond Laser-Assisted Cataract Surgery: Factors in Outcomes. Journal of Cataract & Refractive Surgery, 44, 202-208.

[26]   Sun, L., Shen, M., Wang, J., Fang, A., Xu, A., Fang, H. and Lu, F. (2009) Recovery of Corneal Hysteresis after Reduction of Intraocular Pressure in Chronic Primary Angle-Closure Glaucoma. American Journal of Ophthalmology, 6, 1061-1066.

[27]   Pensyl, D., Sullivan-Mee, M., Torres-Monte, M., Halverson, K. and Qualls, C. (2012) Combining Corneal Hysteresis with Central Corneal Thickness and Intraocular Pressure for Glaucoma Risk Assessment. Eye (Lond), 10, 1349-1356.

[28]   Zhang, C., Tatham, A.J., Abe, R.Y., Diniz-Filho, A., Zangwill, L.M., Weinreb, R.N. and Medeiros, F.A. (2016) Corneal Hysteresis and Progressive Retinal Nerve Fiber Loss in Glaucoma. American Journal of Ophthalmology, 166, 29-36.

[29]   Medeiros, F.A., Meira-Freitas, D., Lisboa, R., Kuang, T.M., Zangwill, L.M. and Weinreb, R.N. (2013) Corneal Hysteresis as a Risk Factor for Glaucoma Progression: A Prospective Longitudinal Study. Ophthalmology, 8, 1533-1540.

[30]   Park, J.H., Jun, R.M. and Choi, K.R. (2015) Significance of Corneal Biomechanical Properties in Patients with Progressive Normal-Tension Glaucoma. British Journal of Ophthalmology, 6, 746-751.

[31]   Mansouri, K., Leite, M.T., Weinreb, R.N., Tafreshi, A., Zangwill, L.M. and Medeiros, F.A. (2012) Association between Corneal Biomechanical Properties and Glaucoma Severity. American Journal of Ophthalmology, 3, 419-427.

[32]   Vu, D.M., Silva, F.Q., Haseltine, S.J., Ehrlich, J.R. and Radcliffe, N.M. (2013) Relationship between Corneal Hysteresis and Optic Nerve Parameters Measured with Spectral Domain Optical Coherence Tomography. Graefe’s Archive for Clinical and Experimental Ophthalmology, 7, 1777-1783.

[33]   Chang, P.Y. and Chang, S.W. (2013) Corneal Biomechanics, Optic Disc Morphology, and Macular Ganglion Cell Complex in Myopia. Journal of Glaucoma, 22, 358-362.

[34]   Martinez-Abad, A. and Pinero, D.P. (2017) New Perspectives on the Detection and Progression of Keratoconus. Journal of Cataract & Refractive Surgery, 43, 1213-1227.

[35]   Vinciguerra, R., Ambrosio, R., Elsheikh, A., Roberts, C.J., Lopes, B., Morenghi, E., Azzolini, C. and Vinciguerra, P. (2016) Detection of Keratoconus with a New Biomechanical Index. Journal of Refractive Surgery, 12, 803-810.

[36]   Ambrosio, R., Lopes, B.T., Faria-Correia, F., Salomeo, M.Q., Buhren, J., Roberts, C.J., Elsheikh, A., Vinciguerra, R. and Vinciguerra, P. (2017) Integration of Scheimpflug-Based Corneal Topography and Biomechanical Assessments for Enhancing Ectasia Detection. Journal of Refractive Surgery, 7, 434-443.

[37]   Huang, W., Fan, Q., Wang, W., Zhou, M., Laties, A.M. and Zhang, X. (2013) Collagen: A Potential Factor Involved in the Pathogenesis of Glaucoma. Medical Science Monitor Basic Research, 19, 237-240.

[38]   Yamanari, M., Nagase, S., Fukuda, S., Ishii, K., Tanaka, R., Yasui, T., Oshika, T., Miura, M. and Yasuno, Y. (2014) Scleral Birefringence as Measured by Polarization-Sensitive Optical Coherence Tomography and Ocular Biometric Parameters of Human Eyes in Vivo. Optical Society of America, 5, 1391-1402.