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Suzuki S, Ikeda A, Uemura T, Harada K, Takahashi R, Huang J, Tsukahara-Kawamura T, Ozaki H, Kadonosono K, Uchio E. Simulation of Changes in Tensile Strain by Airbag Impact on Eyes After Trabeculectomy by Using Finite Element Analysis. Clin Ophthalmol 2024; 18:1353-1370. [PMID: 38765458 PMCID: PMC11102099 DOI: 10.2147/opth.s459925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Accepted: 04/24/2024] [Indexed: 05/22/2024] Open
Abstract
Purpose We studied the kinetic phenomenon of an airbag impact on eyes after trabeculectomy using finite element analysis (FEA), a computerized method for predicting how an object reacts to real-world physical effects and showing whether an object will break, to sequentially determine the responses at various airbag deployment velocities. Methods A human eye model was used in the simulations using the FEA program PAM-GENERISTM (Nihon ESI, Tokyo, Japan). A half-thickness incised scleral flap was created on the limbus and the strength of its adhesion to the outer sclera was set at 30%, 50%, and 100%. The airbag was set to hit the surface of the post-trabeculectomy eye at various velocities in two directions: perpendicular to the corneal center or perpendicular to the scleral flap (30° gaze-down position), at initial velocities of 20, 30, 40, 50, and 60 m/s. Results When the airbag impacted at 20 m/s or 30 m/s, the strain on the cornea and sclera did not reach the mechanical threshold and globe rupture was not observed. Scleral flap lacerations were observed at 40 m/s or more in any eye position, and scleral rupture extending posteriorly from the scleral flap edge and rupture of the scleral flap resulting from extension of the corneal laceration through limbal damage were observed. Even in the case of 100% scleral flap adhesion strength, scleral flap rupture occurred at 50 m/s impact velocity in the 30° gaze-down position, whereas in eyes with 30% or 50% scleral flap adhesion strength, scleral rupture was observed at an impact velocity of 40 m/s or more in both eye positions. Conclusion An airbag impact of ≥40 m/s might induce scleral flap rupture, indicating that current airbags may induce globe rupture in the eyes after trabeculectomy. The considerable damage caused by an airbag on the eyes of short-stature patients with glaucoma who have undergone trabeculectomy might indicate the necessity of ocular protection to avoid permanent eye damage.
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Affiliation(s)
- Shuji Suzuki
- Department of Ophthalmology, Fukuoka University School of Medicine, Fukuoka, Japan
| | - Aya Ikeda
- Department of Ophthalmology, Fukuoka University School of Medicine, Fukuoka, Japan
| | - Takashi Uemura
- Department of Ophthalmology, Fukuoka University School of Medicine, Fukuoka, Japan
| | - Kazuhiro Harada
- Department of Ophthalmology, Fukuoka University School of Medicine, Fukuoka, Japan
| | - Rie Takahashi
- Department of Ophthalmology, Fukuoka University School of Medicine, Fukuoka, Japan
| | - Jane Huang
- Department of Ophthalmology, Fukuoka University School of Medicine, Fukuoka, Japan
| | | | - Hiroaki Ozaki
- Department of Ophthalmology, Fukuoka University School of Medicine, Fukuoka, Japan
| | - Kazuaki Kadonosono
- Department of Ophthalmology, Yokohama City University Medical Center, Yokohama, Japan
| | - Eiichi Uchio
- Department of Ophthalmology, Fukuoka University School of Medicine, Fukuoka, Japan
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Ueno T, Fujita H, Ikeda A, Harada K, Tsukahara-Kawamura T, Ozaki H, Uchio E. Finite Element Analysis of Changes in Deformation of Intraocular Segments by Airbag Impact in Eyes of Various Axial Lengths. Clin Ophthalmol 2024; 18:699-712. [PMID: 38468913 PMCID: PMC10926924 DOI: 10.2147/opth.s445253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 02/20/2024] [Indexed: 03/13/2024] Open
Abstract
Background We studied the kinetic phenomenon of an airbag impact on eyes with different axial lengths using finite element analysis (FEA) to sequentially determine the physical and mechanical responses of intraocular segments at various airbag deployment velocities. Methods The human eye model we created was used in simulations with the FEA program PAM-GENERISTM. The airbag was set to impact eyes with axial lengths of 21.85 mm (hyperopia), 23.85 mm (emmetropia) and 25.85 mm (myopia), at initial velocities of 20, 30, 40, 50 and 60 m/s. The deformation rate was calculated as the ratio of the length of three segments, anterior chamber, lens and vitreous, to that at the baseline from 0.2 ms to 2.0 ms after the airbag impact. Results Deformation rate of the anterior chamber was greater than that of other segments, especially in the early phase, 0.2-0.4 ms after the impact (P < 0.001), and it reached its peak, 80%, at 0.8 ms. A higher deformation rate in the anterior chamber was found in hyperopia compared with other axial length eyes in the first half period, 0.2-0.8 ms, followed by the rate in emmetropia (P < 0.001). The lens deformation rate was low, its peak ranging from 40% to 75%, and exceeded that of the anterior chamber at 1.4 ms and 1.6 ms after the impact (P < 0.01). The vitreous deformation rate was lower throughout the simulation period than that of the other segments and ranged from a negative value (elongation) in the later phase. Conclusion Airbag impact on the eyeball causes evident deformation, especially in the anterior chamber. The results obtained in this study, such as the time lag of the peak deformation between the anterior chamber and lens, suggest a clue to the pathophysiological mechanism of airbag ocular injury.
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Affiliation(s)
- Tomohiro Ueno
- Department of Ophthalmology, Fukuoka University School of Medicine, Fukuoka, Japan
| | - Hideaki Fujita
- Department of Ophthalmology, Fukuoka University School of Medicine, Fukuoka, Japan
| | - Aya Ikeda
- Department of Ophthalmology, Fukuoka University School of Medicine, Fukuoka, Japan
| | - Kazuhiro Harada
- Department of Ophthalmology, Fukuoka University School of Medicine, Fukuoka, Japan
| | | | - Hiroaki Ozaki
- Department of Ophthalmology, Fukuoka University School of Medicine, Fukuoka, Japan
| | - Eiichi Uchio
- Department of Ophthalmology, Fukuoka University School of Medicine, Fukuoka, Japan
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Wang S, Li F, Jin S, Zhang Y, Yang N, Zhao J. Biomechanics of open-globe injury: a review. Biomed Eng Online 2023; 22:53. [PMID: 37226242 DOI: 10.1186/s12938-023-01117-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 05/19/2023] [Indexed: 05/26/2023] Open
Abstract
Open-globe injury is a common cause of blindness clinically caused by blunt trauma, sharp injury, or shock waves, characterised by rupture of the cornea or sclera and exposure of eye contents to the environment. It causes catastrophic damage to the globe, resulting in severe visual impairment and psychological trauma to the patient. Depending on the structure of the globe, the biomechanics causing ocular rupture can vary, and trauma to different parts of the globe can cause varying degrees of eye injury. The weak parts or parts of the eyeball in contact with foreign bodies rupture when biomechanics, such as external force, unit area impact energy, corneoscleral stress, and intraocular pressure exceed a certain value. Studying the biomechanics of open-globe injury and its influencing factors can provide a reference for eye-contact operations and the design of eye-protection devices. This review summarises the biomechanics of open-globe injury and the relevant factors.
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Affiliation(s)
- Songtao Wang
- Department of Ophthalmology, The Second Hospital of Jilin University, No. 4026, Yatai Street, Nanguan District, Changchun, Jilin, China
| | - Fuqiang Li
- Department of Ophthalmology, The Second Hospital of Jilin University, No. 4026, Yatai Street, Nanguan District, Changchun, Jilin, China
| | - Siyan Jin
- Department of Ophthalmology, The Second Hospital of Jilin University, No. 4026, Yatai Street, Nanguan District, Changchun, Jilin, China
| | - Yu Zhang
- Department of Ophthalmology, The Second Hospital of Jilin University, No. 4026, Yatai Street, Nanguan District, Changchun, Jilin, China
| | - Ning Yang
- Department of Ophthalmology, The Second Hospital of Jilin University, No. 4026, Yatai Street, Nanguan District, Changchun, Jilin, China
| | - Jinsong Zhao
- Department of Ophthalmology, The Second Hospital of Jilin University, No. 4026, Yatai Street, Nanguan District, Changchun, Jilin, China.
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Kobayashi A, Izaki R, Fujita H, Harada K, Ozaki H, Kadonosono K, Uchio E. Finite element analysis of changes in tensile strain and deformation by airbag impact in eyes of various axial lengths. Int Ophthalmol 2022:10.1007/s10792-022-02609-7. [DOI: 10.1007/s10792-022-02609-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 12/02/2022] [Indexed: 12/24/2022]
Abstract
Abstract
Purpose
Airbags have substantially reduced mortality and morbidity, while ocular injuries caused by airbags have been reported. We applied a three-dimensional finite element analysis (FEA) model we have established for evaluation of the deformation of an intact eyeball of various axial lengths induced by an airbag impact at various impact velocities.
Methods
A model human eye we have created was used in simulations with an FEA program, PAM-GENERIS™ (Nihon ESI, Tokyo, Japan). The airbag was set to impact eyes with various axial lengths of 21.85 mm (hyperopia), 23.85 mm (emmetropia) and 25.85 mm (myopia), at initial velocities of 30, 40, 50 and 60 m/s. Changes in the shape of the eye and the strain induced were calculated. Deformation of the eye in a cross-sectional view was displayed sequentially in slow motion.
Results
We found that considerable damage, such as corneal or scleral lacerations, was observed especially at higher impact velocities, such as 50 or 60 m/s, in eyes with any axial length. Deformation was most evident in the anterior segment. The decrease rate of axial length was greatest in the hyperopic eye, followed by the myopic eye, and the emmetropic eye.
Conclusions
It was shown that hyperopic eyes are most susceptible to deformation by an airbag impact in this simulation. The considerable deformation by an airbag impact on the eye during a traffic accident shown in this study might indicate the necessity of ocular protection to avoid permanent eye damage.
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Foster WJ, Berg BW, Luminais SN, Hadayer A, Schaal S. Computational Modeling of Ophthalmic Procedures: Computational Modeling of Ophthalmic Procedures. Am J Ophthalmol 2022; 241:87-107. [PMID: 35358485 PMCID: PMC9444883 DOI: 10.1016/j.ajo.2022.03.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2021] [Revised: 01/16/2022] [Accepted: 03/17/2022] [Indexed: 11/01/2022]
Abstract
PURPOSE To explore how finite-element calculations can continue to contribute to diverse problems in ophthalmology and vision science, we describe our recent work on modeling the force on the peripheral retina in intravitreal injections and how that force increases with shorter, smaller gauge needles. We also present a calculation that determines the location and stress on a retinal pigment epithelial detachment during an intravitreal injection, the possibility that stress induced by the injection can lead to a tear of the retinal pigment epithelium. BACKGROUND Advanced computational models can provide a critical insight into the underlying physics in many surgical procedures, which may not be intuitive. METHODS The simulations were implemented using COMSOL Multiphysics. We compared the monkey retinal adhesive force of 18 Pa with the results of this study to quantify the maximum retinal stress that occurs during intravitreal injections. CONCLUSIONS Currently used 30-gauge needles produce stress on the retina during intravitreal injections that is only slightly below the limit that can create retinal tears. As retina specialists attempt to use smaller needles, the risk of complications may increase. In addition, we find that during an intravitreal injection, the stress on the retina in a pigment epithelial detachment occurs at the edge of the detachment (found clinically), and the stress is sufficient to tear the retina. These findings may guide physicians in future clinical research. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.
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Affiliation(s)
- William J Foster
- From the Department of Bioengineering (W.J.F.), Lewes Katz School of Medicine (B.W.B., S.N.L.), Temple University, Philadelphia, Pennsylvania, USA; Altasciences, Montréal, Québec, Canada (W.J.F.).
| | - Brian W Berg
- From the Department of Bioengineering (W.J.F.), Lewes Katz School of Medicine (B.W.B., S.N.L.), Temple University, Philadelphia, Pennsylvania, USA
| | - Steven N Luminais
- From the Department of Bioengineering (W.J.F.), Lewes Katz School of Medicine (B.W.B., S.N.L.), Temple University, Philadelphia, Pennsylvania, USA
| | - Amir Hadayer
- Department of Ophthalmology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel (A.H.)
| | - Shlomit Schaal
- Department of Ophthalmology, University of Massachusetts Medical School, Worcester, Massachusetts, USA (S.S.)
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