title: Gaussian process prediction of the stress-free configuration of pre-deformed soft tissues: Application to the human cornea.
abstract: Image-based modeling is a popular approach to perform patient-specific biomechanical simulations. One constraint of this technique is that the shape of soft tissues acquired in-vivo is deformed by the physiological loads. Accurate simulations require determining the existing stress in the tissues or their stress-free configurations. This process is time consuming, which is a limitation to the dissemination of numerical planning solutions to clinical practice. In this study, we propose a method to determine the stress-free configuration of soft tissues using a Gaussian process (GP) regression. The prediction relies on a database of pre-calculated results to enable real time predictions. The application of this technique to the human cornea showed a level of accuracy five to ten times higher than the accuracy of the topographic device used to obtain the patients' anatomy; results showed that for almost all optical indices, the predicted curvature error did not exceed 0.025 D, while the wavefront aberration percentage error did not overcome 5%. In this context, we believe that GP models are suitable for predicting the stress free configuration of the cornea and can be used in planning tools based on patient-specific finite element simulations. Due to the high level of accuracy required in ophthalmology, this approach is likely to be appropriate for other applications requiring the definition of the relaxed shape of soft tissues.
authors.affiliation: Institute for Surgical Technology & Biomechanics, University of Bern, Stauffacherstrasse 78, 3014 Bern, Switzerland; Integrated Scientific Services AG, Biel, Switzerland.
authors.forename: Elena
authors.initials: E
authors.lastname: Businaro
authors.affiliation: Integrated Scientific Services AG, Biel, Switzerland.
authors.forename: Harald
authors.initials: H
authors.lastname: Studer
authors.affiliation: Swiss Eye Research Foundation, Eye Clinic ORASIS, Reinach AG, Switzerland; Division of Ophthalmology, Department of Clinical Neurosciences, University Hospitals of Geneva, Switzerland; University of Novi Sad, Faculty of Sciences, Faculty of Physics, Novi Sad, Serbia; Medical faculty, Military Medical Academy, University of Defense, Belgrade, Serbia.
authors.forename: Bojan
authors.initials: B
authors.lastname: Pajic
authors.affiliation: Institute for Surgical Technology & Biomechanics, University of Bern, Stauffacherstrasse 78, 3014 Bern, Switzerland. Electronic address: philippe.buechler@istb.unibe.ch.
authors.forename: Philippe
authors.initials: P
authors.lastname: Büchler
mesh_terms: D001696:Biomechanical Phenomena; D003315:Cornea / Q000166:cytology / Q000601:surgery; D020342:Finite Element Analysis; D006801:Humans; D055595:Mechanical Phenomena; D016011:Normal Distribution; D054140:Refractive Surgical Procedures
keywords: Biomechanics; Cornea; Finite-element; Gaussian process; Prediction; Stress-free