A mechanical model of posterior vitreous detachment and generation of vitreoretinal tractions
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ORIGINAL PAPER
A mechanical model of posterior vitreous detachment and generation of vitreoretinal tractions Federica Di Michele1 · Amabile Tatone2 · Mario R. Romano3 · Rodolfo Repetto4 Received: 13 February 2020 / Accepted: 19 June 2020 © Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract We propose a mechanical model of generation of vitreoretinal tractions in the presence of posterior vitreous detachment (PVD). PVD is a common occurrence with aging, and it consists in the separation of the vitreous body from the retina at the back pole of the eye, due to progressive shrinking of the vitreous gel. During this separation process, vitreoretinal tractions are generated at regions of high adhesion between the vitreous and the retina. Such tractions are mainly responsible for the creation of retinal tears, which can lead to retinal detachment. We describe the PVD evolution developing a continuum model of a shrinking soft body, representing the vitreous humor gel phase. In the model, the vitreous is surrounded by a membrane, stiffer than the bulk, the vitreous cortex, and it is contained within a rigid spherical domain, the vitreous chamber. The membrane is attached to the spherical wall and the adhesion strength is spatially non-uniform, increasing from the back to the front of the chamber, according to clinical observations. During the shrinking process, the vitreous undergoes elastic distortions, owing to the spatially variable adhesion on the wall, and this produces boundary tractions. We also consider the clinically relevant case of anomalous PVD, in which regions of focal adhesion between the vitreous and the retina exist, leading to the generation of strong, localized tractions. The model reproduces a PVD evolution in good qualitative agreement with clinical observations and makes it possible to correlate the shape of the detached vitreous with the intensity of vitreoretinal tractions. Keywords Posterior vitreous detachment · Vitreoretinal tractions · Retinal detachment · Vitreous biomechanics
1 Introduction Electronic supplementary material The online version of this article (https://doi.org/10.1007/s10237-020-01360-1) contains supplementary material, which is available to authorized users. * Rodolfo Repetto [email protected] Federica Di Michele [email protected] Amabile Tatone [email protected] Mario R. Romano [email protected] 1
Gran Sasso Science Institute, L’Aquila, Italy
2
Department of Information Engineering, Computer Science and Mathematics, University of L’Aquila, L’Aquila, Italy
3
Department of Biomedical Sciences, Humanitas University, Milan, Italy
4
Department of Civil, Chemical and Environmental Engineering, University of Genoa, Genoa, Italy
The vitreous chamber of the eye is the region located behind the lens and surrounded posteriorly by the retina, see Fig. 1a. It is filled with the vitreous humor, a substance with the consistency of a gel and viscoelastic properties Silva et al. (2017). With aging, the vitreous body is
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