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Güven D, Düzgün E, Kutucu OK, Gül C. Evaluation of the Long-Term Clinical Results of 3 Patients Implanted with the Argus II Retinal Prosthesis. Turk J Ophthalmol 2023; 53:58-66. [PMID: 36847635 PMCID: PMC9973216 DOI: 10.4274/tjo.galenos.2022.53598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/01/2023] Open
Abstract
This study presents the long-term clinical results of Argus II retinal prosthesis implantation in eyes with light perception and projection in 3 patients with end-stage retinitis pigmentosa. No conjunctival erosion, hypotony, or implant displacement was observed during postoperative follow-up. The electrical threshold values were lower in the macular region and higher close to the tack fixation region and peripherally. Optical coherence tomography scans showed fibrosis and retinoschisis formation at the retina-implant interface in two cases. This was attributed to mechanical and electrical effects on the tissue due to the active daily use of the system and the electrodes' proximity to the retina. The patients were able to integrate the system into their daily lives and perform activities that they could not do before. Studies on retinal prostheses for the rehabilitation of hereditary retinal diseases are ongoing, so both social and clinical observations and experiences related to the implant are valuable.
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Affiliation(s)
- Dilek Güven
- Acıbadem Maslak Hospital, Clinic of Ophthalmology, İstanbul, Türkiye
| | - Eyüp Düzgün
- University of Health Sciences Türkiye Sultan 2. Abdulhamid Han Training and Research Hospital, Clinic of Ophthalmology, İstanbul, Türkiye
| | - Oğuz Kaan Kutucu
- University of Health Sciences Türkiye Şişli Hamidiye Etfal Training and Research Hospital, Clinic of Ophthalmology, İstanbul, Türkiye
| | - Cengiz Gül
- University of Health Sciences Türkiye Şişli Hamidiye Etfal Training and Research Hospital, Clinic of Ophthalmology, İstanbul, Türkiye
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2
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Karamali F, Behtaj S, Babaei-Abraki S, Hadady H, Atefi A, Savoj S, Soroushzadeh S, Najafian S, Nasr Esfahani MH, Klassen H. Potential therapeutic strategies for photoreceptor degeneration: the path to restore vision. J Transl Med 2022; 20:572. [PMID: 36476500 PMCID: PMC9727916 DOI: 10.1186/s12967-022-03738-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 10/29/2022] [Indexed: 12/12/2022] Open
Abstract
Photoreceptors (PRs), as the most abundant and light-sensing cells of the neuroretina, are responsible for converting light into electrical signals that can be interpreted by the brain. PR degeneration, including morphological and functional impairment of these cells, causes significant diminution of the retina's ability to detect light, with consequent loss of vision. Recent findings in ocular regenerative medicine have opened promising avenues to apply neuroprotective therapy, gene therapy, cell replacement therapy, and visual prostheses to the challenge of restoring vision. However, successful visual restoration in the clinical setting requires application of these therapeutic approaches at the appropriate stage of the retinal degeneration. In this review, firstly, we discuss the mechanisms of PR degeneration by focusing on the molecular mechanisms underlying cell death. Subsequently, innovations, recent developments, and promising treatments based on the stage of disorder progression are further explored. Then, the challenges to be addressed before implementation of these therapies in clinical practice are considered. Finally, potential solutions to overcome the current limitations of this growing research area are suggested. Overall, the majority of current treatment modalities are still at an early stage of development and require extensive additional studies, both pre-clinical and clinical, before full restoration of visual function in PR degeneration diseases can be realized.
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Affiliation(s)
- Fereshteh Karamali
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Sanaz Behtaj
- grid.1022.10000 0004 0437 5432Clem Jones Centre for Neurobiology and Stem Cell Research, Griffith University, Queensland, Australia ,grid.1022.10000 0004 0437 5432Menzies Health Institute Queensland, Griffith University, Southport, QLD 4222 Australia
| | - Shahnaz Babaei-Abraki
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Hanieh Hadady
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Atefeh Atefi
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Soraya Savoj
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Sareh Soroushzadeh
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Samaneh Najafian
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Mohammad Hossein Nasr Esfahani
- grid.417689.5Department of Animal Biotechnology, Cell Science Research Center, Royan Institute for Biotechnology, ACECR, Isfahan, Iran
| | - Henry Klassen
- grid.266093.80000 0001 0668 7243Gavin Herbert Eye Institute, Irvine, CA USA
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Yücel EI, Sadeghi R, Kartha A, Montezuma SR, Dagnelie G, Rokem A, Boynton GM, Fine I, Beyeler M. Factors affecting two-point discrimination in Argus II patients. Front Neurosci 2022; 16:901337. [PMID: 36090266 PMCID: PMC9448992 DOI: 10.3389/fnins.2022.901337] [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: 03/21/2022] [Accepted: 07/11/2022] [Indexed: 11/13/2022] Open
Abstract
Two of the main obstacles to the development of epiretinal prosthesis technology are electrodes that require current amplitudes above safety limits to reliably elicit percepts, and a failure to consistently elicit pattern vision. Here, we explored the causes of high current amplitude thresholds and poor spatial resolution within the Argus II epiretinal implant. We measured current amplitude thresholds and two-point discrimination (the ability to determine whether one or two electrodes had been stimulated) in 3 blind participants implanted with Argus II devices. Our data and simulations show that axonal stimulation, lift and retinal damage all play a role in reducing performance in the Argus 2, by either limiting sensitivity and/or reducing spatial resolution. Understanding the relative role of these various factors will be critical for developing and surgically implanting devices that can successfully subserve pattern vision.
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Affiliation(s)
- Ezgi I. Yücel
- Department of Psychology, University of Washington, Seattle, WA, United States
| | - Roksana Sadeghi
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Arathy Kartha
- Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Sandra Rocio Montezuma
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN, United States
| | - Gislin Dagnelie
- Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD, United States
| | - Ariel Rokem
- Department of Psychology, University of Washington, Seattle, WA, United States,eScience Institute, University of Washington, Seattle, WA, United States
| | - Geoffrey M. Boynton
- Department of Psychology, University of Washington, Seattle, WA, United States
| | - Ione Fine
- Department of Psychology, University of Washington, Seattle, WA, United States,*Correspondence: Ione Fine,
| | - Michael Beyeler
- Department of Computer Science, University of California, Santa Barbara, Santa Barbara, CA, United States,Department of Psychological and Brain Sciences, University of California, Santa Barbara, Santa Barbara, CA, United States
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Peña JS, Vazquez M. Harnessing the Neuroprotective Behaviors of Müller Glia for Retinal Repair. FRONT BIOSCI-LANDMRK 2022; 27:169. [PMID: 35748245 PMCID: PMC9639582 DOI: 10.31083/j.fbl2706169] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 04/18/2022] [Accepted: 05/05/2022] [Indexed: 11/29/2022]
Abstract
Progressive and irreversible vision loss in mature and aging adults creates a health and economic burden, worldwide. Despite the advancements of many contemporary therapies to restore vision, few approaches have considered the innate benefits of gliosis, the endogenous processes of retinal repair that precede vision loss. Retinal gliosis is fundamentally driven by Müller glia (MG) and is characterized by three primary cellular mechanisms: hypertrophy, proliferation, and migration. In early stages of gliosis, these processes have neuroprotective potential to halt the progression of disease and encourage synaptic activity among neurons. Later stages, however, can lead to glial scarring, which is a hallmark of disease progression and blindness. As a result, the neuroprotective abilities of MG have remained incompletely explored and poorly integrated into current treatment regimens. Bioengineering studies of the intrinsic behaviors of MG hold promise to exploit glial reparative ability, while repressing neuro-disruptive MG responses. In particular, recent in vitro systems have become primary models to analyze individual gliotic processes and provide a stepping stone for in vivo strategies. This review highlights recent studies of MG gliosis seeking to harness MG neuroprotective ability for regeneration using contemporary biotechnologies. We emphasize the importance of studying gliosis as a reparative mechanism, rather than disregarding it as an unfortunate clinical prognosis in diseased retina.
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Affiliation(s)
- Juan S. Peña
- Department of Biomedical Engineering, Rutgers, The State
University of New Jersey, Piscataway (08854), New Jersey, USA
| | - Maribel Vazquez
- Department of Biomedical Engineering, Rutgers, The State
University of New Jersey, Piscataway (08854), New Jersey, USA
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Vėbraitė I, Hanein Y. Soft Devices for High-Resolution Neuro-Stimulation: The Interplay Between Low-Rigidity and Resolution. FRONTIERS IN MEDICAL TECHNOLOGY 2022; 3:675744. [PMID: 35047928 PMCID: PMC8757739 DOI: 10.3389/fmedt.2021.675744] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 05/14/2021] [Indexed: 12/27/2022] Open
Abstract
The field of neurostimulation has evolved over the last few decades from a crude, low-resolution approach to a highly sophisticated methodology entailing the use of state-of-the-art technologies. Neurostimulation has been tested for a growing number of neurological applications, demonstrating great promise and attracting growing attention in both academia and industry. Despite tremendous progress, long-term stability of the implants, their large dimensions, their rigidity and the methods of their introduction and anchoring to sensitive neural tissue remain challenging. The purpose of this review is to provide a concise introduction to the field of high-resolution neurostimulation from a technological perspective and to focus on opportunities stemming from developments in materials sciences and engineering to reduce device rigidity while optimizing electrode small dimensions. We discuss how these factors may contribute to smaller, lighter, softer and higher electrode density devices.
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Affiliation(s)
- Ieva Vėbraitė
- School of Electrical Engineering, Tel Aviv University, Tel Aviv, Israel
| | - Yael Hanein
- School of Electrical Engineering, Tel Aviv University, Tel Aviv, Israel
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Kartha A, Sadeghi R, Barry MP, Bradley C, Gibson P, Caspi A, Roy A, Dagnelie G. Prosthetic Visual Performance Using a Disparity-Based Distance-Filtering System. Transl Vis Sci Technol 2020; 9:27. [PMID: 33244447 PMCID: PMC7683856 DOI: 10.1167/tvst.9.12.27] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 10/06/2020] [Indexed: 01/31/2023] Open
Abstract
PURPOSE At present, Argus II is the only retinal prosthesis approved by the US Food and Drug Administration that induces visual percepts in people who are blind from end-stage outer retinal degenerations such as retinitis pigmentosa. It has been shown to work well in sparse, high-contrast settings, but in daily practice visual performance with the device is likely to be hampered by the cognitive load presented by a cluttered real-world environment. In this study, we investigated the effect of a stereo-disparity-based distance-filtering system on four experienced Argus II users for a range of tasks: object localization, depth discrimination, orientation and size discrimination, and people detection and direction of motion. METHODS Functional vision was assessed in a semicontrolled setup using unfiltered (normal camera) and distance-filtered (stereo camera) imagery. All tasks were forced choice designs and an extension of signal detection theory to latent (unobservable) variables was used to analyze the data, allowing estimation of person ability (person measures) and task difficulty (item measures) on the same axis. RESULTS All subjects performed better with the distance filter compared with the unfiltered image (P < 0.001 on all tasks except localization). CONCLUSIONS Our results show that depth filtering using a disparity-based algorithm has significant benefits for people with Argus II implants. TRANSLATIONAL RELEVANCE The improvement in functional vision with the distance filter found in this study may have an important impact on vision rehabilitation and quality of life for people with visual prostheses and ultra low vision.
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Affiliation(s)
- Arathy Kartha
- Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Roksana Sadeghi
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | | | - Chris Bradley
- Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Paul Gibson
- Advanced Medical Electronics Corporation, Maple Grove, MN, USA
| | - Avi Caspi
- Second Sight Medical Products, Sylmar, California, USA
- Jerusalem College of Technology, Jerusalem, Israel
| | - Arup Roy
- Second Sight Medical Products, Sylmar, California, USA
| | - Gislin Dagnelie
- Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD, USA
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7
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Abstract
PURPOSE OF REVIEW The goal is providing an update to the latest research surrounding optoelectronic devices, highlighting key studies and benefits and limitations of each device. RECENT FINDINGS The Argus II demonstrated long-term safety after five-year follow-up. Due to lack of tack fixation, subretinal implants appear to displace over time. PRIMA's completed primate trial showed initial safety and potential for improved vision, resulting in ongoing clinical trials Bionic Vision Australia developed a new 44-electrode suprachoroidal device currently in a clinical trial. Orion (cortical stimulation) is currently undergoing a clinical trial to demonstrate safety. SUMMARY Devices using external camera for images are unaffected by corneal or lens opacities but disconnect eye movements from image perception, while the opposite is true for implants directly detecting light. Visual acuity provided by devices is more complicated than implant electrode density and new devices aim to target this with innovative approaches.
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Affiliation(s)
- Victor Wang
- University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Ajay E. Kuriyan
- Retina Service, Wills Eye Hospital, Thomas Jefferson University, Philadelphia, PA, USA
- Flaum Eye Institute, University of Rochester Medical Center, Rochester, NY, USA
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Yue L, Wuyyuru V, Gonzalez-Calle A, Dorn JD, Humayun MS. Retina–electrode interface properties and vision restoration by two generations of retinal prostheses in one patient—one in each eye. J Neural Eng 2020; 17:026020. [DOI: 10.1088/1741-2552/ab7c8f] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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García-Ayuso D, Di Pierdomenico J, Vidal-Sanz M, Villegas-Pérez MP. Retinal Ganglion Cell Death as a Late Remodeling Effect of Photoreceptor Degeneration. Int J Mol Sci 2019; 20:ijms20184649. [PMID: 31546829 PMCID: PMC6770703 DOI: 10.3390/ijms20184649] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 09/09/2019] [Accepted: 09/17/2019] [Indexed: 12/16/2022] Open
Abstract
Inherited or acquired photoreceptor degenerations, one of the leading causes of irreversible blindness in the world, are a group of retinal disorders that initially affect rods and cones, situated in the outer retina. For many years it was assumed that these diseases did not spread to the inner retina. However, it is now known that photoreceptor loss leads to an unavoidable chain of events that cause neurovascular changes in the retina including migration of retinal pigment epithelium cells, formation of “subretinal vascular complexes”, vessel displacement, retinal ganglion cell (RGC) axonal strangulation by retinal vessels, axonal transport alteration and, ultimately, RGC death. These events are common to all photoreceptor degenerations regardless of the initial trigger and thus threaten the outcome of photoreceptor substitution as a therapeutic approach, because with a degenerating inner retina, the photoreceptor signal will not reach the brain. In conclusion, therapies should be applied early in the course of photoreceptor degeneration, before the remodeling process reaches the inner retina.
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Affiliation(s)
- Diego García-Ayuso
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Virgen de la Arrixaca), 30120 Murcia, Spain.
| | - Johnny Di Pierdomenico
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Virgen de la Arrixaca), 30120 Murcia, Spain.
| | - Manuel Vidal-Sanz
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Virgen de la Arrixaca), 30120 Murcia, Spain.
| | - María P Villegas-Pérez
- Departamento de Oftalmología, Facultad de Medicina, Universidad de Murcia, and Instituto Murciano de Investigación Biosanitaria Virgen de la Arrixaca (IMIB-Virgen de la Arrixaca), 30120 Murcia, Spain.
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