1
|
Correlation study of biomechanical changes between diabetic eye disease and glaucoma using finite element model of human eye with different iris-lens channel distances. Med Eng Phys 2022; 109:103910. [DOI: 10.1016/j.medengphy.2022.103910] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 10/08/2022] [Accepted: 10/16/2022] [Indexed: 11/06/2022]
|
2
|
Basson N, Alimahomed F, Geoghegan PH, Williams SE, Ho WH. An aqueous humour fluid dynamic study for normal and glaucomatous eye conditions. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2022; 2022:3963-3966. [PMID: 36086118 DOI: 10.1109/embc48229.2022.9871009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Glaucoma is the leading cause of irreversible blindness worldwide. Currently, the only treatable risk factor for glaucoma is elevated intraocular pressure (IOP). Glaucoma is commonly caused due to a decreased permeability of the trabecular meshwork, a porous structure at the eye outlet. This prevents the effective outflow of aqueous humour, increasing IOP. This study aims to simulate both normal and glaucomatous conditions of aqueous humour flow in the eye via computational fluid dynamics (CFD). Using clinical data, an idealised geometrical model of the eye was created. Darcy's law was employed to calculate the permeability values for various IOPs, which was then applied to the CFD model. Subsequently, verifiable and validated models for a normal and glaucomatous eye were achieved. Clinical Relevance- Glaucoma surgical treatments are often met with post-operative complications due to an insufficient or even excessive outflow of aqueous humour. The resulting glaucomatous eye model from this study can be used to test how different glaucoma filtration surgeries affect the efficacy of aqueous humour outflow. In turn, the most effective glaucoma surgical procedure may be identified for specific eye geometries according to race, age, gender, etc.
Collapse
|
3
|
Ocular Fluid Mechanics and Drug Delivery: A Review of Mathematical and Computational Models. Pharm Res 2021; 38:2003-2033. [PMID: 34936067 DOI: 10.1007/s11095-021-03141-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 11/10/2021] [Indexed: 10/19/2022]
Abstract
The human eye is a complex biomechanical structure with a range of biomechanical processes involved in various physiological as well as pathological conditions. Fluid flow inside different domains of the eye is one of the most significant biomechanical processes that tend to perform a wide variety of functions and when combined with other biophysical processes play a crucial role in ocular drug delivery. However, it is quite difficult to comprehend the effect of these processes on drug transport and associated treatment experimentally because of ethical constraints and economic feasibility. Computational modeling on the other hand is an excellent means to understand the associated complexity between these aforementioned processes and drug delivery. A wide range of computational models specific to different types of fluids present in different domains of the eye as well as varying drug delivery modes has been established to understand the fluid flow behavior and drug transport phenomenon in an insilico manner. These computational models have been used as a non-invasive tool to aid ophthalmologists in identifying the challenges associated with a particular drug delivery mode while treating particular eye diseases and to advance the understanding of the biomechanical behavior of the eye. In this regard, the author attempts to summarize the existing computational and mathematical approaches proposed in the last two decades for understanding the fluid mechanics and drug transport associated with different domains of the eye, together with their application to modify the existing treatment processes.
Collapse
|
4
|
Lamont HC, Masood I, Grover LM, El Haj AJ, Hill LJ. Fundamental Biomaterial Considerations in the Development of a 3D Model Representative of Primary Open Angle Glaucoma. Bioengineering (Basel) 2021; 8:bioengineering8110147. [PMID: 34821713 PMCID: PMC8615171 DOI: 10.3390/bioengineering8110147] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 10/15/2021] [Accepted: 10/17/2021] [Indexed: 12/12/2022] Open
Abstract
Glaucoma is a leading cause of irreversible blindness globally, with primary open angle glaucoma (POAG) being the most common subset. Raised intraocular pressure is an important risk factor for POAG and is caused by a reduction in aqueous humour (AqH) outflow due to dysfunctional cellular and matrix dynamics in the eye’s main drainage site, the trabecular meshwork (TM) and Schlemm’s canal (SC). The TM/SC are highly specialised tissues that regulate AqH outflow; however, their exact mechanisms of AqH outflow control are still not fully understood. Emulating physiologically relevant 3D TM/S in vitro models poses challenges to accurately mimic the complex biophysical and biochemical cues that take place in healthy and glaucomatous TM/SC in vivo. With development of such models still in its infancy, there is a clear need for more well-defined approaches that will accurately contrast the two central regions that become dysfunctional in POAG; the juxtacanalicular tissue (JCT) region of the TM and inner wall endothelia of the Schlemm’s canal (eSC). This review will discuss the unique biological and biomechanical characteristics that are thought to influence AqH outflow and POAG progression. Further consideration into fundamental biomaterial attributes for the formation of a biomimetic POAG/AqH outflow model will also be explored for future success in pre-clinical drug discovery and disease translation.
Collapse
Affiliation(s)
- Hannah C. Lamont
- School of Biomedical Sciences, Institute of Clinical Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK; (H.C.L.); (I.M.)
- School of Chemical Engineering, Healthcare Technologies Institute, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK; (L.M.G.); (A.J.E.H.)
| | - Imran Masood
- School of Biomedical Sciences, Institute of Clinical Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK; (H.C.L.); (I.M.)
| | - Liam M. Grover
- School of Chemical Engineering, Healthcare Technologies Institute, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK; (L.M.G.); (A.J.E.H.)
| | - Alicia J. El Haj
- School of Chemical Engineering, Healthcare Technologies Institute, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK; (L.M.G.); (A.J.E.H.)
| | - Lisa J. Hill
- School of Biomedical Sciences, Institute of Clinical Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK; (H.C.L.); (I.M.)
- Correspondence:
| |
Collapse
|
5
|
Goles N, Nerancic M, Konjik S, Pajic-Eggspuehler B, Pajic B, Cvejic Z. Phacoemulsification and IOL-Implantation without Using Viscoelastics: Combined Modeling of Thermo Fluid Dynamics, Clinical Outcomes, and Endothelial Cell Density. SENSORS 2021; 21:s21072399. [PMID: 33808502 PMCID: PMC8037460 DOI: 10.3390/s21072399] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/13/2021] [Accepted: 03/19/2021] [Indexed: 11/16/2022]
Abstract
Phacoemulsification is a widely used surgical method in cataract surgery with a high energy ultrasound source. The viscoelastic is considered to be tissue protective. The aim of this study is to investigate during surgery the impact of using viscoelastic versus no viscoelastic on clinical outcomes, potential complications and effect on endothelial cell density. The study group included 64 patients, who were subjected to phacoemulsification using balanced salt solution (BSS). Control group consisted of 62 patients, who underwent phacoemulsification using Hyaloronic acid 1% Healon 1%. Student’s t-test was applied for statistical analysis. The simulations of temperature changes during phacoemulsification were performed by COMSOL Multiphysics software. In the BSS group, a mean endothelial cell loss (ECL) of 4.5% was measured one month postoperatively, while in the Healon group ECL was 5.3%. Data analysis showed no significant difference in ECL between the groups (Student’s t-test, p = 0.8). No significant difference was observed in endothelial cell morphology and IOP between the two groups pre- and postoperatively (all p > 0.05). The modeling of thermo fluid dynamics showed that the heating of the cornea is slightly less when Healon was used as irrigation fluid. The phacoemulsification technique can be performed by an experienced surgeon with viscoelastics or continuous anterior chamber (AC) irrigation on the same level of safety regarding endothelial cell damage, providing equally satisfying clinical outcomes.
Collapse
Affiliation(s)
- Nikola Goles
- Department of Physics, Faculty of Sciences, University of Novi Sad, 21000 Novi Sad, Serbia; (N.G.); (M.N.); (B.P.)
| | - Marko Nerancic
- Department of Physics, Faculty of Sciences, University of Novi Sad, 21000 Novi Sad, Serbia; (N.G.); (M.N.); (B.P.)
| | - Sanja Konjik
- Department of Mathematics and Informatics, Faculty of Sciences, University of Novi Sad, 21000 Novi Sad, Serbia;
| | | | - Bojan Pajic
- Department of Physics, Faculty of Sciences, University of Novi Sad, 21000 Novi Sad, Serbia; (N.G.); (M.N.); (B.P.)
- Eye Clinic Orasis, Swiss Eye Research Foundation, 5734 Reinach AG, Switzerland;
- Division of Ophthalmology, Department of Clinical Neurosciences, Geneva University Hospitals, 1205 Geneva, Switzerland
- Faculty of Medicine, University of Geneva, 1211 Geneva, Switzerland
- Faculty of Medicine of the Military Medical Academy, University of Defense, 11000 Belgrade, Serbia
| | - Zeljka Cvejic
- Department of Physics, Faculty of Sciences, University of Novi Sad, 21000 Novi Sad, Serbia; (N.G.); (M.N.); (B.P.)
- Correspondence:
| |
Collapse
|
6
|
Guo JM, Chen ZQ, Chen W, Yan XQ, Zhang H, Wang JM. Numerical simulation of the flow of aqueous humor in the Schlemm's canal. Med Eng Phys 2021; 88:25-31. [PMID: 33485510 DOI: 10.1016/j.medengphy.2020.12.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Revised: 12/09/2020] [Accepted: 12/17/2020] [Indexed: 11/24/2022]
Abstract
Schlemm's canal (SC) is a ring structure responsible for maintaining fluid homeostasis in the anterior chamber of the eye by draining aqueous humor (AH) from the trabecular meshwork (TM) into the collecting channel (CC). Obstruction of the AH flow in this conventional pathway leads to an elevation of intraocular pressure in glaucoma, which is internationally recognized as the most common cause of blindness. Although there are obvious morphological differences between patients and healthy individuals, the AH drainage capacity of SC with specific parameters is difficult to quantitatively evaluate due to the limitations of analyses or experimental technologies. In this paper, the AH flow dynamic features under various SC morphological parameters are studied by numerical simulations of 3D models. The axis length of the SC cross-section and the level of openness are chosen as the main morphological factors according to the clinical data. The flow features, including the velocity, streamline and wall shear stress, are analyzed. This study aimed not only to explore the feasibility of 3D numerical modeling in evaluating the SC drainage capacity, but also to reveal the relationship between SC morphological parameters and the dynamic features of AH drainage.
Collapse
Affiliation(s)
- Jing-Min Guo
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, C.P. 430030, Wuhan, China
| | - Zhi-Qi Chen
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, C.P. 430030, Wuhan, China
| | - Wei Chen
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, C.P. 430030, Wuhan, China
| | - Xiao-Qin Yan
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, C.P. 430030, Wuhan, China
| | - Hong Zhang
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, C.P. 430030, Wuhan, China
| | - Jun-Ming Wang
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, C.P. 430030, Wuhan, China.
| |
Collapse
|
7
|
A novel numerical modelling approach for keratoplasty eye procedure. Biomech Model Mechanobiol 2019; 18:1429-1442. [PMID: 31079255 DOI: 10.1007/s10237-019-01156-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 04/20/2019] [Indexed: 02/03/2023]
Abstract
Objective of the work is to investigate stress and deformation that conrneal tissue and donor graft undergo during endothelial keratoplasty. In order to attach the donor graft to the cornea, different air bubble pressure profiles acting on the graft are considered. This study is carried out by employing a three-dimensional nonlinear finite element methodology, combined with a contact algorithm. The ocular tissues are treated as isotropic, hyper-elastic and nearly-incompressible materials. The contact algorithm, based on the penalty-based node-to-surface approach, is used to model the donor graft-corneal interface region. First, the proposed computational methodology is tested against benchmark data for bending of the plates over a cylinder. Then, the influence of geometrical and material parameters of the graft on the corneal contact-structural response is investigated. The results are presented in terms of Von Mises stress intensity, displacement and mean contact force. Results clearly indicate that the air bubble pressure plays a key role in the corneal stress and strain, as well as graft stiffness and thickness.
Collapse
|
8
|
Mauro A, Massarotti N, Mohamed S, Uña IR, Romano MR, Romano V. A novel patient-oriented numerical procedure for glaucoma drainage devices. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2018; 34:e3141. [PMID: 30101520 DOI: 10.1002/cnm.3141] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 07/30/2018] [Accepted: 08/02/2018] [Indexed: 06/08/2023]
Abstract
The present work analyses the performance of four glaucoma drainage devices, by means of a novel patient-oriented numerical procedure. The procedure is based on the three-dimensional geometry reconstruction from the stacks of tomographic images of a human eye, at different angles, on meshing and on thermo-fluid dynamics modelling activities, carried out on the reconstructed computational domain. The current three-dimensional eye model considers anterior chamber (AC), trabecular meshwork, Schlemm's canal, and collector channels, making use of generalised porous medium approach for modelling ocular porous tissue and cavities. The intraocular pressure (IOP) management inside AC of human eye is analysed, by comparing the results obtained for four drainage devices implanted in a human eye for glaucoma treatment, ie, ExPRESS shunt, iStent inject, SOLX gold micro shunt, and the novel silicon shunt device. The numerical results allow predicting the effects of the installation of these implants on human eyes, in terms of IOP decrease, aqueous humour velocity, pressure, friction coefficient, and local Nusselt number, pointing out the clear distinction between pre-operative and post-operative eye conditions for different glaucoma surgical techniques.
Collapse
Affiliation(s)
- Alessandro Mauro
- Dipartimento di Ingegneria, Università degli Studi di Napoli "Parthenope", Naples, Italy
| | - Nicola Massarotti
- Dipartimento di Ingegneria, Università degli Studi di Napoli "Parthenope", Naples, Italy
| | - Salahudeen Mohamed
- Dipartimento di Ingegneria, Università degli Studi di Napoli "Parthenope", Naples, Italy
| | - Ignacio Rodríguez Uña
- Department of Ophthalmology and Visual Sciences, Queen's Medical Centre, Nottingham University Hospitals NHS Trust, Nottingham, UK
| | - Mario R Romano
- Department of Biomedical Sciences, Humanitas University, Milan, Italy
| | - Vito Romano
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, UK
- Moorfields Eye Hospital, London, UK
| |
Collapse
|