title: Automatized Patient-Specific Methodology for Numerical Determination of Biomechanical Corneal Response.
abstract: This work presents a novel methodology for building a three-dimensional patient-specific eyeball model suitable for performing a fully automatic finite element (FE) analysis of the corneal biomechanics. The reconstruction algorithm fits and smooths the patient's corneal surfaces obtained in clinic with corneal topographers and creates an FE mesh for the simulation. The patient's corneal elevation and pachymetry data is kept where available, to account for all corneal geometric features (central corneal thickness-CCT and curvature). Subsequently, an iterative free-stress algorithm including a fiber's pull-back is applied to incorporate the pre-stress field to the model. A convergence analysis of the mesh and a sensitivity analysis of the parameters involved in the numerical response is also addressed to determine the most influential features of the FE model. As a final step, the methodology is applied on the simulation of a general non-commercial non-contact tonometry diagnostic test over a large set of 130 patients-53 healthy, 63 keratoconic (KTC) and 14 post-LASIK surgery eyes. Results show the influence of the CCT, intraocular pressure (IOP) and fibers (87%) on the numerical corneal displacement (U(Num)) the good agreement of the U(Num) with clinical results, and the importance of considering the corneal pre-stress in the FE analysis. The potential and flexibility of the methodology can help improve understanding of the eye biomechanics, to help to plan surgeries, or to interpret the results of new diagnosis tools (i.e., non-contact tonometers).
authors: Applied Mechanics and Bioengineering (AMB), Aragón Institute of Engineering Research (I3A), University of Zaragoza, Zaragoza, Spain. mariza@unizar.es.
authors: M Á
authors: http://orcid.org/0000-0002-6773-6667
authors: MÁ
authors: Ariza-Gracia
authors: Department of Mechanical Engineering, Energetics and Materials, Public University of Navarra, Pamplona, Spain.
authors: J
authors: J
authors: Zurita
authors: Ophthalmology Department (OFTALMAR), Medimar International Hospital, Alicante, Spain.|Optics, Pharmacologist and Anatomy Department, University of Alicante, Alicante, Spain.
authors: D P
authors: DP
authors: Piñero
authors: Applied Mechanics and Bioengineering (AMB), Aragón Institute of Engineering Research (I3A), University of Zaragoza, Zaragoza, Spain.|Bioengineering, Biomaterials and Nanomedicine Online, Biomedical Research Center (CIBBER-BBN), Madrid, Spain.
authors: B
authors: B
authors: Calvo
authors: Applied Mechanics and Bioengineering (AMB), Aragón Institute of Engineering Research (I3A), University of Zaragoza, Zaragoza, Spain.|LaBS, Department of Chemistry, Materials and Chemical Engineering 'Giulio Natta', Politecnico di Milano, Milano, Italy.
authors: J F
authors: JF
authors: Rodríguez-Matas
mesh_terms: D003315:Cornea / Q000000981:diagnostic imaging* / Q000503:physiopathology* / Q000601:surgery; D063171:Corneal Pachymetry / Q000379:methods*; D019781:Corneal Topography / Q000379:methods*; D005260:Female; D020342:Finite Element Analysis; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D020731:Keratomileusis, Laser In Situ; D008297:Male
keywords: FEM corneal model; Non-contact tonometry; Patient-specific; Sensitivity analysis