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De Francesco T, Armstrong JJ, Hussein IM, Costa VP, Ahmed IIK. Mitomycin C 0.2 mg/ml vs. Mitomycin C 0.4mg/ml during the implantation of an ab externo SIBS microshunt: A mega-analysis. Ophthalmol Glaucoma 2024:S2589-4196(24)00085-1. [PMID: 38851392 DOI: 10.1016/j.ogla.2024.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Revised: 05/18/2024] [Accepted: 06/03/2024] [Indexed: 06/10/2024]
Abstract
PURPOSE To compare the effectiveness and adverse event profile of standalone SIBS microshunt implantation with adjunct MMC 0.2 mg/ml and MMC 0.4 mg/ml. DESIGN Mega-analysis using individual patient data from international prospective and retrospective clinical studies. STUDY POPULATION Patients with glaucoma who underwent implantation of a SIBS microshunt with MMC as a standalone procedure. METHODS A comparison of eyes that received MMC 0.2 mg/ml or 0.4 mg/ml MAIN OUTCOMES MEASURES: Primary outcome was complete success defined as the proportion of eyes at one year with all of the following: (1) no two consecutive IOPs > 17 mmHg; (2) no clinical hypotony (3) ≥20% IOP reduction from baseline and (4) no use of glaucoma medications. Secondary outcomes included IOP thresholds of 12 mmHg,14 mm Hg and 21mmHg, median IOP, number of medications, risk factors for failure, interventions, adverse events, and reoperations. RESULTS At 1 year, the complete success rate was significantly higher (71.3% vs 50.46%, p<0.001) and the median IOP significantly lower (13.0 vs. 14.2 mmHg, p<0.05) in the MMC 0.4 mg/ml group. MMC 0.2 mg/ml was found to be a significant risk factor for failure (HR 1.75 95%CI 1.14 to 2.67). Needling and surgical revision occurred at a lower rate in the MMC 0.4 mg/ml group (7% vs. 18.8%, p= 0.002 and 4.3% vs.13.7% p= 0.0087, respectively). Adverse events occurred at a similar frequency in both groups (26.6% MMC 0.2 mg/ml vs. 29.6% MMC 0.4 mg/ml, p=0.46), most of which were early and transient. CONCLUSION SIBS microshunt implantation with MMC 0.4 mg/ml resulted in a higher success rate with greater IOP reduction compared to MMC 0.2 mg/ml. Higher MMC concentration was not associated with increased serious adverse events.
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Affiliation(s)
- Ticiana De Francesco
- John A. Moran Eye Center, University of Utah, Salt Lake City, USA; University of Campinas, Campinas, Brazil; Clinica de Olhos De Francesco, Fortaleza, Brazil; Hospital de Olhos Leiria de Andrade, Fortaleza, Brazil.
| | - James J Armstrong
- Department of Ophthalmology, Schulich School of Medicine, Western University, London, Canada
| | - Isra M Hussein
- Department of Ophthalmology and Visual Sciences, Dalhousie University, Halifax, Canada
| | | | - Iqbal Ike K Ahmed
- John A. Moran Eye Center, University of Utah, Salt Lake City, USA; Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Canada; Prism Eye Institute, Mississauga, Canada
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2
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Trask L, Ward NA, Tarpey R, Beatty R, Wallace E, O'Dwyer J, Ronan W, Duffy GP, Dolan EB. Exploring therapy transport from implantable medical devices using experimentally informed computational methods. Biomater Sci 2024; 12:2899-2913. [PMID: 38683198 DOI: 10.1039/d4bm00107a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2024]
Abstract
Implantable medical devices that can facilitate therapy transport to localized sites are being developed for a number of diverse applications, including the treatment of diseases such as diabetes and cancer, and tissue regeneration after myocardial infraction. These implants can take the form of an encapsulation device which encases therapy in the form of drugs, proteins, cells, and bioactive agents, in semi-permeable membranes. Such implants have shown some success but the nature of these devices pose a barrier to the diffusion of vital factors, which is further exacerbated upon implantation due to the foreign body response (FBR). The FBR results in the formation of a dense hypo-permeable fibrous capsule around devices and is a leading cause of failure in many implantable technologies. One potential method for overcoming this diffusion barrier and enhancing therapy transport from the device is to incorporate local fluid flow. In this work, we used experimentally informed inputs to characterize the change in the fibrous capsule over time and quantified how this impacts therapy release from a device using computational methods. Insulin was used as a representative therapy as encapsulation devices for Type 1 diabetes are among the most-well characterised. We then explored how local fluid flow may be used to counteract these diffusion barriers, as well as how a more practical pulsatile flow regimen could be implemented to achieve similar results to continuous fluid flow. The generated model is a versatile tool toward informing future device design through its ability to capture the expected decrease in insulin release over time resulting from the FBR and investigate potential methods to overcome these effects.
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Affiliation(s)
- Lesley Trask
- Biomedical Engineering, School of Engineering, University of Galway, Galway, Ireland
- Biomechanics Research Centre (BMEC), Biomedical Engineering, School of Engineering, University of Galway, Galway, Ireland
| | - Niamh A Ward
- Biomedical Engineering, School of Engineering, University of Galway, Galway, Ireland
- Biomechanics Research Centre (BMEC), Biomedical Engineering, School of Engineering, University of Galway, Galway, Ireland
| | - Ruth Tarpey
- Biomedical Engineering, School of Engineering, University of Galway, Galway, Ireland
- Anatomy and Regenerative Medicine Institute (REMEDI), School of Medicine, University of Galway, Galway, Ireland
- CÚRAM, Centre for Research in Medical Devices, University of Galway, Galway, Ireland
| | - Rachel Beatty
- Anatomy and Regenerative Medicine Institute (REMEDI), School of Medicine, University of Galway, Galway, Ireland
- SFI Centre for Advanced Materials and BioEngineering Research Centre (AMBER), Trinity College Dublin, Dublin, Ireland
| | - Eimear Wallace
- Anatomy and Regenerative Medicine Institute (REMEDI), School of Medicine, University of Galway, Galway, Ireland
| | - Joanne O'Dwyer
- Anatomy and Regenerative Medicine Institute (REMEDI), School of Medicine, University of Galway, Galway, Ireland
| | - William Ronan
- Biomedical Engineering, School of Engineering, University of Galway, Galway, Ireland
- Biomechanics Research Centre (BMEC), Biomedical Engineering, School of Engineering, University of Galway, Galway, Ireland
| | - Garry P Duffy
- Anatomy and Regenerative Medicine Institute (REMEDI), School of Medicine, University of Galway, Galway, Ireland
- SFI Centre for Advanced Materials and BioEngineering Research Centre (AMBER), Trinity College Dublin, Dublin, Ireland
- CÚRAM, Centre for Research in Medical Devices, University of Galway, Galway, Ireland
| | - Eimear B Dolan
- Biomedical Engineering, School of Engineering, University of Galway, Galway, Ireland
- Biomechanics Research Centre (BMEC), Biomedical Engineering, School of Engineering, University of Galway, Galway, Ireland
- CÚRAM, Centre for Research in Medical Devices, University of Galway, Galway, Ireland
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Beatty R, Mendez KL, Schreiber LHJ, Tarpey R, Whyte W, Fan Y, Robinson ST, O'Dwyer J, Simpkin AJ, Tannian J, Dockery P, Dolan EB, Roche ET, Duffy GP. Soft robot-mediated autonomous adaptation to fibrotic capsule formation for improved drug delivery. Sci Robot 2023; 8:eabq4821. [PMID: 37647382 DOI: 10.1126/scirobotics.abq4821] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 08/02/2023] [Indexed: 09/01/2023]
Abstract
The foreign body response impedes the function and longevity of implantable drug delivery devices. As a dense fibrotic capsule forms, integration of the device with the host tissue becomes compromised, ultimately resulting in device seclusion and treatment failure. We present FibroSensing Dynamic Soft Reservoir (FSDSR), an implantable drug delivery device capable of monitoring fibrotic capsule formation and overcoming its effects via soft robotic actuations. Occlusion of the FSDSR porous membrane was monitored over 7 days in a rodent model using electrochemical impedance spectroscopy. The electrical resistance of the fibrotic capsule correlated to its increase in thickness and volume. Our FibroSensing membrane showed great sensitivity in detecting changes at the abiotic/biotic interface, such as collagen deposition and myofibroblast proliferation. The potential of the FSDSR to overcome fibrotic capsule formation and maintain constant drug dosing over time was demonstrated in silico and in vitro. Controlled closed loop release of methylene blue into agarose gels (with a comparable fold change in permeability relating to 7 and 28 days in vivo) was achieved by adjusting the magnitude and frequency of pneumatic actuations after impedance measurements by the FibroSensing membrane. By sensing fibrotic capsule formation in vivo, the FSDSR will be capable of probing and adapting to the foreign body response through dynamic actuation changes. Informed by real-time sensor signals, this device offers the potential for long-term efficacy and sustained drug dosing, even in the setting of fibrotic capsule formation.
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Affiliation(s)
- Rachel Beatty
- Anatomy and Regenerative Medicine Institute (REMEDI), School of Medicine, University of Galway, Galway, Ireland
- SFI Centre for Advanced Materials and BioEngineering Research (AMBER), Trinity College Dublin, Dublin, Ireland
| | - Keegan L Mendez
- Harvard-MIT Program in Health Sciences and Technology, Cambridge, MA, USA
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Lucien H J Schreiber
- Anatomy and Regenerative Medicine Institute (REMEDI), School of Medicine, University of Galway, Galway, Ireland
| | - Ruth Tarpey
- Anatomy and Regenerative Medicine Institute (REMEDI), School of Medicine, University of Galway, Galway, Ireland
- CÚRAM, Centre for Research in Medical Devices, University of Galway, Galway, Ireland
- Biomedical Engineering, School of Engineering, University of Galway, Galway, Ireland
| | - William Whyte
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Yiling Fan
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Scott T Robinson
- Anatomy and Regenerative Medicine Institute (REMEDI), School of Medicine, University of Galway, Galway, Ireland
- SFI Centre for Advanced Materials and BioEngineering Research (AMBER), Trinity College Dublin, Dublin, Ireland
| | - Joanne O'Dwyer
- Anatomy and Regenerative Medicine Institute (REMEDI), School of Medicine, University of Galway, Galway, Ireland
| | - Andrew J Simpkin
- School of Mathematical and Statistical Sciences, University of Galway, Galway, Ireland
| | - Joseph Tannian
- Anatomy and Regenerative Medicine Institute (REMEDI), School of Medicine, University of Galway, Galway, Ireland
| | - Peter Dockery
- Anatomy and Regenerative Medicine Institute (REMEDI), School of Medicine, University of Galway, Galway, Ireland
| | - Eimear B Dolan
- Anatomy and Regenerative Medicine Institute (REMEDI), School of Medicine, University of Galway, Galway, Ireland
- CÚRAM, Centre for Research in Medical Devices, University of Galway, Galway, Ireland
- Biomedical Engineering, School of Engineering, University of Galway, Galway, Ireland
| | - Ellen T Roche
- Harvard-MIT Program in Health Sciences and Technology, Cambridge, MA, USA
- Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Garry P Duffy
- Anatomy and Regenerative Medicine Institute (REMEDI), School of Medicine, University of Galway, Galway, Ireland
- SFI Centre for Advanced Materials and BioEngineering Research (AMBER), Trinity College Dublin, Dublin, Ireland
- CÚRAM, Centre for Research in Medical Devices, University of Galway, Galway, Ireland
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4
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Ibarz Barberá M, Hernández-Verdejo JL, Bragard J, Morales-Fernández L, Rodríguez-Carrillo L, Martínez Galdón F, Tañá P, Teus MA. Bleb geometry and morphology after Preserflo Microshunt surgery: Risk factors for surgical failure. PLoS One 2023; 18:e0286884. [PMID: 37289791 PMCID: PMC10249890 DOI: 10.1371/journal.pone.0286884] [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: 01/09/2023] [Accepted: 05/25/2023] [Indexed: 06/10/2023] Open
Abstract
PURPOSE To investigate the possible risk factors for treatment failure in patients who had undergone Preserflo Microshunt (PMS) implantation, using anterior-segment optical coherence tomography (AS-OCT) to analyze the internal structures of the bleb. METHODS The PMS blebs of 54 patients were evaluated with AS-OCT. A mathematical model was used to calculate the total filtering surface of the episcleral fluid cavity (EFC) and the hydraulic conductivity (HC) of the bleb wall. Complete and qualified success were defined as IOP between 6 and 17 mmHg with or without glaucoma medication. The relation between baseline characteristics and probability of bleb success was analyzed by bivariate and multivariate logistic regression. The main outcome measures were mean bleb wall thickness (BWT), reflectivity (BWR), HC, mean horizontal and vertical diameter and total filtering surface (TFS) of the EFC. RESULTS Blebs from 74% patients were considered as complete success and 26% as failure. BWR and BWT increased linearly up to the first year in both groups. BWR was higher in the group failure (p = 0.02) and BWT in the group success (p<0.001). EFC was wider and shorter in the success group (p = 0.009, p = 0.03). Higher TFS showed a negative correlation with IOP (r = -0.4, p = 0.002). Higher baseline IOP was associated with success of PMS by multivariate analysis (p = 0.01). Mean HC, 0.034 ± 0.008 (μL/min)/mm2/mmHg, was negatively correlated with bleb surface (r = -0.5, p<0.0001) and wall´s thickness (r = -0.3, p = 0.01). CONCLUSIONS AS-OCT revealed that successful PMS blebs could show either thick hyporreflective walls or wide filtering surfaces with thin capsules. A higher baseline IOP increased the probability of surgical success.
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Affiliation(s)
| | | | | | | | | | | | - Pedro Tañá
- Oftalvist Group, Vistahermosa Hospital, Alicante, Spain
| | - Miguel A. Teus
- Príncipe de Asturias University Hospital, University of Alcalá, Alcalá de Henares, Madrid, Spain
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5
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Young AK, Vanderveen DK. Controversies in Pediatric Angle Surgery and Secondary Surgical Treatment. Semin Ophthalmol 2023; 38:248-254. [PMID: 36472368 DOI: 10.1080/08820538.2022.2152711] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Pediatric glaucoma is a constellation of challenging ophthalmic conditions that, left untreated, can result in irreversible vision loss. The mainstay of treatment for primary congenital glaucoma and select secondary glaucoma subtypes is angle surgery, either trabeculotomy or goniotomy. More recently, MIGS devices have been utilized to enhance the efficacy of these procedures. Despite the high success rates of these primary surgical options, refractory cases are challenging to manage. There is no consensus on the next step of treatment following primary angle surgery. Glaucoma drainage devices and trabeculectomies have been the traditional options, with laser treatment reserved for more severe cases. The benefits and disadvantages of each of these options are discussed.
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Affiliation(s)
- Alexander K Young
- Department of Ophthalmology, Boston Children's Hospital, Boston, MA, USA
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Pereira ICF, Wyss HM, Pinchuk L, Beckers HJM, den Toonder JMJ. A model for designing intraocular pressure-regulating glaucoma implants. PLoS One 2022; 17:e0273672. [PMID: 36054120 PMCID: PMC9439203 DOI: 10.1371/journal.pone.0273672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 08/11/2022] [Indexed: 12/02/2022] Open
Abstract
Glaucoma is a group of eye conditions that damage the optic nerve, the health of which is vital for vision. The key risk factor for the development and progression of this disease is increased intraocular pressure (IOP). Implantable glaucoma drainage devices have been developed to divert aqueous humor from the glaucomatous eye as a means of reducing IOP. The artificial drainage pathway created by these devices drives the fluid into a filtering bleb. The long-term success of filtration surgery is dictated by the proper functioning of the bleb and overlying Tenon’s and conjunctival tissue. To better understand the influence of the health condition of these tissues on IOP, we have developed a mathematical model of fluid production in the eye, its removal from the anterior chamber by a particular glaucoma implant–the PRESERFLO® MicroShunt–, drainage into the bleb and absorption by the subconjunctival vasculature. The mathematical model was numerically solved by commercial FEM package COMSOL. Our numerical results of IOP for different postoperative conditions are consistent with the available evidence on IOP outcomes after the implantation of this device. To obtain insight into the adjustments in the implant’s hydrodynamic resistance that are required for IOP control when hypotony or bleb scarring due to tissue fibrosis take place, we have simulated the flow through a microshunt with an adjustable lumen diameter. Our findings show that increasing the hydrodynamic resistance of the microshunt by reducing the lumen diameter, can effectively help to prevent hypotony. However, decreasing the hydrodynamic resistance of the implant will not sufficiently decrease the IOP to acceptable levels when the bleb is encapsulated due to tissue fibrosis. Therefore, to effectively reduce IOP, the adjustable glaucoma implant should be combined with a means of reducing fibrosis. The results reported herein may provide guidelines to support the design of future glaucoma implants with adjustable hydrodynamic resistances.
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Affiliation(s)
- Inês C. F. Pereira
- Microsystems, Department of Mechanical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
- Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Hans M. Wyss
- Microsystems, Department of Mechanical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
- Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Leonard Pinchuk
- InnFocus, Inc., a Santen Company, Miami, Florida, United States of America
- Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida, United States of America
| | - Henny J. M. Beckers
- University Eye Clinic Maastricht, Maastricht University Medical Centre+ (MUMC+), Maastricht, The Netherlands
| | - Jaap M. J. den Toonder
- Microsystems, Department of Mechanical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
- Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, Eindhoven, The Netherlands
- * E-mail:
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Graf T, Kancerevycius G, Jonušauskas L, Eberle P. Rational Design of Microfluidic Glaucoma Stent. MICROMACHINES 2022; 13:mi13060978. [PMID: 35744591 PMCID: PMC9229318 DOI: 10.3390/mi13060978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 06/17/2022] [Accepted: 06/17/2022] [Indexed: 02/01/2023]
Abstract
Glaucoma is a common, irreparable eye disease associated with high intraocular pressure. One treatment option is implantation of a stent to lower the intraocular pressure. A systematic approach to develop a microchannel stent meshwork that drains aqueous humor from the anterior chamber of the eye into the subconjunctival space is presented. The stent has a large number of outlets within its mesh structure that open into the subconjunctiva. The development approach includes a flow resistance model of the stent. Local adaption of the stent’s tubular dimensions allows for adjustment of the flow resistance. In this way, an evenly distributed outflow into the subconjunctiva is achieved. We anticipate that microblebs will form at the stent outlets. Their size is crucial for drainage and control of intraocular pressure. An analytical model for bleb drainage is developed based on the porous properties of the subconjunctival tissue. Both models—the stent flow resistance model and the bleb drainage model—are verified by numerical simulation. The models and numerical simulation are used to predict intraocular pressure after surgery. They allow for a systematic and personalized design of microchannel stents. Stents designed in this way can stabilize the intraocular pressure between an upper and lower limit.
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Affiliation(s)
- Thomas Graf
- Institute of Electrical Engineering, Lucerne University of Applied Sciences, CH-6048 Horw, Switzerland;
| | - Gitanas Kancerevycius
- Valsigna GmbH, Via Luganetto 4, CH-6962 Lugano-Viganello, Switzerland; (G.K.); (L.J.)
| | - Linas Jonušauskas
- Valsigna GmbH, Via Luganetto 4, CH-6962 Lugano-Viganello, Switzerland; (G.K.); (L.J.)
| | - Patric Eberle
- Institute of Electrical Engineering, Lucerne University of Applied Sciences, CH-6048 Horw, Switzerland;
- Correspondence: ; Tel.: +41-41-349-35-04
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Anterior Segment-Optical Coherence Tomography Bleb Morphology Comparison in Minimally Invasive Glaucoma Surgery: XEN Gel Stent vs. PreserFlo MicroShunt. Diagnostics (Basel) 2022; 12:diagnostics12051250. [PMID: 35626405 PMCID: PMC9141468 DOI: 10.3390/diagnostics12051250] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 05/16/2022] [Accepted: 05/16/2022] [Indexed: 02/07/2023] Open
Abstract
Background: The purpose of this study is to compare the morphology of six-month follow-up blebs created by a subconjunctival glaucoma surgical device (XEN45) to those created by a PreserFlo MicroShunt with a sub-Tenon insertion, utilizing AS-OCT. Methods: A retrospective study of 29 eyes who underwent XEN45 implantation and 29 eyes who underwent PreserFlo MicroShunt implantation. The patients were analyzed at 24 h, 1 week, 1 month, 3 months and 6 months. At each visit, the maturation and morphological alterations of the blebs were observed, as well as connections with the IOP. Results: In both groups, IOP showed significant reduction at all follow ups (p < 0.0001). In XEN group, the most common bleb morphology in the immediate postoperative was the subconjuntival separation type (42%) followed by the uniform type (34%), with a trend inversion at 6 month follow up (51% of uniform type). On the contrary, the most common morphology after PreserFlo was the multiple internal layer (55%), which showed a tendency to reduce over time and was substituted by the microcystic multiform, whose percentage increased over time (17% at day 1 vs. 44% at month 6). Uniform appearance was associated by the posterior episcleral fluid (PEF) lake presence. Both horizontal and vertical diameters significantly increased over time. Conclusion: XEN and PreserFlo implantation resulted in the production of diffuse blebs with different characteristics, which may influence IOP lowering capacity and bleb revisions necessity over time.
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AlJaloud A, AlHilali S, Edward DP, Ahmad K, Malik R. Preliminary Surgical Outcomes of a Trimmed-Plate Aurolab Aqueous Drainage Implant (AADI) in Eyes at High Risk of Hypotony. Clin Ophthalmol 2022; 16:1487-1496. [PMID: 35592670 PMCID: PMC9113450 DOI: 10.2147/opth.s343378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 03/04/2022] [Indexed: 11/23/2022] Open
Abstract
Purpose We describe the technique of trimming the 350 mm2 AADI glaucoma shunt plate and report preliminary results that test the hypothesis that the IOP-lowering efficacy of the trimmed AADI glaucoma shunt is comparable to the Baerveldt 250 mm2 glaucoma drainage implant with a comparable safety profile to the standard AADI implant. Methods Consecutive patients who had received the modified trimmed-plate AADI, standard AADI and Baerveldt 250 mm2 were included in the study. This included patients with refractory or primary or secondary glaucoma of all ages and eyes with and without previous glaucoma surgery. The decision for trimming the AADI plate was made according to the surgeon’s perceived risk of hypotony. Pre-operative, intraoperative and post-operative data were collected from the hospital electronic medical record system. Surgical success was defined as IOP ≥5 mmHg and ≤21 mmHg on two consecutive visits after 3 months, whilst maintaining at least LP vision and avoiding re-operation for glaucoma. Results The sample consisted of 69 eyes (19 with trimmed-plate AADI implant; 36 eyes with the standard AADI implant and 14 eyes who received a BGI-250). The mean IOP reduction at 1 year was 15 mmHg for the Baerveldt-250, 10 mmHg for the AADI and 13 mmHg for the trimmed-plate AADI. The surgical success rate of the implants over 1 year was 85.7% (95% CI, 53.9–96.2%) for BGI-250, 81.5% (62.6–91.5%) for standard AADI and 78.2% (51.7–91.3%) for the trimmed AADI. Conclusion Trimming the plate of the AADI manually may provide a safe and low-cost method of obtaining a successful surgical outcome in eyes at high risk of hypotony.
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Affiliation(s)
- Ahmad AlJaloud
- Glaucoma Division, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
- King Abdullah bin AbdulAziz University Hospital, Riyadh, Saudi Arabia
| | - Sara AlHilali
- Glaucoma Division, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
| | - Deepak P Edward
- Glaucoma Division, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
- University of Illinois Eye and Ear Infirmary Chicago, Chicago, IL, USA
| | - Khabir Ahmad
- Research Department, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
- Correspondence: Khabir Ahmad, Research Department, King Khaled Eye Specialist Hospital, Al Aruba Branch Road, Riyadh, 12329, Saudi Arabia, Tel +966 11 482 1308, Email
| | - Rizwan Malik
- Glaucoma Division, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
- Department of Ophthalmology and Visual Sciences, University of Alberta, Edmonton, AB, Canada
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10
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Ibarz Barberá M, Morales Fernández L, Tañá Rivero P, Gómez de Liaño R, Teus MA. Anterior-segment optical coherence tomography of filtering blebs in the early postoperative period of ab externo SIBS microshunt implantation with mitomycin C: Morphological analysis and correlation with intraocular pressure reduction. Acta Ophthalmol 2022; 100:e192-e203. [PMID: 33838021 DOI: 10.1111/aos.14863] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 02/27/2021] [Accepted: 03/16/2021] [Indexed: 12/16/2022]
Abstract
PURPOSE To analyse the morphological evolution of filtering blebs with anterior-segment OCT (AS-OCT) and its correlation with intraocular pressure after ab externo SIBS microshunt implantation with mitomycin C (MMC) during a 3-month follow-up period. METHODS Twenty-eight filtering blebs of 28 patients with open-angle glaucoma were measured horizontally and vertically in the sub-Tenon space with AS-OCT after ab externo SIBS microshunt implantation with MMC. The intraocular pressure (IOP) was monitored simultaneously at each visit. Maturation of and morphological changes in the blebs and correlations with the IOP were recorded. RESULTS The average median preoperative IOP of 20.7 (range, 12-30) mmHg decreased to 8.5 (range, 4-17), 8.9 (range, 5-17), 10.4 (range, 8-16) and 10.9 (range, 9-15) mmHg at 24 hr, 1 week, 1 month and 3 months, respectively (p < 0.001). A multiform morphology on AS-OCT prevailed at all time points, with a 3.5% rate of a uniform bleb morphology at the first week. The horizontal and vertical diameters of the blebs increased from baseline to the third month. The horizontal expansion (406 ± 127 μm on day 7, p = 0.04, 712 ± 211 μm on day 30, p = 0.02 and 952 ± 218 μm on day 90, p < 0.001) was greater than the vertical expansion (16 ± 18 μm, p = 0.3 on day 1, 63 ± 27 μm, p = 0.02 on day 30 and 137 ± 34 μm, p < 0.001 on day 90) without correlation with the IOP (r = -0.3, p = 0.2). CONCLUSION Anterior-segment OCT (AS-OCT) of the filtering blebs formed after ab externo SIBS microshunt implantation showed progressive horizontal and vertical expansion of the blebs in the sub-Tenon space, with a significant peak at the first month not significantly correlated with the decrease in the IOP.
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Affiliation(s)
| | | | | | | | - Miguel A. Teus
- Hospital Clínico Madrid Spain
- Clínica Novovisión Madrid Spain
- Hospital Universitario Príncipe de Asturias Alcalá de Henares, Madrid Spain
- Universidad de Alcalá Alcalá de Henares, Madrid Spain
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van Mechelen RJS, Wolters JE, Bertens CJF, Webers CAB, van den Biggelaar FJHM, Gorgels TGMF, Beckers HJM. Animal models and drug candidates for use in glaucoma filtration surgery: A systematic review. Exp Eye Res 2022; 217:108972. [PMID: 35114212 DOI: 10.1016/j.exer.2022.108972] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 01/14/2022] [Accepted: 01/26/2022] [Indexed: 12/17/2022]
Abstract
Glaucoma, a degenerative disease of the optic nerve, is the leading cause of irreversible blindness worldwide. Currently, there is no curative treatment. The only proven treatment is lowering intraocular pressure (IOP), the most important risk factor. Glaucoma filtration surgery (GFS) can effectively lower IOP. However, approximately 10% of all surgeries fail yearly due to excessive wound healing, leading to fibrosis. GFS animal models are commonly used for the development of novel treatment modalities. The aim of the present review was to provide an overview of available animal models and anti-fibrotic drug candidates. MEDLINE and Embase were systematically searched. Manuscripts until September 1st, 2021 were included. Studies that used animal models of GFS were included in this review. Additionally, the snowball method was used to identify other publications which had not been identified through the systematic search. Two hundred articles were included in this manuscript. Small rodents (e.g. mice and rats) are often used to study the fibrotic response after GFS and to test drug candidates. Due to their larger eyes, rabbits are better suited to develop medical devices. Novel drugs aim to inhibit specific pathways, e.g. through the use of modulators, monoclonal antibodies, aqueous suppressants or gene therapy. Although most newly studied drugs offer a higher safety profile compared to antimetabolites, their efficacy is in most cases lower when compared to MMC. Current literature on animal models and potential drug candidates for GFS were summarized in this review. Future research should focus on refining current animal models (for example through the induction of glaucoma prior to undertaking GFS) and standardizing animal research to ensure a higher reproducibility and reliability across different research groups. Lastly, novel therapies need to be further optimized, e.g. by conducting more research on the dosage, administration route, application frequency, the option of creating combination therapies, or the development of drug delivery systems for sustained release of anti-fibrotic medication.
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Affiliation(s)
- Ralph J S van Mechelen
- University Eye Clinic Maastricht, Maastricht University Medical Center+ (MUMC+), 6202 AZ, Maastricht, the Netherlands; School for Mental Health and Neuroscience, Maastricht University, 6229 ER, Maastricht, the Netherlands; Chemelot Institute for Science and Technology (InSciTe), 6229 GS, Maastricht, the Netherlands.
| | - Jarno Ej Wolters
- University Eye Clinic Maastricht, Maastricht University Medical Center+ (MUMC+), 6202 AZ, Maastricht, the Netherlands; School for Mental Health and Neuroscience, Maastricht University, 6229 ER, Maastricht, the Netherlands; Chemelot Institute for Science and Technology (InSciTe), 6229 GS, Maastricht, the Netherlands
| | - Christian J F Bertens
- University Eye Clinic Maastricht, Maastricht University Medical Center+ (MUMC+), 6202 AZ, Maastricht, the Netherlands; School for Mental Health and Neuroscience, Maastricht University, 6229 ER, Maastricht, the Netherlands; Chemelot Institute for Science and Technology (InSciTe), 6229 GS, Maastricht, the Netherlands
| | - Carroll A B Webers
- University Eye Clinic Maastricht, Maastricht University Medical Center+ (MUMC+), 6202 AZ, Maastricht, the Netherlands
| | - Frank J H M van den Biggelaar
- University Eye Clinic Maastricht, Maastricht University Medical Center+ (MUMC+), 6202 AZ, Maastricht, the Netherlands
| | - Theo G M F Gorgels
- University Eye Clinic Maastricht, Maastricht University Medical Center+ (MUMC+), 6202 AZ, Maastricht, the Netherlands
| | - Henny J M Beckers
- University Eye Clinic Maastricht, Maastricht University Medical Center+ (MUMC+), 6202 AZ, Maastricht, the Netherlands
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12
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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.
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13
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Ibarz Barberá M, Hernández-Verdejo JL, Bragard J, Burguete J, Fernández LM, Rivero PT, de Liaño RG, Teus MA. Evaluation of the Ultrastructural and In Vitro Flow Properties of the PRESERFLO MicroShunt. Transl Vis Sci Technol 2021; 10:26. [PMID: 34792556 PMCID: PMC8606849 DOI: 10.1167/tvst.10.13.26] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Purpose To measure the in vitro flow properties of the PRESERFLO implant for comparison with the theoretical resistance to flow. Methods The PRESERFLO was designed to control the flow of aqueous humor according to the Hagen-Poiseuille (HP) equation. Scanning electron microscopy (SEM) was performed to analyze the ultrastructure, and flow measurements were carried out using a gravity-flow setup. Results SEM images of the PRESERFLO showed luminal diameters of 67.73 × 65.95 µm and 63.66 × 70.54 µm. The total diameter was 337.2 µm, and the wall was 154 µm wide. The theoretical calculation of the resistance to flow (R) for an aqueous humor (AH) viscosity of 0.7185 centipoises (cP) was 1.3 mm Hg/(µL/min). Hence, assuming a constant AH flow of 2 µL/min, the pressure differential across the device (ΔP) was estimated to be 2.6 mm Hg. The gravity-flow experiment allowed us to measure the experimental resistance to flow, which was RE = 1.301 mm Hg/(µL/min), in agreement with the theoretical resistance to flow R given by the HP equation. Conclusions The experimental and theoretical flow testing showed that the pressure drop across this device would not be large enough to avoid hypotony unless the resistance to outflow of the sub-Tenon space was sufficient to control the intraocular pressure in the early postoperative period. Translational Relevance The fluid properties of glaucoma subconjunctival drainage devices determine their specific bleb-forming capacity and ability to avoid hypotony and therefore their safety and efficacy profile.
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Affiliation(s)
- Marta Ibarz Barberá
- Grupo Oftalvist, Madrid, Spain.,Hospital Moncloa, HLA Hospitales, Madrid, Spain
| | | | - Jean Bragard
- Universidad de Navarra, Dept. of Physics and Applied Math
| | | | | | | | | | - Miguel A Teus
- Clínica Novovisión, Madrid, Spain.,Hospital universitario "Príncipe de Asturias," Alcalá de Henares, Madrid, Spain.,Universidad de Alcalá, Alcalá de Henares, Madrid, Spain
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14
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Zhu Y, Xu S, Eisenberg RS, Huang H. A tridomain model for potassium clearance in optic nerve of Necturus. Biophys J 2021; 120:3008-3027. [PMID: 34214534 DOI: 10.1016/j.bpj.2021.06.020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 03/28/2021] [Accepted: 06/14/2021] [Indexed: 12/20/2022] Open
Abstract
Complex fluids flow in complex ways in complex structures. Transport of water and various organic and inorganic molecules in the central nervous system are important in a wide range of biological and medical processes. However, the exact driving mechanisms are often not known. In this work, we investigate flows induced by action potentials in an optic nerve as a prototype of the central nervous system. Different from traditional fluid dynamics problems, flows in biological tissues such as the central nervous system are coupled with ion transport. They are driven by osmosis created by concentration gradient of ionic solutions, which in turn influence the transport of ions. Our mathematical model is based on the known structural and biophysical properties of the experimental system used by the Harvard group Orkand et al. Asymptotic analysis and numerical computation show the significant role of water in convective ion transport. The full model (including water) and the electrodiffusion model (excluding water) are compared in detail to reveal an interesting interplay between water and ion transport. In the full model, convection due to water flow dominates inside the glial domain. This water flow in the glia contributes significantly to the spatial buffering of potassium in the extracellular space. Convection in the extracellular domain does not contribute significantly to spatial buffering. Electrodiffusion is the dominant mechanism for flows confined to the extracellular domain.
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Affiliation(s)
- Yi Zhu
- Department of Mathematics and Statistics, York University, Toronto, Ontario, Canada
| | - Shixin Xu
- Zu Chongzhi Center for Mathematics and Computational Sciences, Division of Natural and Applied Sciences, Duke Kunshan University, Kunshan, China.
| | - Robert S Eisenberg
- Department of Applied Mathematics, Illinois Institute of Technology, Chicago, Illinois; Department of Physiology & Biophysics, Rush University, Chicago, Illinois
| | - Huaxiong Huang
- Department of Mathematics and Statistics, York University, Toronto, Ontario, Canada; Research Centre for Mathematics, Advanced Institute of Natural Sciences, Beijing Normal University (Zhuhai), Zhuhai, China; Division of Science and Technology, BNU-HKBU United International College, Zhuhai, China.
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15
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Chong RS, Crowston JG, Wong TT. Experimental models of glaucoma filtration surgery. Acta Ophthalmol 2021; 99:9-15. [PMID: 32715621 DOI: 10.1111/aos.14485] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 05/09/2020] [Indexed: 12/15/2022]
Abstract
Glaucoma filtration surgery plays an important role in achieving intraocular pressure (IOP) reduction in patients who have high IOP despite maximum medical therapy. Preclinical experimental models of glaucoma filtration surgery contribute a great deal to our knowledge of the wound healing processes that predispose to scarring and may lead to poor outcomes. However, this research needs to be interpreted in the light of the specific study design, animal model and methods used. We review the existing literature addressing various models of experimental glaucoma filtration surgery, discuss the considerations in assessing these models and describe future steps in evaluating potential therapeutics and bleb characteristics that could impact translational research in this field.
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Affiliation(s)
- Rachel S Chong
- Singapore National Eye Centre Singapore Singapore
- Singapore Eye Research Institute Singapore Singapore
- Duke‐NUS Medical School Singapore Singapore
- Genome Institute of Singapore Agency for Science Technology and Research Singapore Singapore
| | - Jonathan G Crowston
- Singapore National Eye Centre Singapore Singapore
- Singapore Eye Research Institute Singapore Singapore
- Duke‐NUS Medical School Singapore Singapore
| | - Tina T Wong
- Singapore National Eye Centre Singapore Singapore
- Singapore Eye Research Institute Singapore Singapore
- Duke‐NUS Medical School Singapore Singapore
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16
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Bhandari A, Bansal A, Sinha N. Effect of aging on heat transfer, fluid flow and drug transport in anterior human eye: A computational study. J Control Release 2020; 328:286-303. [PMID: 32861760 DOI: 10.1016/j.jconrel.2020.08.044] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 08/07/2020] [Accepted: 08/22/2020] [Indexed: 12/15/2022]
Abstract
There are a lot of geometrical and morphological changes that happen in the human eye with age. Primary open-angle glaucoma, which is caused by the increase in intraocular pressure inside the anterior chamber of the eye is also associated with the physiological aging of the eye. Therefore, it is crucial to understand the effects of aging on drug delivery in the human eye when applied topically. Consequently, a numerical model of topical drug delivery for an aging human eye has been developed using commercial software COMSOL Multiphysics in the current study. Three different age groups (young, middle and old) have been considered and the changes in geometrical and tissue properties of different domains of the eye with age have been included in the numerical model. The effect of aging on heat transfer, aqueous humor flow, intraocular pressure and drug concentration in different domains and orientations of the eye have been investigated. Additionally, an attempt has been made to predict the best class of anti-glaucomatic treatment in silico that should be preferred to treat primary open-angle glaucoma effectively. Results illustrate that there is a decrease in the average corneal temperature and an increase in the temperature deviation across the cornea with age. Further, there is a decrease in the aqueous humor flow magnitude in the anterior chamber of the eye and an increase in intraocular pressure in the anterior chamber of older age groups, which leads to primary open-angle glaucoma. The reduced aqueous humor flow leads to increased drug concentration in the anterior chamber as well as iris and reduced drug concentration in the trabecular mesh of the older age groups, thereby affecting the treatment efficacy. Additionally, our simulated results demonstrate that anti-glaucomatic treatments should be more focused on treating the trabecular mesh rather than the ciliary body of the eye.
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Affiliation(s)
- Ajay Bhandari
- Department of Mechanical Engineering, Indian Institute of Technology, Kanpur 208016, India; Department of Mechanical Engineering, Indian Institute of Technology (Indian School of Mines), Dhanbad, Jharkhand 826004, India
| | - Ankit Bansal
- Department of Mechanical and Industrial Engineering, Indian Institute of Technology, Roorkee 247677, India
| | - Niraj Sinha
- Department of Mechanical Engineering, Indian Institute of Technology, Kanpur 208016, India.
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17
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Gillmann K, Mansouri K. Minimally Invasive Surgery, Implantable Sensors, and Personalized Therapies. J Ophthalmic Vis Res 2020; 15:531-546. [PMID: 33133445 PMCID: PMC7591837 DOI: 10.18502/jovr.v15i4.7792] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 07/08/2020] [Indexed: 01/02/2023] Open
Abstract
Glaucoma management has changed dramatically over the last decades, through clinical advances and technological revolutions. This review discusses the latest innovations and challenges faced in the field around three major axes: minimally-invasive glaucoma surgery (MIGS), implantable sensors and injectable therapeutics. Indeed, the vast number of recently developed MIGS techniques has not only provided clinicians with a wide range of therapeutic options, but they have also enabled them to adjust their therapies more finely which may have contributed a more patient-centric decision-making process. Yet, despite considerable advances in the field, the wide heterogeneity in clinical trial designs blurs the surgical outcomes, specificities and indications. Thus, more high-quality data are required to make the choice of a specific MIGS procedure more than an educated guess. Beyond the scope of MIGS, the potential of IOP telemetry for self-assessment of IOP-control through implantable sensors is developing into a real option for clinicians and an empowering opportunity for patients. Indeed, providing patients with direct feedback enables them to take control and have a clearer representation of their care, in turn leading to a better control of the disease. However, there are potential issues with self-monitoring of IOP, such as increased anxiety levels induced by measured IOP fluctuations and peaks, leading to patients self-treating during IOP spikes and additional office visits. Furthermore, the advent of implantable therapeutics may soon provide yet another step towards personalized glaucoma treatment, by offering not only an efficient alternative to current treatments, but also a therapeutic option that may better adapt to patients' lifestyle. After several decades of relative stagnation through the last century, glaucoma has now entered what many view as a golden age for the specialty. Like every revolution, this one brings its fair share of uncertainty, clinical questioning and uneasy periods of adaptation to ever-changing expectations. Yet, while it is impossible to guess what the landscape of glaucoma surgery will be like in ten or fifteen years, data suggest a bright outlook both for patients and clinicians.
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Affiliation(s)
- Kevin Gillmann
- Glaucoma Research Center, Montchoisi Clinic, Swiss Visio, Lausanne, Switzerland
| | - Kaweh Mansouri
- Glaucoma Research Center, Montchoisi Clinic, Swiss Visio, Lausanne, Switzerland
- Department of Ophthalmology, University of Colorado School of Medicine, Denver, CO, USA
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18
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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: 10] [Impact Index Per Article: 2.5] [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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19
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Affiliation(s)
- Abdelrahman M. Elhusseiny
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA
| | - Deborah K. VanderVeen
- Department of Ophthalmology, Boston Children’s Hospital, Harvard Medical School, Boston, MA, USA
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA
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20
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Gillmann K, Mansouri K. Minimally Invasive Glaucoma Surgery: Where Is the Evidence? Asia Pac J Ophthalmol (Phila) 2020; 9:203-214. [PMID: 32501895 PMCID: PMC7299223 DOI: 10.1097/apo.0000000000000294] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Accepted: 04/04/2020] [Indexed: 12/12/2022] Open
Abstract
PURPOSE The last decade has witnessed an unprecedented growth in glaucoma treatment options through the introduction of minimally invasive glaucoma surgeries (MIGS). The aim of the present review is to provide an understanding of the currently available MIGS and to examine what data are currently available to guide treatment choice. DESIGN Meta-analysis and systematic review of randomized and non-randomized control trials. METHODS Out of 2567 articles identified, a total of 77 articles were retained for analysis, including 28 comparative studies and 12 randomized control trials. Overall, 7570 eyes were included. When data permitted, the weighted mean difference in intraocular pressure reduction was calculated for comparison purposes. RESULTS Weighted mean intraocular pressure reductions from all analyzed studies were: 15.3% (iStent), 29.1% (iStent inject), 36.2% (ab interno canaloplasty), 34.4% (Hydrus), 36.5% (gonioscopically-assisted transluminal trabeculotomy), 24.0% (trabectome), 25.1% (Kahook dual blade), 30.2% (Cypass), 38.8% (XEN), and 50.0% (Preserflo). CONCLUSIONS One of the advantages of the heterogenous range of available MIGS options is the chance to tailor therapy in an individualized manner. However, high-quality data are required to make this choice more than an educated guess. Overall, this review confirms the efficiency of assessed MIGS compared with standalone phacoemulsification, but it highlights that only few studies compare different MIGS techniques and even fewer assess MIGS against criterion standard treatments. Current evidence, while non-negligible, is mostly limited to heterogenous nonrandomized studies and uncontrolled retrospective comparisons, with few quality randomized control trials. We suggest that future research should be comparative and include relevant comparators, standardized to report key outcome features, long-term to assess sustainability and late complications, and ideally randomized.
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Affiliation(s)
- Kevin Gillmann
- Glaucoma Research Center, Montchoisi Clinic, Swiss Visio, Lausanne, Switzerland
| | - Kaweh Mansouri
- Glaucoma Research Center, Montchoisi Clinic, Swiss Visio, Lausanne, Switzerland
- Department of Ophthalmology, University of Colorado School of Medicine, Denver, CO, USA
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21
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Bouremel Y, Lee RMH, Eames I, Brocchini S, Khaw PT. Novel approaches to model effects of subconjunctival blebs on flow pressure to improve clinical grading systems after glaucoma drainage surgery. PLoS One 2019; 14:e0221715. [PMID: 31647822 PMCID: PMC6812775 DOI: 10.1371/journal.pone.0221715] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 08/13/2019] [Indexed: 12/28/2022] Open
Abstract
Clinical grading systems following glaucoma filtration surgery do not include any effects of the bleb on the intra-ocular pressure and are relatively subjective, therefore carrying the risk of inter and/or intra-observer variability. The main objective of the study is to quantify and model the effect of subconjunctival bleb on flow pressure for assessment of clinical grading following glaucoma surgery. Subconjunctival bleb was created by inserting a tube into ex vivo rabbit eyes via an ab externo approach through the anterior chamber and exiting into the subconjunctival space. Sterile dyed water was injected through the tube into the developing bleb. For the in vitro approach a silicone bleb was created by clamping a circular silicone sheet, injecting dyed water through a fixed resistance outlet tube. Photographic measurements of the bleb height, planform area and pressure were taken as a function of time. Clinical blebs were also collected over a few months. Mathematical algorithm software was used to build the bleb model. Bleb height and volume increase as pressure in the bleb increases. The bleb planform area tended to a constant determined by the section of conjunctiva prior to shunt insertion. These increases were in accordance with the bleb model developed in the Appendix. They show that the pressure in the bleb is related to the resistance of the outflow. The linearity of clinical grading systems is reviewed and a new grading approach is proposed. The pressure in the bleb has a strong dependence on bleb extent, height and a weak dependence on conjunctival thickness. The pressure in a bleb can be estimated from bleb height, radius, and flow rate inlet in agreement with the bleb flow model. These results provide support for an improved bleb categorization system.
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Affiliation(s)
- Yann Bouremel
- National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom
- UCL Department of Mechanical Engineering, London, United Kingdom
- UCL School of Pharmacy, London, United Kingdom
| | - Richard M. H. Lee
- National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom
- Chelsea and Westminster Hospital NHS Foundation Trust, London, United Kingdom
| | - Ian Eames
- National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom
- UCL Department of Mechanical Engineering, London, United Kingdom
| | - Steve Brocchini
- National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom
- UCL School of Pharmacy, London, United Kingdom
| | - Peng Tee Khaw
- National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, United Kingdom
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22
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Westermeyer HD, Salmon B, Baynes R, Yeatts J, Khattab A, Oh A, Mowat F. Safety and efficacy of topically applied 0.5% and 1% pirfenidone in a canine model of subconjunctival fibrosis. Vet Ophthalmol 2019; 22:502-509. [DOI: 10.1111/vop.12619] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 08/27/2018] [Accepted: 09/02/2018] [Indexed: 11/29/2022]
Affiliation(s)
- Hans D. Westermeyer
- Department of Clinical Sciences College of Veterinary Medicine North Carolina State University Raleigh North Carolina
| | - Beth Salmon
- Department of Clinical Sciences College of Veterinary Medicine North Carolina State University Raleigh North Carolina
| | - Ronald Baynes
- Center for Chemical Toxicology Research and Pharmacokinetics Department of Population Health and Pathobiology College of Veterinary Medicine North Carolina State University Raleigh North Carolina
| | - James Yeatts
- Center for Chemical Toxicology Research and Pharmacokinetics Department of Population Health and Pathobiology College of Veterinary Medicine North Carolina State University Raleigh North Carolina
| | - Ahlam Khattab
- Center for Chemical Toxicology Research and Pharmacokinetics Department of Population Health and Pathobiology College of Veterinary Medicine North Carolina State University Raleigh North Carolina
| | - Annie Oh
- Department of Clinical Sciences College of Veterinary Medicine North Carolina State University Raleigh North Carolina
| | - Freya Mowat
- Department of Clinical Sciences College of Veterinary Medicine North Carolina State University Raleigh North Carolina
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23
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Coote M. Blebs, Barriers, and Bagpipes: Why is It so Hard? J Curr Glaucoma Pract 2016; 10:79-84. [PMID: 27857486 PMCID: PMC5104966 DOI: 10.5005/jp-journals-10008-1206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 06/16/2016] [Indexed: 11/23/2022] Open
Abstract
Doug Johnson was a clinician-scientist who made great contributions to the understanding of outflow from the eye. This lecture is in honour of Doug and explores the author's understanding of outflow in the surgical context. HOW TO CITE THIS ARTICLE Coote M. Blebs, Barriers, and Bagpipes: Why is It so Hard? J Curr Glaucoma Pract 2016; 10(3):79-84.
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Affiliation(s)
- Michael Coote
- Associate Professor, Department of Center for Eye Research Australia, The University of Melbourne, Parkville, Victoria, Australia
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24
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Pandav SS, Ross CM, Thattaruthody F, Nada R, Singh N, Gautam N, Beirne S, Wallace GG, Sherwood MB, Crowston JG, Coote M. Porosity of Bleb Capsule declines rapidly with Fluid Challenge. J Curr Glaucoma Pract 2016; 10:91-96. [PMID: 27857488 PMCID: PMC5104968 DOI: 10.5005/jp-journals-10008-1208] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Accepted: 06/16/2016] [Indexed: 12/02/2022] Open
Abstract
Introduction The porosity of the fibrous capsule around a glaucoma drainage device (GDD) may be the most important functional attribute. The factors that determine capsular porosity are not well understood. Failed GDD surgeries are usually associated with thick impervious capsules and components of aqueous have been implicated in this process. Purpose In this study, we interrogated the effect of passage of nonaqueous fluid on capsular porosity in mature (but aqueous naïve) blebs in a previously reported GDD model (the “Center for Eye Research Australia Implant”). Materials and methods The study was performed at two centers using 17 New Zealand White (NZW) rabbits. An experimental GDD was implanted into the subconjunctival space but without connection to the anterior chamber. After 28 days, balanced salt solution (BSS) was passed through the implant for 30 to 40 minutes at 12 mm Hg. Capsular porosity was measured as flow (μL/min) at a constant pressure. Porosity of the capsule was retested at 3 and 6 days. Results There was a marked reduction in capsular porosity within 3 days of exposure to BSS (fluid challenge). Even though the baseline porosity was significantly different in the two groups (3.00 ± 0.5 μL/min and 29.67 ± 12.12 μL/min, p < 0.001), the effect of passage of BSS was similar. Capsular porosity fell by approximately 80% in both groups from baseline after single BSS challenge. Capsular thickness was significantly less in Advanced Eye Center (AEC) rabbits at baseline. There was no change in the capsular thickness before and after single fluid challenge. Conclusion Passage of BSS at physiological pressures for under 40 minutes caused marked reduction in the porosity of the fibrous capsule within 3 days. This was not associated with any significant thickening of the fibrous capsule within this time frame. How to cite this article Pandav SS, Ross CM, Thattaruthody F, Nada R, Singh N, Gautam N, Beirne S, Wallace GG, Sherwood MB, Crowston JG, Coote M. Porosity of Bleb Capsule declines rapidly with Fluid Challenge. J Curr Glaucoma Pract 2016;10(3):91-96.
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Affiliation(s)
- Surinder S Pandav
- Professor, Advanced Eye Center, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Craig M Ross
- Research Fellow, Center for Eye Research Australia, University of Melbourne Melbourne, Victoria, Australia
| | - Faisal Thattaruthody
- Senior Registrar, Advanced Eye Center, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Ritambhra Nada
- Professor, Department of Pathology, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Nirbhai Singh
- Assistant Professor, Advanced Eye Center, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Natasha Gautam
- Senior Registrar, Advanced Eye Center, Postgraduate Institute of Medical Education and Research, Chandigarh, India
| | - Stephen Beirne
- Senior Research Fellow, Intelligent Polymer Research Institute/AIIM Faculty, University of Wollongong, Wollongong, New South Wales, Australia
| | - Gordon G Wallace
- Professor, Intelligent Polymer Research Institute, ARC Centre of Excellence for Electromaterials Science, University of Wollongong Wollongong, New South Wales, Australia
| | - Mark B Sherwood
- Professor, Department of Ophthalmology, University of Florida, Gainesville Florida, United States
| | - Jonathan G Crowston
- Managing Director, Center for Eye Research Australia, University of Melbourne Melbourne, Victoria, Australia
| | - Michael Coote
- Associate Professor, Center for Eye Research Australia, University of Melbourne Melbourne, Victoria, Australia
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Schlunck G, Meyer-ter-Vehn T, Klink T, Grehn F. Conjunctival fibrosis following filtering glaucoma surgery. Exp Eye Res 2016; 142:76-82. [PMID: 26675404 DOI: 10.1016/j.exer.2015.03.021] [Citation(s) in RCA: 108] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 03/09/2015] [Accepted: 03/12/2015] [Indexed: 12/28/2022]
Abstract
Despite advances in surgical technique and postoperative care, fibrosis remains the major impediment to a marked reduction of intraocular pressure without the need of additional medication (complete success) following filtering glaucoma surgery. Several aspects specific to filtering surgery may contribute to enhanced fibrosis. Changes in conjunctival tissue structure and composition due to preceding treatments as well as alterations in interstitial fluid flow and content due to aqueous humor efflux may act as important drivers of fibrosis. In light of these pathophysiological considerations, current and possible future strategies to control fibrosis following filtering glaucoma surgery are discussed.
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Affiliation(s)
- Günther Schlunck
- Eye Center, Freiburg University Medical Center, Freiburg, Germany.
| | | | - Thomas Klink
- Dept. of Ophthalmology, Würzburg University Hospital, Würzburg, Germany
| | - Franz Grehn
- Dept. of Ophthalmology, Würzburg University Hospital, Würzburg, Germany
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26
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Coote M, Crowston J. Revision Trabeculectomy: Pearls and Pitfalls. J Curr Glaucoma Pract 2012; 6:131-8. [PMID: 26997769 PMCID: PMC4741115 DOI: 10.5005/jp-journals-10008-1120] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Accepted: 08/29/2012] [Indexed: 11/23/2022] Open
Abstract
Revision trabeculectomy is used to describe any surgical intervention subsequent to an existing trabeculectomy. Mostly, it is used to describe resurgery for failure of trabeculectomy, as defined by inadequate pressure control. Revision may also be performed for unsafe, uncomfortable or leaking blebs. Mostly bleb failure occurs within the subconjunctival space, although the flap and ostium may be involved or causative. Clear surgical principles, meticulous surgical technique and scrupulous postoperative care are key to successful revision surgery. This review is an attempt to elucidate the technique of bleb revision for bleb failure. How to cite this article: Coote M, Crowston J. Revision Trabeculectomy: Pearls and Pitfalls. J Current Glau Prac 2012;6(3):131-138.
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Affiliation(s)
- Michael Coote
- Glaucoma Facility, Royal Victorian Eye and Ear Hospital and Centre for Eye Research, Melbourne, Australia
| | - Jonathan Crowston
- Professor and Head, Glaucoma Research Unit, Royal Victorian Eye and Ear Hospital and Centre for Eye Research, Melbourne, Australia
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Niederer P, Fankhauser F, Kwasniewska S. [Hydrodynamics of aqueous humor in chronic simple glaucoma : Mechanisms of pressure normalization by an artificial outflow system]. Ophthalmologe 2012; 109:30-6. [PMID: 22274295 DOI: 10.1007/s00347-011-2478-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
To help elucidate the interplay of physical forces, in particular pressure and flow, controlling the distribution and absorption of aqueous humor in subconjunctival tissue, a recently published computational model was considered where the fluid production in the eye, its removal via the trabecular/uveoscleral pathways and a surgical pathway are taken into account. The target quantity is the intraocular pressure. The surgical outflow pathway is linked to a fluid bleb that is positioned below the subconjunctival tissue and is modeled as a porous medium. The computational study was conducted on the basis of the geometry and relevant parameters characterizing fluid production, the surgically formed fluid pathway as well as absorption by the subconjunctival vessels, the hydraulic and geometrical characteristics of the bleb and the outflow facility. Clinical observations can be physically interpreted on the basis of parametric studies.
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Affiliation(s)
- P Niederer
- Institut für Biomedizinische Technik, Universität und ETH Zürich, Gloriastr. 35, 8092, Zürich, Schweiz.
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Yang Y, Di Y, Gui DM, Liu ZL, Liu X, Gao DW. IOP-lowering effects for the application of human umbilical vein in non-penetrating deep sclerostomy in rabbits. Int J Ophthalmol 2011; 4:55-7. [PMID: 22553609 DOI: 10.3980/j.issn.2222-3959.2011.01.12] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2010] [Accepted: 01/05/2011] [Indexed: 11/02/2022] Open
Abstract
AIM To estimate the effects of human umbilical vein (HUV) implanted under the sclera of glaucoma model on intraocular pressure (IOP) lowering and to investigate its related mechanisms METHODS A total of 20 human umbilical veins (HUV) were collected from healthy fetus umbilical core. After the establishment of glaucoma model in rabbits, human freeze-dried umbilical vein was implanted under the sclera during NPDS, while for control group, sclerostomy was performed without implant. The formation of the filtration bleb and IOP were detected every 24 hours before surgery and on day 3, 7, 10 and 14 after surgery. Handheld pen-type Tono-pen II tonometer was used to measure IOP after topical anesthesia treatment. Each measurement has three duplicates. The incision recovery, filtration, conjunctiva congestion and anterior chamber inflammation were observed everyday after surgery. RESULTS IOP was decreased dramatically with less inflammation than traditional sclerostomies with the application of HUV. The significant differences of IOP between the NPDS with and without HUV implant groups were shown up from 10 days after surgery. The average IOP in NPDS without HUV implant was 14.25mmHg, while for NPDS with HUV implant group, it was 12.30mmHg. This structure of filtration bleb, which allowed the aqueous humor to leave the eye, was formed for any type of surgery. However, 1-2 weeks later, filtration bleb was still existed in the group of sclerostomy with HUV implant and more stable than that of the surgery without HUV implant. Histological observations were performed on day 3, 7 and 14 after surgery. For the eyes under sclerostomy with HUV implant, HUV lumina was shown up on 3 days after surgery with few fibroblast cells near the sclera. On 7 days after surgery, HUV lumina was stably maintained but with obvious fibroblast cells and inflammatory cell. On 14 days after surgery, HUV lumina was still clearly observed but with scarring formation, which suggests that the IOP lowering effects might result from an effective drainage structure formation. CONCLUSION HUV might be an alternative material to make the drainage pathway for non-penetrating deep sclerostomy.
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Affiliation(s)
- Yang Yang
- Department of Ophthalmology, Shengjing Hospital, China Medical University, Shenyang 110021, Liaoning Province, China
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