Abstract
Purpose :
To enhance the existing SyntEyes model by integrating the material properties of the tissues, enabling comprehensive opto-biomechanical (OBM) analyses for a realistic range of ocular biometry.
Methods :
Based on SyntEyes a 3-D eye model was developed, including the cornea, sclera, lens, ciliary body, and zonular fibers. The anterior and posterior surfaces of the cornea are characterized by 45 Zernike coefficients over a 6.5 mm diameter, connected to a limbus of 11 mm diameter through a smooth biconic surface. Meanwhile, the crystalline lens is modelled as two aspherical surfaces and the sclera as a thick spherical shell with a uniform thickness of 0.83 mm. The ciliary body is 4.6 mm long and 0.72 mm wide at the apex, from which 5 sets of zonular fibers (modeled as thin sheets) connect to the lens. To generate the mesh, each eye component is triangulated and exported for further customization (e.g., to increase the mesh size). This mesh is then imported into ANSYS to analyze the biomechanical properties of the eye for an intraocular pressure of 16mmHg, thus finalizing the OBM SyntEyes. To illustrate a possible use case, the anterior corneal surface of 10 SyntEyes was reshaped to simulate photorefractive keratotomy (PRK) for myopia to assess the changes in stress and corneal displacement.
Results :
The SyntEyes had on average 420,125 nodes and 302,254 elements (Figure 1). Simulating the PRK procedure to correct for on average -3.70 ± 2.28D of myopia targeting emmetropia, locally increased the equivalent stress by 0.013± 0.001 MPa and shifted the cornea forward on average by 0.0769 ± 0.023 mm (Figure 2). This is line with a previous paper on the topic (Yinyu Song, EDP Sciences, 2021).
Conclusions :
This work introduces a biomechanical dimension to the existing SyntEyes model. The integration of biomechanical features into the established optical framework enables simultaneous and precise evaluation of the eye's optical and biomechanical properties. This enhancement potentially makes the model an invaluable asset for both optical and clinical simulations, offering a more holistic and accurate approach to eye care research and practice.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.