A Deeper Look at the Eye: A Microstructure-Based Study of Ocular Tissue
Authors: Zhou, D., Abass, A., Eliasy, A., Studer, H.P., Movchan, A., Movchan, N. and Elsheikh, A.
Journal: Journal of the Royal Society Interface
Publication Date: May 2019
A schematic of fibril recruitment. (a) The global coordinate system was defined by (X, Y, Z), a general integration point was located by the spherical coordinates (r, α, φ), and the normal vector was calculated by two vectors v1 and v2 for each element. (b) Two orthogonal vectors are located on the tangent plane with the unit vector e1 aligned in the meridional tangent direction. The two unit vectors e1, e2 form the local coordinate system together with the normal vector n. The in-plane fibril family, represented by a0, has the discretized orientation defined by azimuthal angle θi. The out-of-plane fibril family, represented by b0, has an orientation defined by θi and an out-of-plane rotation angle 15°. (Online version in colour.)
Summary:
Our eyes are complex and sensitive organs, and understanding their biomechanics is essential for improving medical and surgical procedures involving the eye. In our recent study, we developed a full-eye biomechanical model that considers the microstructure of ocular tissues. This model helps us understand how age-related changes in these tissues affect their mechanical behavior.
We focused on collagen, the main load-carrying component in ocular tissues, and used X-ray scattering measurements to map the collagen fibril magnitude and orientation in the eye. We then built fine-mesh finite-element models to analyze the mechanical behavior of eye tissues from donors aged between 50 and 90 years.
Our analysis demonstrated a steady increase in mechanical stiffness in all ocular regions with age. This finding is important because it allows for more accurate representation of the biomechanical behavior of ocular tissues, which is crucial for planning surgical and medical procedures involving the eye.
One significant aspect of our study was extending previous microstructure-based models to cover the entire ocular globe, not just the cornea or posterior sclera. We also directly linked our modeling process to raw X-ray scattering data, which allowed for a more realistic representation of the regional variation in collagen fibril density and arrangement.
Overall, our study advances our understanding of the biomechanics of the eye by incorporating microstructure data into a full-eye model. This research has the potential to improve surgical and medical procedures by providing more accurate information on ocular tissue behavior, ultimately benefiting patients and medical professionals alike.