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Yoon HY, Byun YS, Kim HS, Chung SH. Causes and outcomes of implantable collamer lens explantation in patients with corneal endothelial cell loss. J Cataract Refract Surg 2024; 50:453-459. [PMID: 38270485 DOI: 10.1097/j.jcrs.0000000000001406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 01/13/2024] [Indexed: 01/26/2024]
Abstract
PURPOSE To investigate the correlated factors of corneal endothelial cell density (ECD) loss and ECD change in implantable collamer lens (ICL) explantation patients. SETTING Seoul St. Mary's Hospital, Seoul, South Korea. DESIGN Retrospective analysis. METHODS The study cohort consisted of 93 eyes from 50 patients who underwent ICL explantation. Correlation analysis was performed to assess the ocular parameters associated with ECD loss, while percentage of ECD change (ΔECD%) was monitored up to 6 months postoperatively. Receiver operating characteristic (ROC) curve was used to set cutoff values of ocular parameters to prevent ECD loss after explantation. RESULTS In multiple regression analysis, high vaulting, high vaulting/anterior chamber depth (ACD), low anterior chamber angle (ACA), and high iris pigmentations are the significant factors of ECD loss. At postoperative 6 months, 14 eyes (15.1%) had decrease (10.5% loss), 47 eyes (51.0%) were stationary, and 32 eyes (34.4%) had increase (12.7% gain) of ECD. The ROC curve analysis showed that vaulting had the highest area under the curve (AUC = 0.822), followed by vaulting/ACD (AUC = 0.821), ECD (AUC = 0.753), and ACA (AUC = 0.723) (all P < .01). Preoperative ECD showed a sensitivity of 77.6% and specificity of 86.7% in preventing ECD loss after explantation, with a cutoff value of 1722 cells/mm 2 , as determined by ROC curve analysis. CONCLUSIONS Our study demonstrated that high vaulting is a significant factor in ECD loss among ICL-inserted patients. To prevent continuous ECD loss in ICL patients, close monitoring of ECD and making appropriate decisions regarding explantation may be necessary.
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Affiliation(s)
- Hye Yeon Yoon
- From the Department of Ophthalmology and Visual Science, Seoul St. Mary's Hospital, College of Medicine, Catholic University of Korea, Seoul, South Korea
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Dahaghin A, Salimibani M, Boszczyk A, Jóźwik A, Skrok M, Grasa J, Siedlecki D. Investigation of crystalline lens overshooting: ex vivo experiment and optomechanical simulation results. Front Bioeng Biotechnol 2024; 12:1348774. [PMID: 38655391 PMCID: PMC11035874 DOI: 10.3389/fbioe.2024.1348774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Accepted: 03/12/2024] [Indexed: 04/26/2024] Open
Abstract
Introduction: Crystalline lens overshooting refers to a situation in which the lens momentarily shifts too much from its typical location immediately after stopping the rotational movement of the eye globe. This movement can be observed using an optical technique called Purkinje imaging. Methods: In this work, an experimental setup was designed to reproduce this effect ex vivo using a fresh porcine eye. The sample was rotated 90° around its centroid using a high-velocity rotation stage, and the Purkinje image sequences were recorded, allowing us to quantify the overshooting effect. The numerical part of the study consisted of developing a computational model of the eye, based on the finite element method, that allowed us to understand the biomechanical behavior of the different tissues in this dynamic scenario. A 2D fluid-structure interaction model of the porcine eye globe, considering both the solid parts and humors, was created to reproduce the experimental outcomes. Results: Outputs of the simulation were analyzed using an optical simulation software package to assess whether the mechanical model behaves optically like the real ex vivo eye. The simulation predicted the experimental results by carefully adjusting the mechanical properties of the zonular fibers and the damping factor. Conclusion: This study effectively demonstrates the importance of characterizing the dynamic mechanical properties of the eye tissues to properly comprehend and predict the overshooting effect.
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Affiliation(s)
- Ali Dahaghin
- Department of Optics and Photonics, Wroclaw University of Science and Technology, Wrocław, Poland
| | - Milad Salimibani
- Department of Optics and Photonics, Wroclaw University of Science and Technology, Wrocław, Poland
| | - Agnieszka Boszczyk
- Department of Optics and Photonics, Wroclaw University of Science and Technology, Wrocław, Poland
| | - Agnieszka Jóźwik
- Department of Optics and Photonics, Wroclaw University of Science and Technology, Wrocław, Poland
| | - Marta Skrok
- Department of Optics and Photonics, Wroclaw University of Science and Technology, Wrocław, Poland
| | - Jorge Grasa
- Aragón Institute of Engineering Research (I3A), University of Zaragoza, Zaragoza, Spain
- Centro de Investigación Biomédica en Red en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Zaragoza, Spain
| | - Damian Siedlecki
- Department of Optics and Photonics, Wroclaw University of Science and Technology, Wrocław, Poland
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Basson N, Peng CHS, Geoghegan P, van der Lecq T, Steven D, Williams S, Lim AE, Ho WH. A computational fluid dynamics investigation of endothelial cell damage from glaucoma drainage devices. Sci Rep 2024; 14:3777. [PMID: 38355702 PMCID: PMC10866882 DOI: 10.1038/s41598-023-50491-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2023] [Accepted: 12/20/2023] [Indexed: 02/16/2024] Open
Abstract
Glaucoma drainage devices (GDDs) are prosthetic-treatment devices for treating primary open-angle glaucoma. Despite their effectiveness in reducing intraocular pressures (IOP), endothelial cell damage (ECD) is a commonly known side-effect. There have been different hypotheses regarding the reasons for ECD with one being an induced increase in shear on the corneal wall. A computational fluid dynamics (CFD) model was used to investigate this hypothesis in silico. The Ahmed Glaucoma Valve (AGV) was selected as the subject of this study using an idealised 3D model of the anterior chamber with insertion angles and positions that are commonly used in clinical practice. It was found that a tube-cornea distance of 1.27 mm or greater does not result in a wall shear stress (WSS) above the limit where ECD could occur. Similarly, a tube-cornea angle of 45° or more was shown to be preferable. It was also found that the ECD region has an irregular shape, and the aqueous humour flow fluctuates at certain insertion angles and positions. This study shows that pathological amounts of WSS may occur as a result of certain GDD placements. Hence, it is imperative to consider the associated fluid force interactions when performing the GDD insertion procedure.
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Affiliation(s)
- Nicol Basson
- Department of Thermal & Fluid Engineering, Faculty of Engineering Technology, University of Twente, Enschede, 7522 NB, The Netherlands.
- Mechanical, Industrial & Aeronautical Engineering, Faculty of Engineering & the Built Environment, University of Witwatersrand, Johannesburg, Private Bag 3, Johannesburg, Wits, 2050, South Africa.
| | - Chao-Hong Surachai Peng
- Mechanical, Industrial & Aeronautical Engineering, Faculty of Engineering & the Built Environment, University of Witwatersrand, Johannesburg, Private Bag 3, Johannesburg, Wits, 2050, South Africa
| | - Patrick Geoghegan
- Department of Mechanical, Biomedical and Design Engineering, School of Engineering & Technology, College of Engineering and Physical Sciences, Aston University, Birmingham, B4 7ET, UK
| | - Tshilidzi van der Lecq
- Division of Ophthalmology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - David Steven
- Division of Ophthalmology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Susan Williams
- Division of Ophthalmology, School of Clinical Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - An Eng Lim
- Bioprocessing Technology Institute, Agency for Science, Technology and Research, 20 Biopolis Way, #06-01 Centros, Singapore, 138668, Singapore
- School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore, 639798, Singapore
| | - Wei Hua Ho
- Mechanical, Industrial & Aeronautical Engineering, Faculty of Engineering & the Built Environment, University of Witwatersrand, Johannesburg, Private Bag 3, Johannesburg, Wits, 2050, South Africa.
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Sánchez-Trancón A, Manito SC, Sierra OT, Baptista AM, Serra PM. Influence of anterior chamber depth and vault on anterior chamber angle morphology after phakic posterior chamber intraocular lens implantation. Int Ophthalmol 2024; 44:15. [PMID: 38321260 DOI: 10.1007/s10792-024-02924-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 12/17/2023] [Indexed: 02/08/2024]
Abstract
PURPOSE This study aims to investigate the influence of anterior chamber depth (ACD) and vault on the anterior chamber angle (ACA) morphology in myopic individuals implanted with posterior chamber phakic intraocular lenses. METHODS This retrospective case series involved 231 eyes receiving a 13.2-mm implantable collamer lens (ICL). Preoperative anterior chamber anatomy was assessed using anterior segment optical coherence tomography (AS-OCT) and optical tomography, while postoperative evaluation employed AS-OCT. ACA morphology was characterized pre- and postoperatively through trabecular iris angle (TIA750), ACA distance opening (AOD750) and trabecular iris space area (TISA750). The influence of ACD and vault was examined by categorizing the sample into ACD (shallow, average and deep) and vault (low, optimal and high) groups. RESULTS Preoperative ACA morphology varied based on ACD, with shallower ACDs exhibiting narrower TIA750, smaller AOD750 and TISA750. ICL implantation induced greater ACA narrowing more in the deep ACD group (TIA750 = 20.1 degrees; AOD750 = 0.82 mm and TISA750 = 0.44 mm2) compared to the shallow ACD group (TIA750 = 15.2 degrees; AOD750 = 0.44 mm and TISA750 = 0.21 mm2). Postoperatively, deeper ACDs showed larger ACAs. Increasing vault magnitude led to increased ACA narrowing, with the low vault group exhibiting smaller closure (TIA750 = 14.3 degrees; AOD750 = 0.56 mm and TISA750 = 0.29 mm2) compared to the high vault group (TIA750 = 20.8 degrees; AOD750 = 0.73 mm and TISA750 = 0.36 mm2). The magnitude of ACA narrowing associated with the vault had a consistent effect across different ACD groups. CONCLUSIONS Posterior chamber intraocular lens implantation results in ACA narrowing, the extent of which is contingent upon preoperative anterior chamber and ACA morphology, with additional influence from vault magnitude.
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Affiliation(s)
- Angel Sánchez-Trancón
- Ophthalmology Clinic Vista Sánchez Trancón, Room 15, Calle La Violeta, 06005, Badajoz, Spain
| | - Santiago Cerpa Manito
- Ophthalmology Clinic Vista Sánchez Trancón, Room 15, Calle La Violeta, 06005, Badajoz, Spain
| | - Oscar Torrado Sierra
- Ophthalmology Clinic Vista Sánchez Trancón, Room 15, Calle La Violeta, 06005, Badajoz, Spain
| | | | - Pedro Miguel Serra
- Ophthalmology Clinic Vista Sánchez Trancón, Room 15, Calle La Violeta, 06005, Badajoz, Spain.
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Tan W, Chen Q, Yang R, Wang Z, Zeng Q, Lei X, Jin L, Zhao S. Characteristics and factors associated with the position of the haptic after ICL V4C implantation. J Cataract Refract Surg 2023; 49:416-422. [PMID: 36700941 DOI: 10.1097/j.jcrs.0000000000001134] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2022] [Accepted: 12/31/2022] [Indexed: 01/27/2023]
Abstract
PURPOSE To assess the position of implantable collamer lens (ICL) haptic after ICL V4C implantation using standardized panoramic ultrasound bimicroscopy (UBM), to analyze its characteristics, associated factors, and the relationship with the clinical vault quantitatively. SETTING Hankou Aier Eye Hospital, Wuhan, Hubei, China. DESIGN Cross-sectional study. METHODS 167 subjects (323 eyes) implanted with ICL V4C who had a 3-month follow-up with UBM examination were included in this study. The relative position of ICL to the adjacent structure and ICL haptic-related parameters (the final tip point of ICL haptic [ftICL haptic], measured from the scleral spur to the final tip of the ICL haptic, the posterior of the ICL to ICL haptic [ICL arc], measured from the posterior surface of the ICL to the ICL haptic plane, and the height of the crystalline lens from the ICL haptic (lens arc), measured from the anterior surface of the crystalline lens to the ICL haptic plane and other parameters), were estimated on the UBM image. Eyes were divided into 3 subgroups according to the ftICL haptic (Group 1: ≤0.5 mm; Group 2: 0.5 to 1.0 mm; and Group 3:≥1.0 mm, respectively), and the factors associated with the ICL haptic-related parameters and their impact on the clinical vault were evaluated. RESULTS The haptics could be imaged in the ciliary sulcus, on the ciliary body, and under the ciliary body in 629 (48.7%), 525 (40.6%), and 138 (10.7%) eyes, respectively. The ftICL haptic and the summation of ICL arc and lens arc showed a correlation with the clinical vault ( r = -0.34, P = .00; r = 0.87, P = .00). When the ftICL haptic results were divided into 3 groups, the percentage of eyes that exhibited clinical vault >750 μm were lowest in Group 3. Multivariate regression analysis showed spherical equivalent, white-to-white (WTW), anterior chamber volume (ACV) and iris-ciliary angle (ICA); the difference between the implanted ICL size and horizontal sulcus-to-sulcus (ICL size-STS) were associated with the ftICL haptic. The IOP, WTW, ACV, and the ICL size-STS were significantly associated with ICL arc, while the ICA and lens rise were associated with lens arc. CONCLUSIONS The position of ICL haptic was associated with the clinical vault. Its quantitative evaluation may provide valuable information to help clinicians to select the best ICL size before surgery and understand the formation of clinical vault after surgery.
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Affiliation(s)
- Weina Tan
- From the Tianjin Key Laboratory of Retinal Functions and Diseases, Tianjin Branch of National Clinical Research Center for Ocular Disease, Eye Institute and School of Optometry, Tianjin Medical University Eye Hospital, Tianjin, Tianjin, China (Tan, Yang, Zhao); Aier Eye Hospital of Wuhan University (Wuhan Aier Eye Hospital), Wuhan, Hubei, China (Tan, Chen, Zeng, Lei, Jin); Hankou Aier Eye Hospital, Wuhan, Hubei, China (Tan, Zeng, Lei, Jin); Hongshan Aier Eye Hospital, Wuhan, Hubei, China (Chen); Aier Institute of Refractive Surgery, Guangzhou, Guangdong, China (Wang)
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Characterizing the Aging Process of the Human Eye: Tear Evaporation, Fluid Dynamics, Blood Flow, and Metabolism-Based Comparative Study. BIOMED RESEARCH INTERNATIONAL 2022; 2022:2805402. [PMID: 35372570 PMCID: PMC8970893 DOI: 10.1155/2022/2805402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 03/03/2022] [Accepted: 03/12/2022] [Indexed: 11/18/2022]
Abstract
Eye temperature and intraocular pressure are two measurable parameters that can be monitored as a health index with aging. Deviations from the normal range of intraocular pressure and temperature lead to the formation of many diseases. This study has been carried out to evaluate the relations between the physiological and anatomical changes of the eye with aging using mathematical modeling. 2D computer-aided design of the human eye has been developed for two major groups: 21 to 30 years and 41 to 50 years. The computer simulation has been carried out to determine the effects of physiological changes of tear evaporation, fluid dynamics, blood flow, and metabolism of eye tissues with aging. The simulation has been carried out in the standing and the supine position of a human body. The rate of temperature change is – 0.0075 K per year in the standing position and – 0.007 K per year in the supine position because of the modeled anatomical and physiological effects. All the three simulation parameters of this study, the temperature of the human eye, the intraocular pressure, and the aqueous humor flow velocity, have been compared with the recent practical and simulation-based experiments to validate our results.
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Almorín-Fernández-Vigo I, Sánchez-Guillén I, Fernández-Vigo JI, De-Pablo-Gómez-de-Liaño L, Kudsieh B, Fernández-Vigo JÁ, Macarro-Merino A. Agreement between optical coherence and Scheimpflug tomography: Vault measurements and reproducibility after implantable collamer lens implantation. J Fr Ophtalmol 2021; 44:1370-1380. [PMID: 34330550 DOI: 10.1016/j.jfo.2021.03.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 02/16/2021] [Accepted: 03/15/2021] [Indexed: 11/20/2022]
Abstract
PURPOSE To evaluate the agreement between Scheimpflug tomography (Pentacam, Oculus) and anterior segment optical coherence tomography (AS-OCT, RTVue 100, Optovue) as well as the reproducibility of each technique in assessing the lens-ICL distance (vault) after implantable collamer lens (ICL) implantation. METHODS The vault was measured manually with Scheimpflug tomography and AS-OCT. Intraclass correlation coefficients (ICC) and Bland-Altman plots were used to determine the reproducibility of measurements and the agreement between them. Multivariate regression analysis was performed to identify predictors of differences in vault measurements between devices. RESULTS 80 eyes of 46 ICL patients were analyzed. Mean patient age was 33.8±7.4 years (range, 21 to 51), and 27 (59%) were women. The preoperative spherical equivalent refraction ranged from -26 to 8.5 diopters (D). The mean vault measured by AS-OCT was 558.8±240.2μm (range, 162 - 1220) vs. 430.1±215.3μm (range, 0 to 1070) by Pentacam. AS-OCT yielded vault values, on average, 128.1±64.6μm higher than the Pentacam (range, -22 to 293μm). The ICC values for consistency and absolute agreement were 0.960 and 0.928, respectively. Reproducibility of vault measurements was excellent for both devices (ICC≥0.946). Four parameters-vault, pupil diameter (PD), PD differences between devices, and preoperative spherical equivalent refraction-were significant predictors of differences in vault measurements (adjusted-R2=0.412; P<0.001). CONCLUSIONS Agreement between AS-OCT and Pentacam for vault measurement was good. Vaults were higher when measured by AS-OCT. These differences are clinically relevant, and therefore these devices cannot be used interchangeably to measure vault.
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Affiliation(s)
| | - I Sánchez-Guillén
- Centro Internacional de Oftalmología Avanzada, Badajoz, Spain; Department of ophthalmology, hospital Llerena-Zafra, Badajoz, Spain
| | - J I Fernández-Vigo
- Centro Internacional de Oftalmología Avanzada, Madrid, Spain; Department of ophthalmology, hospital Clínico San Carlos, Madrid, Spain
| | | | - B Kudsieh
- Centro Internacional de Oftalmología Avanzada, Madrid, Spain; Department of ophthalmology, hospital Puerta de Hierro, Madrid, Spain
| | - J Á Fernández-Vigo
- Centro Internacional de Oftalmología Avanzada, Badajoz, Spain; Centro Internacional de Oftalmología Avanzada, Madrid, Spain; School of Medicine, Universidad de Extremadura, Badajoz, Spain
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8
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Axisymmetric Finite Element Modelling of the Human Lens Complex under Cataract Surgery. Symmetry (Basel) 2021. [DOI: 10.3390/sym13040696] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Cataract is a disease opacifying the crystalline, leading to a blurred vision and ultimately to blindness. With an aging population, the incidence of cataract is increasing, as well as the number of treatments. The solution available is its complete removal, followed by an implant of an intraocular lens (IOL). Although the post-operative complications on cataract surgeries have been decreasing in general, the bag-IOL complex dislocation is still an issue, probably being the most serious complication under this procedure. In this work, an axisymmetric Finite Element (FE) modelling strategy of the crystalline complex during the process of accommodation under cataract surgery is proposed. The goal was to understand the influence of biomechanical alterations promoted by the IOL on bag-IOL dislocation after surgery. An increase of force and stress in the zonules was verified in the pseudophakic eye compared to the complete eye, which could explain why zonules break years after surgery, leading to the bag-IOL dislocation. The axisymmetric FE model proposed in this work is innovative in this field, which still lacks detailed research, and can be an important complement for the clinical and biomechanical work on the crystalline complex.
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Jonker SMR, Berendschot TTJM, Saelens IEY, Bauer NJC, Nuijts RMMA. Phakic intraocular lenses: An overview. Indian J Ophthalmol 2020; 68:2779-2796. [PMID: 33229653 PMCID: PMC7856940 DOI: 10.4103/ijo.ijo_2995_20] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Phakic intraocular lenses (pIOLs) are a common solution for the surgical correction of high myopia and myopia in thin corneas. Global trends result in increasing rates of patients with high myopia which will result in increased rates of pIOL implantation. Three types of lenses can be distinguished: anterior chamber angle-supported, anterior chamber iris-fixated, and posterior chamber phakic IOLs. The efficacy of phakic intraocular lenses is generally very good, but pIOLs have undergone many changes over the years to improve the safety profile and decrease pIOL-related complications such as endothelial cell loss, corneal decompensation and cataract formation. This article describes the efficacy and safety profiles of the most recent pIOLs, as well as suggests gaps of knowledge that are deserve additional research to optimize the results of pIOLs.
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Affiliation(s)
- Soraya M R Jonker
- University Eye Clinic Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Tos T J M Berendschot
- University Eye Clinic Maastricht, Maastricht University Medical Center, Maastricht, The Netherlands
| | | | - Noël J C Bauer
- University Eye Clinic Maastricht, Maastricht University Medical Center, Maastricht; Department of Ophthalmology, Zuyderland Medical Center, Heerlen, The Netherlands
| | - Rudy M M A Nuijts
- University Eye Clinic Maastricht, Maastricht University Medical Center, Maastricht; Department of Ophthalmology, Zuyderland Medical Center, Heerlen, The Netherlands
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Numerical model to predict and compare the hypotensive efficacy and safety of minimally invasive glaucoma surgery devices. PLoS One 2020; 15:e0239324. [PMID: 32991588 PMCID: PMC7523982 DOI: 10.1371/journal.pone.0239324] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Accepted: 09/04/2020] [Indexed: 12/25/2022] Open
Abstract
Purpose To predict and compare the hypotensive efficacy of three minimally-invasive glaucoma surgery (MIGS) implants through a numerical model. Methods Post-implant hypotensive efficacy was evaluated by using a numerical model and a computational fluid dynamics simulation. Three different devices were compared: the XEN 45 stent (tube diameter, 45 μm), the XEN 63 stent (63 μm) and the PreserFlo microshunt (70 μm). The influence of the filtration bleb pressure (Bp) and tube diameter, length, and position within the anterior chamber (AC) on intraocular pressure (IOP) were evaluated. Results Using baseline IOPs of 25, 30 and 50 mmHg, respectively, the corresponding computed post-implant IOPs for each device were as follows: XEN 45: 17 mmHg (29% decrease), 19 mmHg (45%) and 20 mmHg (59%) respectively; XEN 63: 13 mmHg (48%), 13 mmHg (62%), and 13 mmHg (73%); PreserFlo: 12 mmHg (59%), 13 mmHg (73%) and 13 mmHg (73%). At a baseline IOP of 35 mmHg with an increase in the outflow resistance within the Bp from 5 to 17 mmHg, the hypotensive efficacy for each device was reduced as follows: XEN45: 54% to 37%; XEN 63: 74% to 46%; and PreserFlo: 75% to 47%. The length and the position of the tube in the AC had only a minimal (non-significant) effect on IOP (<0.1 mmHg). Conclusions This hydrodynamic/numerical model showed that implant diameter and bleb pressure are the two most pertinent determinants of hypotensive efficacy. In distinction, tube length and position in the AC do not significantly influence IOP.
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Martínez-Plaza E, López-Miguel A, Holgueras A, Barraquer RI, Alió JL, Maldonado MJ. Phakic intraocular lenses: Recent advances and innovations. ARCHIVOS DE LA SOCIEDAD ESPANOLA DE OFTALMOLOGIA 2020; 95:178-187. [PMID: 32156485 DOI: 10.1016/j.oftal.2020.02.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 02/02/2020] [Accepted: 02/04/2020] [Indexed: 06/10/2023]
Abstract
Phakic intraocular lenses (pIOL) are recommended when counselling refractive surgery candidates presenting with high ametropia or ocular surface and/or corneal conditions that contraindicate corneal refractive surgery. This review aims to present the state-of-the-art regarding pIOL models currently available in Europe, addressing their newer indications and recent design innovations. These include, in the case of posterior chamber pIOLs, the addition of a central hole to improve aqueous humour circulation, the availability of larger optical zones, and multifocal optics for the compensation of presbyopia. The review also highlights their good safety and efficacy results, as well as the role of patient education to ensure adequate outcomes in the medium-long term. The indications of pIOLs in special situations, as well as bi-lensectomy, a procedure that most pIOL patients may eventually require as they age and develop cataracts, are also addressed.
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Affiliation(s)
- E Martínez-Plaza
- Instituto de Oftalmobiología Aplicada (IOBA), Universidad de Valladolid, Valladolid, España; Red Temática de Investigación Colaborativa en Oftalmología (OftaRed), Instituto de Salud Carlos III, Madrid, España
| | - A López-Miguel
- Instituto de Oftalmobiología Aplicada (IOBA), Universidad de Valladolid, Valladolid, España; Red Temática de Investigación Colaborativa en Oftalmología (OftaRed), Instituto de Salud Carlos III, Madrid, España
| | - A Holgueras
- Instituto de Oftalmobiología Aplicada (IOBA), Universidad de Valladolid, Valladolid, España
| | - R I Barraquer
- Institut Universitari Barraquer, Universitat Autònoma de Barcelona, Universitat Internacional de Catalunya, Barcelona, España; Red Temática de Investigación Colaborativa en Oftalmología (OftaRed), Instituto de Salud Carlos III, Madrid, España
| | - J L Alió
- Vissum Instituto Oftalmológico de Alicante, Alicante, España; Red Temática de Investigación Colaborativa en Oftalmología (OftaRed), Instituto de Salud Carlos III, Madrid, España
| | - M J Maldonado
- Instituto de Oftalmobiología Aplicada (IOBA), Universidad de Valladolid, Valladolid, España; Red Temática de Investigación Colaborativa en Oftalmología (OftaRed), Instituto de Salud Carlos III, Madrid, España.
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Davvalo Khongar P, Pralits JO, Cheng X, Pinsky P, Soleri P, Repetto R. A Mathematical Model of Corneal Metabolism in the Presence of an Iris-Fixated Phakic Intraocular Lens. Invest Ophthalmol Vis Sci 2019; 60:2311-2320. [PMID: 31117123 DOI: 10.1167/iovs.19-26624] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Corneal endothelial cell loss is one of the possible complications associated with phakic iris-fixated intraocular lens (PIOL) implantation. We postulate that this might be connected to the alteration of corneal metabolism secondary to the lens implantation. Methods A mathematical model of transport and consumption/production of metabolic species in the cornea is proposed, coupled with a model of aqueous flow and transport of metabolic species in the anterior chamber. Results Results are presented both for open and closed eyelids. We showed that, in the presence of a PIOL, glucose availability at the corneal endothelium decreases significantly during sleeping. Conclusions Implantation of a PIOL significantly affects nutrient transport processes to the corneal endothelium especially during sleep. It must still be verified whether this finding has a clinical relevance.
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Affiliation(s)
- Peyman Davvalo Khongar
- Department of Civil, Chemical and Environmental Engineering, University of Genoa, Genoa, Italy
| | - Jan O Pralits
- Department of Civil, Chemical and Environmental Engineering, University of Genoa, Genoa, Italy
| | - Xi Cheng
- Mechanical Engineering, Stanford University, Stanford, California, United States
| | - Peter Pinsky
- Mechanical Engineering, Stanford University, Stanford, California, United States
| | | | - Rodolfo Repetto
- Department of Civil, Chemical and Environmental Engineering, University of Genoa, Genoa, Italy
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Agujetas R, Marcos AC, Fernández-Vigo JI, Montanero JM. Influence of an iris-fixed phakic intraocular lens on the transport of nutrients by the aqueous humor. Biomech Model Mechanobiol 2018; 18:491-502. [DOI: 10.1007/s10237-018-1099-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 11/18/2018] [Indexed: 11/28/2022]
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Abstract
The purpose of this review is to summarize preclinical and clinical data from publications appearing in the peer-reviewed scientific literature relevant to the safety and effectiveness of the EVO Implantable Collamer Lens (ICL) posterior chamber phakic refractive lens with a central port (V4c Visian ICL with KS Aquaport, STAAR Surgical, Inc.). A literature search was conducted using PubMed.gov to identify all articles relating to the EVO ICL. Articles were examined for their relevance, and the references cited in each article were also searched for additional relevant publications. On the basis of a total of 67 preclinical studies and clinical reports, including effectiveness data on 1,905 eyes with average weighted follow-up of 12.5 months and safety data on 4,196 eyes with weighted average follow up of 14.0 months, the EVO ICL is safe and effective for the correction of a broad range of refractive errors. High levels of postoperative uncorrected visual acuity, refractive predictability, and stability demonstrate the effectiveness of the EVO ICL. Safety data suggest reduced rates of anterior subcapsular cataract and pupillary block compared with earlier models. Improved safety and proven effectiveness make EVO an attractive option for surgeons and patients.
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Affiliation(s)
- Mark Packer
- Mark Packer MD Consulting, Inc., Boulder, CO, USA,
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