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Confalonieri F, La Rosa A, Ottonelli G, Barone G, Ferraro V, Di Maria A, Romano M, Randazzo A, Vallejo-Garcia JL, Vinciguerra P, Petrovski G. Retinitis Pigmentosa and Therapeutic Approaches: A Systematic Review. J Clin Med 2024; 13:4680. [PMID: 39200821 PMCID: PMC11355744 DOI: 10.3390/jcm13164680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2024] [Revised: 08/03/2024] [Accepted: 08/08/2024] [Indexed: 09/02/2024] Open
Abstract
Background: Retinitis pigmentosa (RP) is a group of hereditary retinal dystrophies characterized by progressive degeneration of photoreceptor cells, which results in debilitating visual impairment. This systematic review aims to evaluate the efficacy and safety of emerging treatment modalities for RP, including gene therapy, mesenchymal-cell-based approaches, and supplementary interventions. Methods: A comprehensive search of electronic databases was conducted to identify relevant studies published up to February 2024. Studies reporting outcomes of treatment interventions for RP, including randomized controlled trials, non-randomized studies, and case series, were included. Data extraction and synthesis were performed according to predefined criteria, focusing on assessing the quality of evidence and summarizing key findings. Results: The search yielded 13 studies meeting inclusion criteria, encompassing diverse treatment modalities and study designs. Gene therapy emerged as a promising therapeutic approach, with several studies reporting favorable outcomes regarding visual function preservation and disease stabilization. Mesenchymal-cell-based therapies also demonstrated potential benefits, although evidence remains limited and heterogeneous. Supplementary interventions, including nutritional supplements and neuroprotective agents, exhibited variable efficacy, with conflicting findings across studies. Conclusions: Despite the lack of definitive curative treatments, emerging therapeutic modalities promise to slow disease progression and preserve visual function in individuals with RP. However, substantial gaps in evidence and heterogeneity in study methodologies underscore the need for further research to elucidate optimal treatment strategies, refine patient selection criteria, and enhance long-term outcomes. This systematic review provides a comprehensive synthesis of current evidence and highlights directions for future research to advance the care and management of individuals with RP.
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Affiliation(s)
- Filippo Confalonieri
- Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, 20090 Milan, Italy
- Department of Ophthalmology, IRCCS Humanitas Research Hospital, Rozzano, 20089 Milan, Italy
| | - Antonio La Rosa
- Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, 20090 Milan, Italy
| | - Giovanni Ottonelli
- Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, 20090 Milan, Italy
| | - Gianmaria Barone
- Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, 20090 Milan, Italy
| | - Vanessa Ferraro
- Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, 20090 Milan, Italy
| | - Alessandra Di Maria
- Department of Ophthalmology, IRCCS Humanitas Research Hospital, Rozzano, 20089 Milan, Italy
| | - Mary Romano
- Department of Ophthalmology, IRCCS Humanitas Research Hospital, Rozzano, 20089 Milan, Italy
| | - Alessandro Randazzo
- Department of Ophthalmology, IRCCS Humanitas Research Hospital, Rozzano, 20089 Milan, Italy
| | | | - Paolo Vinciguerra
- Department of Biomedical Sciences, Humanitas University, Pieve Emanuele, 20090 Milan, Italy
- Department of Ophthalmology, IRCCS Humanitas Research Hospital, Rozzano, 20089 Milan, Italy
| | - Goran Petrovski
- Center for Eye Research and Innovative Diagnostics, Department of Ophthalmology, Institute for Clinical Medicine, University of Oslo, Kirkeveien 166, 0450 Oslo, Norway
- Department of Ophthalmology, Oslo University Hospital, Kirkeveien 166, 0450 Oslo, Norway
- Department of Ophthalmology, University of Split School of Medicine and University Hospital Centre, 21000 Split, Croatia
- UKLONetwork, University St. Kliment Ohridski-Bitola, 7000 Bitola, North Macedonia
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Weinlander E, Erb B, Thiessen C. An Eye for an Eye?: Problematic Risk-Benefit Trade-Offs in Whole Eye Transplantation. THE AMERICAN JOURNAL OF BIOETHICS : AJOB 2024; 24:75-79. [PMID: 38635428 DOI: 10.1080/15265161.2024.2328285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/20/2024]
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Whalen M, Akula M, McNamee SM, DeAngelis MM, Haider NB. Seeing the Future: A Review of Ocular Therapy. Bioengineering (Basel) 2024; 11:179. [PMID: 38391665 PMCID: PMC10886198 DOI: 10.3390/bioengineering11020179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 02/03/2024] [Accepted: 02/08/2024] [Indexed: 02/24/2024] Open
Abstract
Ocular diseases present a unique challenge and opportunity for therapeutic development. The eye has distinct advantages as a therapy target given its accessibility, compartmentalization, immune privilege, and size. Various methodologies for therapeutic delivery in ocular diseases are under investigation that impact long-term efficacy, toxicity, invasiveness, and delivery range. While gene, cell, and antibody therapy and nanoparticle delivery directly treat regions that have been damaged by disease, they can be limited in the duration of the therapeutic delivery and have a focal effect. In contrast, contact lenses and ocular implants can more effectively achieve sustained and widespread delivery of therapies; however, they can increase dilution of therapeutics, which may result in reduced effectiveness. Current therapies either offer a sustained release or a broad therapeutic effect, and future directions should aim toward achieving both. This review discusses current ocular therapy delivery systems and their applications, mechanisms for delivering therapeutic products to ocular tissues, advantages and challenges associated with each delivery system, current approved therapies, and clinical trials. Future directions for the improvement in existing ocular therapies include combination therapies, such as combined cell and gene therapies, as well as AI-driven devices, such as cortical implants that directly transmit visual information to the cortex.
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Affiliation(s)
- Maiya Whalen
- Department of Biology, Boston College, Chestnut Hill, MA 02467, USA
| | | | | | - Margaret M DeAngelis
- Department of Ophthalmology, Jacobs School of Medicine & Biomedical Sciences, University at Buffalo, Buffalo, NY 14203, USA
| | - Neena B Haider
- Shifa Precision, Boston, MA 02138, USA
- Department of Cell Biology, Harvard Medical School, Boston, MA 02138, USA
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Wu KY, Mina M, Sahyoun JY, Kalevar A, Tran SD. Retinal Prostheses: Engineering and Clinical Perspectives for Vision Restoration. SENSORS (BASEL, SWITZERLAND) 2023; 23:5782. [PMID: 37447632 PMCID: PMC10347280 DOI: 10.3390/s23135782] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 06/04/2023] [Accepted: 06/19/2023] [Indexed: 07/15/2023]
Abstract
A retinal prosthesis, also known as a bionic eye, is a device that can be implanted to partially restore vision in patients with retinal diseases that have resulted in the loss of photoreceptors (e.g., age-related macular degeneration and retinitis pigmentosa). Recently, there have been major breakthroughs in retinal prosthesis technology, with the creation of numerous types of implants, including epiretinal, subretinal, and suprachoroidal sensors. These devices can stimulate the remaining cells in the retina with electric signals to create a visual sensation. A literature review of the pre-clinical and clinical studies published between 2017 and 2023 is conducted. This narrative review delves into the retinal anatomy, physiology, pathology, and principles underlying electronic retinal prostheses. Engineering aspects are explored, including electrode-retina alignment, electrode size and material, charge density, resolution limits, spatial selectivity, and bidirectional closed-loop systems. This article also discusses clinical aspects, focusing on safety, adverse events, visual function, outcomes, and the importance of rehabilitation programs. Moreover, there is ongoing debate over whether implantable retinal devices still offer a promising approach for the treatment of retinal diseases, considering the recent emergence of cell-based and gene-based therapies as well as optogenetics. This review compares retinal prostheses with these alternative therapies, providing a balanced perspective on their advantages and limitations. The recent advancements in retinal prosthesis technology are also outlined, emphasizing progress in engineering and the outlook of retinal prostheses. While acknowledging the challenges and complexities of the technology, this article highlights the significant potential of retinal prostheses for vision restoration in individuals with retinal diseases and calls for continued research and development to refine and enhance their performance, ultimately improving patient outcomes and quality of life.
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Affiliation(s)
- Kevin Y. Wu
- Department of Surgery, Division of Ophthalmology, University of Sherbrooke, Sherbrooke, QC J1G 2E8, Canada; (K.Y.W.)
| | - Mina Mina
- Department of Mechanical and Manufacturing Engineering, University of Calgary, Calgary, AB T2N 1N4, Canada
| | - Jean-Yves Sahyoun
- Faculty of Medicine, University of Montreal, Montreal, QC H3T 1J4, Canada
| | - Ananda Kalevar
- Department of Surgery, Division of Ophthalmology, University of Sherbrooke, Sherbrooke, QC J1G 2E8, Canada; (K.Y.W.)
| | - Simon D. Tran
- Faculty of Dental Medicine and Oral Health Sciences, McGill University, Montreal, QC H3A 1G1, Canada
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Stieglitz T, Gueli C, Martens J, Floto N, Eickenscheidt M, Sporer M, Ortmanns M. Highly conformable chip-in-foil implants for neural applications. MICROSYSTEMS & NANOENGINEERING 2023; 9:54. [PMID: 37180455 PMCID: PMC10167239 DOI: 10.1038/s41378-023-00527-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 02/26/2023] [Accepted: 03/24/2023] [Indexed: 05/16/2023]
Abstract
Demands for neural interfaces around functionality, high spatial resolution, and longevity have recently increased. These requirements can be met with sophisticated silicon-based integrated circuits. Embedding miniaturized dice in flexible polymer substrates significantly improves their adaptation to the mechanical environment in the body, thus improving the systems' structural biocompatibility and ability to cover larger areas of the brain. This work addresses the main challenges in developing a hybrid chip-in-foil neural implant. Assessments considered (1) the mechanical compliance to the recipient tissue that allows a long-term application and (2) the suitable design that allows the implant's scaling and modular adaptation of chip arrangement. Finite element model studies were performed to identify design rules regarding die geometry, interconnect routing, and positions for contact pads on dice. Providing edge fillets in the die base shape proved an effective measure to improve die-substrate integrity and increase the area available for contact pads. Furthermore, routing of interconnects in the immediate vicinity of die corners should be avoided, as the substrate in these areas is prone to mechanical stress concentration. Contact pads on dice should be placed with a clearance from the die rim to avoid delamination when the implant conforms to a curvilinear body. A microfabrication process was developed to transfer, align, and electrically interconnect multiple dice into conformable polyimide-based substrates. The process enabled arbitrary die shape and size over independent target positions on the conformable substrate based on the die position on the fabrication wafer.
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Affiliation(s)
- Thomas Stieglitz
- Laboratory for Biomedical Microtechnology, Department of Microsystems Engineering - IMTEK, University of Freiburg, D-79110 Freiburg, Germany
- BrainLinks-BrainTools// IMBIT, University of Freiburg, D-79110 Freiburg, Germany
| | - Calogero Gueli
- Laboratory for Biomedical Microtechnology, Department of Microsystems Engineering - IMTEK, University of Freiburg, D-79110 Freiburg, Germany
| | - Julien Martens
- Laboratory for Biomedical Microtechnology, Department of Microsystems Engineering - IMTEK, University of Freiburg, D-79110 Freiburg, Germany
- BrainLinks-BrainTools// IMBIT, University of Freiburg, D-79110 Freiburg, Germany
| | - Niklas Floto
- Laboratory for Biomedical Microtechnology, Department of Microsystems Engineering - IMTEK, University of Freiburg, D-79110 Freiburg, Germany
- BrainLinks-BrainTools// IMBIT, University of Freiburg, D-79110 Freiburg, Germany
| | - Max Eickenscheidt
- Laboratory for Biomedical Microtechnology, Department of Microsystems Engineering - IMTEK, University of Freiburg, D-79110 Freiburg, Germany
| | - Markus Sporer
- Institute of Microelectronics, University of Ulm, D-89081 Ulm, Germany
| | - Maurits Ortmanns
- Institute of Microelectronics, University of Ulm, D-89081 Ulm, Germany
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Ghani N, Bansal J, Naidu A, Chaudhary KM. Long term positional stability of the Argus II retinal prosthesis epiretinal implant. BMC Ophthalmol 2023; 23:70. [PMID: 36797684 PMCID: PMC9933348 DOI: 10.1186/s12886-022-02736-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Accepted: 12/13/2022] [Indexed: 02/18/2023] Open
Abstract
BACKGROUND The Argus II Retinal Prosthesis System (Second Sight Medical Products, Sylmar, California) is an epiretinal prosthesis that serves to provide useful vision to people who are affected by retinal degenerative diseases such as retinitis pigmentosa (RP). The purpose of this study was to analyze postoperative movement of the electrode array. METHODS Five patients diagnosed with profound retinal dystrophy who have undergone implantation of retinal prosthesis at Stony Brook University Hospital. Fundoscopy was performed at postoperative month 1 (M1), month 3 (M3), month 6 (M6), month 12 (M12), and month 24 (M24) visits. Fundoscopy was extracted and analyzed via NIH ImageJ. Data analysis was completed using IBM SPSS. Various lengths and angles were measured each postoperative month using ImageJ. RESULTS There was no significant change in distance between the optic disc and the surgical handle (length AB) over the two-year span (F = 0.196, p = 0.705). There was a significant change in distance of length AB over time between patients between M3 and M6 (p = 0.025). A repeated measures ANOVA revealed that there was statistically significant change of the optic disc-tack-surgical handle angle (𝛾) (M1 to M24) (F = 3.527, p = 0.030). There was no significant change in angle 𝜟 (the angle to the horizontal of the image), angle 𝜶 (tack-optic disc-surgical handle), and angle 𝜷 (optic-disc-surgical handle-tack). CONCLUSION Our results demonstrate that there may be postoperative movement of the retinal prosthesis over time, as a statistically significant downward rotation is reported over the 2 years span. It is important, moving forward, to further study this movement and to take into consideration such movement when designing retinal implants. It is important to note that this study is limited by the small sample size, and therefore, the conclusions drawn are limited.
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Affiliation(s)
- Nimra Ghani
- Department of Ophthalmology, Stony Brook University Hospital, Stony Brook, NY, 11790, USA.
| | - Jahnvi Bansal
- grid.412695.d0000 0004 0437 5731Department of Ophthalmology, Stony Brook University Hospital, Stony Brook, NY 11790 USA
| | - Abhishek Naidu
- grid.412695.d0000 0004 0437 5731Department of Ophthalmology, Stony Brook University Hospital, Stony Brook, NY 11790 USA
| | - Khurram M. Chaudhary
- grid.412695.d0000 0004 0437 5731Department of Ophthalmology, Stony Brook University Hospital, Stony Brook, NY 11790 USA
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Chang AY. Challenges of Treatment Methodologies and the Future of Gene Therapy and Stem Cell Therapy to Treat Retinitis Pigmentosa. Methods Mol Biol 2022; 2560:363-374. [PMID: 36481911 DOI: 10.1007/978-1-0716-2651-1_33] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Retinitis pigmentosa (RP) is a heterogeneous group of hereditary retinal degenerations for which there is currently no cure. Studies investigating the use of gene therapy, gene editing, and stem cells as potential treatment strategies have shown promising results in animal models and some early clinical trials. Even still, major barriers still exist, including the ability to develop therapies that can target the wide range of mutational etiologies and phenotypic presentations that encompass RP. Additionally, effective screening and early diagnosis are crucial for maximum therapeutic potential, especially because many therapeutic agents require a baseline level photoreceptor function.
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Affiliation(s)
- Angela Y Chang
- Edward S. Harkness Eye Institute, Department of Ophthalmology, Columbia University Medical Center, New York, NY, USA.
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Caravaca-Rodriguez D, Gaytan SP, Suaning GJ, Barriga-Rivera A. Implications of Neural Plasticity in Retinal Prosthesis. Invest Ophthalmol Vis Sci 2022; 63:11. [PMID: 36251317 DOI: 10.1167/iovs.63.11.11] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Retinal degenerative diseases such as retinitis pigmentosa cause a progressive loss of photoreceptors that eventually prevents the affected person from perceiving visual sensations. The absence of a visual input produces a neural rewiring cascade that propagates along the visual system. This remodeling occurs first within the retina. Then, subsequent neuroplastic changes take place at higher visual centers in the brain, produced by either the abnormal neural encoding of the visual inputs delivered by the diseased retina or as the result of an adaptation to visual deprivation. While retinal implants can activate the surviving retinal neurons by delivering electric current, the unselective activation patterns of the different neural populations that exist in the retinal layers differ substantially from those in physiologic vision. Therefore, artificially induced neural patterns are being delivered to a brain that has already undergone important neural reconnections. Whether or not the modulation of this neural rewiring can improve the performance for retinal prostheses remains a critical question whose answer may be the enabler of improved functional artificial vision and more personalized neurorehabilitation strategies.
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Affiliation(s)
- Daniel Caravaca-Rodriguez
- Department of Applied Physics III, Technical School of Engineering, Universidad de Sevilla, Sevilla, Spain
| | - Susana P Gaytan
- Department of Physiology, Universidad de Sevilla, Sevilla, Spain
| | - Gregg J Suaning
- School of Biomedical Engineering, University of Sydney, Sydney, Australia
| | - Alejandro Barriga-Rivera
- Department of Applied Physics III, Technical School of Engineering, Universidad de Sevilla, Sevilla, Spain.,School of Biomedical Engineering, University of Sydney, Sydney, Australia
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Elnabawy RH, Abdennadher S, Hellwich O, Eldawlatly S. PVGAN: A generative adversarial network for object simplification in prosthetic vision. J Neural Eng 2022; 19. [PMID: 35981530 DOI: 10.1088/1741-2552/ac8acf] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 08/18/2022] [Indexed: 11/11/2022]
Abstract
OBJECTIVE By means of electrical stimulation of the visual system, visual prostheses provide promising solution for blind patients through partial restoration of their vision. Despite the great success achieved so far in this field, the limited resolution of the perceived vision using these devices hinders the ability of visual prostheses users to correctly recognize viewed objects. Accordingly, we propose a deep learning approach based on Generative Adversarial Networks (GANs), termed PVGAN, to enhance object recognition for the implanted patients by representing objects in the field of view based on a corresponding simplified clip art version. APPROACH To assess the performance, an axon map model was used to simulate prosthetic vision in experiments involving normally-sighted participants. In these experiments, four types of image representation were examined. The first and second types comprised presenting phosphene simulation of real images containing the actual high-resolution object, and presenting phosphene simulation of the real image followed by the clip art image, respectively. The other two types were utilized to evaluate the performance in the case of electrode dropout, where the third type comprised presenting phosphene simulation of only clip art images without electrode dropout, while the fourth type involved clip art images with electrode dropout. MAIN RESULTS The performance was measured through three evaluation metrics which are the accuracy of the participants in recognizing the objects, the time taken by the participants to correctly recognize the object, and the confidence level of the participants in the recognition process. Results demonstrate that representing the objects using clip art images generated by the PVGAN model results in a significant enhancement in the speed and confidence of the subjects in recognizing the objects. SIGNIFICANCE These results demonstrate the utility of using GANs in enhancing the quality of images perceived using prosthetic vision.
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Affiliation(s)
- Reham H Elnabawy
- Digital Media Engineering and Technology, German University in Cairo, German University in Cairo Campus, 5th Settlement, New Cairo, Cairo, Egypt, Cairo, 11835, EGYPT
| | - Slim Abdennadher
- Computer Science and Engineering, German University in Cairo, German University in Cairo Campus, 5th Settlement, New Cairo, Cairo, Egypt, Cairo, 11835, EGYPT
| | - Olaf Hellwich
- Department of Computer Vision & Remote Sensing, Technische Universität Berlin, MAR 6-5 Marchstr. 23 D-10587 Berlin, Berlin, 10623, GERMANY
| | - Seif Eldawlatly
- Computer and Systems Engineering, Ain Shams University Faculty of Engineering, 1 El-sarayat st, Cairo, 11517, EGYPT
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Maimon A, Yizhar O, Buchs G, Heimler B, Amedi A. A case study in phenomenology of visual experience with retinal prosthesis versus visual-to-auditory sensory substitution. Neuropsychologia 2022; 173:108305. [PMID: 35752268 PMCID: PMC9297294 DOI: 10.1016/j.neuropsychologia.2022.108305] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 04/30/2022] [Accepted: 06/13/2022] [Indexed: 11/26/2022]
Abstract
The phenomenology of the blind has provided an age-old, unparalleled means of exploring the enigmatic link between the brain and mind. This paper delves into the unique phenomenological experience of a man who became blind in adulthood. He subsequently underwent both an Argus II retinal prosthesis implant and training, and extensive training on the EyeMusic visual to auditory sensory substitution device (SSD), thereby becoming the first reported case to date of dual proficiency with both devices. He offers a firsthand account into what he considers the great potential of combining sensory substitution devices with visual prostheses as part of a complete visual restoration protocol. While the Argus II retinal prosthesis alone provided him with immediate visual percepts by way of electrically stimulated phosphenes elicited by the device, the EyeMusic SSD requires extensive training from the onset. Yet following the extensive training program with the EyeMusic sensory substitution device, our subject reports that the sensory substitution device allowed him to experience a richer, more complex perceptual experience, that felt more "second nature" to him, while the Argus II prosthesis (which also requires training) did not allow him to achieve the same levels of automaticity and transparency. Following long-term use of the EyeMusic SSD, our subject reported that visual percepts representing mainly, but not limited to, colors portrayed by the EyeMusic SSD are elicited in association with auditory stimuli, indicating the acquisition of a high level of automaticity. Finally, the case study indicates an additive benefit to the combination of both devices on the user's subjective phenomenological visual experience.
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Affiliation(s)
- Amber Maimon
- The Baruch Ivcher Institute for Brain, Cognition, and Technology, The Baruch Ivcher School of Psychology, Reichman University, Herzliya, Israel; The Ruth & Meir Rosenthal Brain Imaging Center, Reichman University, Herzliya, Israel.
| | - Or Yizhar
- The Baruch Ivcher Institute for Brain, Cognition, and Technology, The Baruch Ivcher School of Psychology, Reichman University, Herzliya, Israel; Department of Cognitive and Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel; Max Planck Institute for Human Development, Research Group Adaptive Memory and Decision Making, Berlin, Germany; Max Planck Institute for Human Development, Max Planck Dahlem Campus of Cognition (MPDCC), Berlin, Germany
| | - Galit Buchs
- The Baruch Ivcher Institute for Brain, Cognition, and Technology, The Baruch Ivcher School of Psychology, Reichman University, Herzliya, Israel; Department of Cognitive and Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Benedetta Heimler
- Center of Advanced Technologies in Rehabilitation (CATR), Sheba Medical Center, Ramat Gan, Israel
| | - Amir Amedi
- The Baruch Ivcher Institute for Brain, Cognition, and Technology, The Baruch Ivcher School of Psychology, Reichman University, Herzliya, Israel; The Ruth & Meir Rosenthal Brain Imaging Center, Reichman University, Herzliya, Israel.
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Lindner M, Gilhooley MJ, Hughes S, Hankins MW. Optogenetics for visual restoration: From proof of principle to translational challenges. Prog Retin Eye Res 2022; 91:101089. [PMID: 35691861 DOI: 10.1016/j.preteyeres.2022.101089] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 05/17/2022] [Accepted: 05/19/2022] [Indexed: 01/04/2023]
Abstract
Degenerative retinal disorders are a diverse family of diseases commonly leading to irreversible photoreceptor death, while leaving the inner retina relatively intact. Over recent years, innovative gene replacement therapies aiming to halt the progression of certain inherited retinal disorders have made their way into clinics. By rendering surviving retinal neurons light sensitive optogenetic gene therapy now offers a feasible treatment option that can restore lost vision, even in late disease stages and widely independent of the underlying cause of degeneration. Since proof-of-concept almost fifteen years ago, this field has rapidly evolved and a detailed first report on a treated patient has recently been published. In this article, we provide a review of optogenetic approaches for vision restoration. We discuss the currently available optogenetic tools and their relative advantages and disadvantages. Possible cellular targets will be discussed and we will address the question how retinal remodelling may affect the choice of the target and to what extent it may limit the outcomes of optogenetic vision restoration. Finally, we will analyse the evidence for and against optogenetic tool mediated toxicity and will discuss the challenges associated with clinical translation of this promising therapeutic concept.
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Affiliation(s)
- Moritz Lindner
- The Nuffield Laboratory of Ophthalmology, Jules Thorn SCNi, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, OX1 3QU, United Kingdom; Institute of Physiology and Pathophysiology, Department of Neurophysiology, Philipps University, 35037, Marburg, Germany
| | - Michael J Gilhooley
- The Nuffield Laboratory of Ophthalmology, Jules Thorn SCNi, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, OX1 3QU, United Kingdom; The Institute of Ophthalmology, University College London, EC1V 9EL, United Kingdom; Moorfields Eye Hospital, London, EC1V 2PD, United Kingdom
| | - Steven Hughes
- The Nuffield Laboratory of Ophthalmology, Jules Thorn SCNi, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, OX1 3QU, United Kingdom
| | - Mark W Hankins
- The Nuffield Laboratory of Ophthalmology, Jules Thorn SCNi, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, OX1 3QU, United Kingdom.
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Cai CX, Vajzovic L. INTRAOPERATIVE OPTICAL COHERENCE TOMOGRAPHY AND ENDOSCOPY-GUIDED EXPLANTATION OF ARGUS II DEVICE. Retin Cases Brief Rep 2022; 16:393-396. [PMID: 32195885 PMCID: PMC7494642 DOI: 10.1097/icb.0000000000000994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To describe a surgical approach using intraoperative optical coherence tomography and endoscopy for successful Argus II retinal prosthesis system removal. METHODS Retrospective review of a patient undergoing Argus II explantation 8 months after initial implantation. RESULTS Successful explantation of the Argus II device was performed in this patient. CONCLUSION Explantation of the Argus II device can be a difficult surgery, and intraoperative optical coherence tomography and endoscopy can be used to help avoid potential complications.
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Affiliation(s)
- Cindy X Cai
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina
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Carignan M, Courchesne M, Cantin S, Moore V, Poncet F. Visual Rehabilitation After Retinal Prosthesis Implantation: An 18-month Case Report, From Candidate Selection to Follow-Up. JOURNAL OF VISUAL IMPAIRMENT & BLINDNESS 2022. [DOI: 10.1177/0145482x221092020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Introduction: Various retinal implants are being developed and appear to be a promising option for improving the visual capacities of individuals with retinal dystrophy. A multidisciplinary approach to both assessment of a candidate’s factors and rehabilitation could contribute to improved activity and participation. The purpose of this study was (i) to document the approach taken by a multidisciplinary team in the candidate selection process and in training in the use of the Argus II retinal prosthesis system (RPS), and (ii) to examine the effects of the RPS on sensory and mental functions and on activity and participation. Methods: An A1-B1-A2-B2 experimental case report was used, with repeated measures pre- and post-rehabilitation program design. The A phases represent the periods with the system off, whereas the B phases represent the periods with the system on. A 65-year-old man with retinitis pigmentosa and total blindness was followed by a multidisciplinary team for over 18 months. After receiving the retinal implant, he benefited from a 10-week rehabilitation program (twice per week; B1 phase). Results: Globally, the RPS improved vision in the B phases when the system was on and visual acuity was stable at 2.3 logMAR (functional blindness). The participant’s mental and neuromusculoskeletal function scores were generally stable throughout the data collection periods. Lower performance on some measures at the end of phase B2 coincided with a negative mood. Discussion: Use of the RPS improved activity, but this did not transfer into greater participation in the living environment. Despite efforts made by the rehabilitation team to manage the user’s expectations concerning the RPS, the interventions reactivated his grieving over his vision loss. Implications for Practitioners: New technologies can make users dream of unrealistic possibilities, and managing their expectations requires problem solving supported by a multidisciplinary team.
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Affiliation(s)
- Mathieu Carignan
- Institut Nazareth et Louis Braille du CISSS de la Montérégie-Centre, Longueuil, QC, Canada
- Centre de recherche interdisciplinaire en réadaptation du Montréal métropolitain (CRIR), Montréal, QC, Canada
| | - Marie Courchesne
- Institut Nazareth et Louis Braille du CISSS de la Montérégie-Centre, Longueuil, QC, Canada
- Centre de recherche interdisciplinaire en réadaptation du Montréal métropolitain (CRIR), Montréal, QC, Canada
| | - Sylvie Cantin
- Institut Nazareth et Louis Braille du CISSS de la Montérégie-Centre, Longueuil, QC, Canada
- Centre de recherche interdisciplinaire en réadaptation du Montréal métropolitain (CRIR), Montréal, QC, Canada
| | - Vincent Moore
- Institut Nazareth et Louis Braille du CISSS de la Montérégie-Centre, Longueuil, QC, Canada
- Centre de recherche interdisciplinaire en réadaptation du Montréal métropolitain (CRIR), Montréal, QC, Canada
| | - Frédérique Poncet
- Institut Nazareth et Louis Braille du CISSS de la Montérégie-Centre, Longueuil, QC, Canada
- Centre de recherche interdisciplinaire en réadaptation du Montréal métropolitain (CRIR), Montréal, QC, Canada
- Lethbridge-Layton-Mackay Rehabilitation Center, Integrated Health and Social Services University Network for West-Central Montreal, Montreal, QC, Canada
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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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Markan A, Neupane S, Agrawal R, Gupta V. Newer therapeutic agents for retinal diseases. EXPERT REVIEW OF OPHTHALMOLOGY 2022. [DOI: 10.1080/17469899.2022.2030709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Ashish Markan
- Advanced Eye Centre, Department of Ophthalmology, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Swechya Neupane
- Advanced Eye Centre, Department of Ophthalmology, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
| | - Rupesh Agrawal
- Department of Ophthalmology, National Healthcare Group Eye Institute, Tan Tock Sen Hospital, Novena, Singapore
| | - Vishali Gupta
- Advanced Eye Centre, Department of Ophthalmology, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
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Green RA. Possibilities in bioelectronics: Super humans or science fiction? APL Bioeng 2021; 5:040401. [PMID: 34964001 DOI: 10.1063/5.0079530] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 12/08/2021] [Indexed: 12/16/2022] Open
Abstract
Recent years have led to a rapid increase in the development of neurotechnologies for diagnosis, monitoring, and treatment of conditions with neurological targets. The central driving force has been the need for next-generation devices to treat neural injury and disease, where current pharmaceutical or conventional bioelectronics have been unable to impart sufficient therapeutic effects. The advent of new therapies and advanced technologies has resulted in a reemergence of the concept of superhuman performance. This is a hypothetical possibility that is enabled when bionics are used to augment the neural system and has included the notions of improved cognitive ability and enhancement of hearing and seeing beyond the limitations of a healthy human. It is quite conceivable that a bionic eye could be used for night vision; however, the damage to both the neural system and surrounding tissues in placing such a device is only considered acceptable in the case of a patient that can obtain improvement in quality of life. There are also critical limitations that have hindered clinical translation of high-resolution neural interfaces, despite significant advances in biomaterial and bioelectronics technologies, including the advent of biohybrid devices. Surgical damage and foreign body reactions to such devices can be reduced but not eliminated, and these engineering solutions to reduce inflammation present additional challenges to the long-term performance and medical regulation. As a result, while bioelectronics has seen concepts from science fiction realized, there remains a significant gap to their use as enhancements beyond medical therapies.
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Affiliation(s)
- Rylie A Green
- Department of Bioengineering, Imperial College London, London SW7 2AS, United Kingdom
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Yanagihara RT, Yamane ML, Kokame GT. The First Epiretinal Implant for Hereditary Blindness in the Asia-Pacific Region. HAWAI'I JOURNAL OF HEALTH & SOCIAL WELFARE 2021; 80:10-15. [PMID: 34820630 PMCID: PMC8609197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
In February 2013, the Argus® II Retinal Prosthesis System (Second Sight Medical Products, Inc., Sylmar, CA, US) became the first "bionic eye" approved by the FDA to restore useful vision in patients previously blinded by end-stage retinitis pigmentosa, a hereditary, progressive degeneration of the outer retinal photoreceptor cells. The system captures and converts an external optical input into an electrical signal that activates an epiretinal electrode array on the inner surface of the retina. This signal bypasses dysfunctional photoreceptors and directly stimulates the functional inner retina, thus transmitting information to the visual cortex and creating artificial vision. This article describes the first implantation of the Argus II Retinal Prosthesis System in the Asia-Pacific region, which occurred in a deaf and blind 72-year-old Japanese American woman with Usher syndrome. At 57 months after her operation, the patient uses the device daily to perform visual tasks, and the microelectrode array remains in the proper position on the macula. This case demonstrates the long-term safety and efficacy of the Argus II epiretinal implant, which allowed a functionally blind patient to gain meaningful vision.
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Affiliation(s)
- Ryan T. Yanagihara
- University of Hawai‘i John A. Burns School of Medicine, Honolulu, HI (RTY)
- The Retina Center at Pali Momi, Aiea, HI (RTY,MLMY, GTK)
- Retina Consultants of Hawai‘i, Honolulu, HI (RTY, MLMY, GTK)
- Hawai‘i Macula and Retina Institute, Aiea, HI (RTY, MLMY, GTK)
| | - Maya L.M. Yamane
- University of Hawai‘i Internal Medicine Residency Program, Honolulu, HI (MLMY)
- The Retina Center at Pali Momi, Aiea, HI (RTY,MLMY, GTK)
- Retina Consultants of Hawai‘i, Honolulu, HI (RTY, MLMY, GTK)
- Hawai‘i Macula and Retina Institute, Aiea, HI (RTY, MLMY, GTK)
| | - Gregg T. Kokame
- The Retina Center at Pali Momi, Aiea, HI (RTY,MLMY, GTK)
- Retina Consultants of Hawai‘i, Honolulu, HI (RTY, MLMY, GTK)
- Hawai‘i Macula and Retina Institute, Aiea, HI (RTY, MLMY, GTK)
- Division of Ophthalmology, Department of Surgery, University of Hawai‘i School of Medicine, Honolulu, HI (GTK)
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Elnabawy RH, Abdennadher S, Hellwich O, Eldawlatly S. Electrode Dropout Compensation in Visual Prostheses: An Optimal Object Placement Approach. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2021; 2021:6515-6518. [PMID: 34892602 DOI: 10.1109/embc46164.2021.9630991] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Visual prostheses provide promising solution to the blind through partial restoration of their vision via electrical stimulation of the visual system. However, there are some challenges that hinder the ability of subjects implanted with visual prostheses to correctly identify an object. One of these challenges is electrode dropout; the malfunction of some electrodes resulting in consistently dark phosphenes. In this paper, we propose a dropout handling algorithm for better and faster identification of objects. In this algorithm, phosphenes representing the object are translated to another location within the same image that has the minimum number of dropouts. Using simulated prosthetic vision, experiments were conducted to test the efficacy of our proposed algorithm. Electrode dropout rates of 10%, 20% and 30% were examined. Our results demonstrate significant increase in the object recognition accuracy, reduction in the recognition time and increase in the recognition confidence level using the proposed approach compared to presenting the images without dropout handling.Clinical Relevance- These results demonstrate the utility of dropout handling in enhancing the perception of images in prosthetic vision.
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Parameswarappa DC, Das AV, Dave VP, Agarwal K, Natarajan R, Jalali S. Clinical Presentation and Demographic Distribution of Retinitis Pigmentosa in India and Implications for Potential Treatments: Electronic Medical Records Driven Big Data Analytics: Report I. Semin Ophthalmol 2021; 37:284-290. [PMID: 34404308 DOI: 10.1080/08820538.2021.1957126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
AimTo describe the clinical presentation and demographic distribution of retinitis pigmentosa in patients presenting to a multi-tier ophthalmology hospital network in India and implications for potential treatments.DesignCross-sectional hospital-based study.MethodsThis study included 2,541,810 patients presenting between March 2012 and October 2020. Patients with a clinical diagnosis of retinitis pigmentosa in at least one eye were included as cases. The data were collected using an electronic medical record system.ResultsOverall, 15,062 (0.59%) new patients were diagnosed with retinitis pigmentosa and were included for analysis. The median age was 35 (IQR: 21-49) years and adult age (84.56%) presented more often. The most common presenting age group was between 21 and 30 years (20%). Majority of patients were male (61.68%) and had bilateral (96.39%) affliction. There was a family history in a tenth of the patients (10.46%) and a history of consanguinity in a minority (5.53%). The majority of the eyes had mild or no central visual acuity impairment of <20/70 (34.25%) followed by blindness <20/400 to 20/1200 (21.26%). The predominant retinal signs included disc pallor (76.43%), attenuated arterioles (82.61%) and bony spicule pigmentation (90.15%), and almost all had retinal pigmentary changes. A minority of the eyes underwent a surgical procedure (4.96%).ConclusionRetinitis pigmentosa is commonly bilateral and predominantly affects males. Most patients present in the third decade of life with severe visual acuity impairment. More than half of the eyes from our study are potential candidates for newer therapies. These results have implications for upcoming treatment choices and planning.
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Affiliation(s)
- Deepika C Parameswarappa
- Srimati Kanuri Santhamma Center for Vitreo - Retinal Diseases, L V Prasad Eye Institute, Hyderabad, Telangana, India
| | - Anthony Vipin Das
- Department of eyeSmart EMR & AEye, LV Prasad Eye Institute, Hyderabad, India
| | - Vivek Pravin Dave
- Srimati Kanuri Santhamma Center for Vitreo - Retinal Diseases, L V Prasad Eye Institute, Hyderabad, Telangana, India
| | - Komal Agarwal
- Srimati Kanuri Santhamma Center for Vitreo - Retinal Diseases, L V Prasad Eye Institute, Hyderabad, Telangana, India
| | - Ramya Natarajan
- Department of Ophthalmic Biophysics, Kallam Anji Reddy Campus, L V Prasad Eye Institute, Hyderabad, Telangana, India
| | - Subhadra Jalali
- Srimati Kanuri Santhamma Center for Vitreo - Retinal Diseases, L V Prasad Eye Institute, Hyderabad, Telangana, India
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Xie H, Wang Y, Ye Z, Fang S, Xu Z, Wu T, Chan LLH. Monitoring Cortical Response and Electrode-Retina Impedance Under Epiretinal Stimulation in Rats. IEEE Trans Neural Syst Rehabil Eng 2021; 29:1178-1187. [PMID: 34152987 DOI: 10.1109/tnsre.2021.3090904] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Retinal prosthesis can restore partial vision in patients with retinal degenerative diseases such as retinitis pigmentosa and age-related macular degeneration. Epiretinal prosthesis is one of three therapeutic approaches, which received regulatory approval several years ago. The thresholds of an epiretinal stimulation is partly determined by the size of the physical gap between the electrode and the retina after implantation. Precise positioning of epiretinal stimulating electrode array is still a challenging task. In this study, we demonstrate an approach to positioning epiretinal prostheses for an optimal response at the cortical output by monitoring both the impedance at the electrode-retina interface and the evoked-potential at the cortical level. We implanted a single-channel electrode on the epiretinal surface in adult rats, acutely, guided by both the impedance at the electrode-retina interface and by electrically evoked potentials (EEPs) in the visual cortex during retinal stimulation. We observe that impedance monotonously increases with decreasing electrode-retina distance, but that the strongest cortical responses were achieved at intermediate impedance levels. When the electrode penetrates the retina, the impedance keeps increasing. The effect of stimulation on the retina changes from epiretinal paradigm to intra-retinal paradigm and a decrease in cortical activation is observed. It is found that high impedance is not always favorable to elicit best cortical responses. Histopathological results showed that the electrode was placed at the intra-retinal space at high impedance value. These results show that monitoring impedance at the electrode-retina interface is necessary but not sufficient in obtaining strong evoked-potentials at the cortical level. Monitoring the cortical EEPs together with the impedance can improve the safety of implantation as well as efficacy of stimulation in the next generation of retinal implants.
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Chivers M, Li N, Pan F, Wieffer H, Slowik R, Leartsakulpanitch J. The Burden of X-Linked Retinitis Pigmentosa on Patients and Society: A Narrative Literature Review. CLINICOECONOMICS AND OUTCOMES RESEARCH 2021; 13:565-572. [PMID: 34188501 PMCID: PMC8236258 DOI: 10.2147/ceor.s297287] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 06/10/2021] [Indexed: 01/18/2023] Open
Abstract
X-linked retinitis pigmentosa (XLRP) is a severe form of retinitis pigmentosa (RP), a rare, inherited retinal degenerative disorder, that causes blindness. The aim of this literature review was to identify what is currently known about the burden of XLRP. Literature databases were searched for articles describing the clinical, humanistic, or economic burden of XLRP or RP in the US, Japan, France, Germany, Italy, Spain, and the UK, published in English between 2014 and 2019; gray literature and cited references were reviewed. Literature describing XLRP is limited as this is an ultra-rare condition; findings relating to burden of RP have been reported with interpretation of how burden differs for XLRP. In XLRP, night blindness usually presents in the first decade of life, followed by loss of peripheral and then central vision; legal blindness is reported at a median of 45 years in affected males (vs median 70 years for RP). There is limited evidence of humanistic or economic burden specific to XLRP; one study identified greater vision-related activity limitations in patients with XLRP compared with the wider RP population. Qualitative studies describe increased humanistic burden for people living with RP; difficulty undertaking everyday tasks (driving, hobbies, reading), psychosocial burden and barriers to work and career. People described the emotional impact of dealing with progression of RP, ongoing social and physical challenges, and the impact of RP on relationships. The economic burden of RP is associated with lost productivity, greater healthcare costs and increasing requirement for formal and informal care. In summary, XLRP remains an untreatable condition that can impact people from childhood. The humanistic burden of RP has been shown to increase as the disease progresses; hence, in XLRP the earlier onset and earlier progression to blindness during prime working years may mean a comparatively greater lifetime burden of disease.
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Affiliation(s)
| | - Nan Li
- Janssen Global Services,LLC, Raritan, NJ, 08869, USA
| | - Feng Pan
- Janssen Global Services,LLC, Raritan, NJ, 08869, USA
| | | | - Rafal Slowik
- Janssen Global Services,LLC, Raritan, NJ, 08869, USA
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22
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Chenais NAL, Airaghi Leccardi MJI, Ghezzi D. Naturalistic spatiotemporal modulation of epiretinal stimulation increases the response persistence of retinal ganglion cell. J Neural Eng 2021; 18. [DOI: 10.1088/1741-2552/abcd6f] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Accepted: 11/24/2020] [Indexed: 12/24/2022]
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Lai FHP, Wong EWN, Lam WC, Lee TC, Wong SC, Nagiel A, Lam RF. Endoscopic vitreoretinal surgery: Review of current applications and future trends. Surv Ophthalmol 2020; 66:198-212. [PMID: 33278403 DOI: 10.1016/j.survophthal.2020.11.004] [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: 07/07/2020] [Revised: 11/20/2020] [Accepted: 11/23/2020] [Indexed: 10/22/2022]
Abstract
Endoscopy provides unique optical properties to circumvent anterior segment opacities and visualize difficult-to-access anatomical regions, including retroirideal, retrolental, ciliary body, and anterior retinal structures. We summarize the basic principles and utilization of endoscopic vitreoretinal surgery, along with recent technological advances in the field base on a structured literature search in Pubmed, Embase, and Google Scholar database up to February, 2020. Endoscopy has been used in the management of retinal detachment, ischemic retinopathies with neovascular glaucoma, severe ocular trauma, endophthalmitis, lens-related disorders in the posterior segment, pediatric vitreoretinal diseases, and implantation of retinal prostheses. Ongoing development of endoscopic technology aims to provide higher resolution images with endoscopes of smaller diameter. New surgical techniques supported by the adoption of endoscopy are available to manage challenging surgical scenarios. Endoscopy can be a useful adjunct to microscope wide-angle viewing systems in the management of complex vitreoretinal diseases.
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Affiliation(s)
| | | | - Wai Ching Lam
- Department of Ophthalmology, The University of Hong Kong, Hong Kong; Department of Ophthalmology and Vision Science, University of Toronto, Ontario, Canada
| | - Thomas C Lee
- The Vision Center, Department of Surgery, Children's Hospital Los Angeles, Los Angeles, California, USA; USC Roski Eye Institute, Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Sui Chien Wong
- Great Ormond Street Hospital for Children, London, England; National Institute for Health Research Biomedical Research Centre, Moorfields Eye Hospital & UCL Institute of Ophthalmology, London, England; Royal Free Hospital, London, England
| | - Aaron Nagiel
- The Vision Center, Department of Surgery, Children's Hospital Los Angeles, Los Angeles, California, USA; USC Roski Eye Institute, Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Robert Fung Lam
- Department of Ophthalmology, Caritas Medical Centre, Hong Kong
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Olsommer Y, Ihmig FR. Consistent and Efficient Modeling of the Nonlinear Properties of Ferroelectric Materials in Ceramic Capacitors for Frugal Electronic Implants. SENSORS (BASEL, SWITZERLAND) 2020; 20:E4206. [PMID: 32731640 PMCID: PMC7435732 DOI: 10.3390/s20154206] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 07/25/2020] [Accepted: 07/27/2020] [Indexed: 12/04/2022]
Abstract
In recent years, the development of implantable electronics has been driven by the motivation to expand their field of application. The main intention is to implement advanced functionalities while increasing the degree of miniaturization and maintaining reliability. The intrinsic nonlinear properties of the electronic components, to be used anyway, could be utilized to resolve this issue. To master the implementation of functionalities in implantable electronics using the nonlinear properties of its electronic components, simulation models are of utmost importance. In this paper, we present a simulation model that is optimized in terms of consistency, computing time and memory consumption. Three circuit topologies of nonlinear capacitors, including hysteresis losses, are investigated. An inductively coupled measurement setup was realized to validate the calculations. The best results were obtained using the Trapezoid method in ANSYS with a constant step size and a resolution of 500 k points and using the Adams method in Mathcad with a resolution of 50 k points. An inductive coupling factor between 7% and 10% leads to a significant improvement in consistency compared to lower coupling factors. Finally, our results indicate that the nonlinear properties of the voltage rectifier capacitor can be neglected since these do not significantly affect the simulation results.
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Affiliation(s)
- Yves Olsommer
- Fraunhofer Institute for Biomedical Engineering, Department of Biomedical Microsystems, 66280 Sulzbach, Saar, Germany;
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Haji Ghaffari D, Finn KE, Jeganathan VSE, Patel U, Wuyyuru V, Roy A, Weiland JD. The effect of waveform asymmetry on perception with epiretinal prostheses. J Neural Eng 2020; 17:045009. [PMID: 32590371 DOI: 10.1088/1741-2552/aba07e] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Objective Retinal prosthetic implants have helped improve vision in patients blinded by photoreceptor degeneration. Retinal implant users report improvements in light perception and performing visual tasks, but their ability to perceive shapes and letters is limited due to the low precision of retinal activation, which is exacerbated by axonal stimulation and high perceptual thresholds. A previous in vitro study in our lab used calcium imaging to measure the spatial activity of mouse retinal ganglion cells (RGCs) in response to electrical stimulation. Based on this study, symmetric anodic-first (SA) stimulation effectively avoided axonal activation and asymmetric anodic-first stimulation (AA) with duration ratios (ratio of the anodic to cathodic phase) greater than 10 reduced RGC activation thresholds significantly. Applying these novel stimulation strategies in clinic may increase perception precision and improve the overall patient outcomes. Approach We combined human subject testing and computational modeling to further examine the effect of SA and AA stimuli on perception shapes and thresholds for epiretinal stimulation of RGCs. Main results Threshold measurement in three Argus II participants indicated that AA stimulation could increase perception probabilities compared to a standard symmetric cathodic-first (SC) pulse, and this effect can be intensified by addition of an interphae gap (IPG). Our in silico RGC model predicts lower thresholds with AA and asymmetric cathodic-first (AC) stimuli compared to a SC pulse. This effect was more pronounced at shorter pulse widths. The most effective pulse for threshold reduction with short pulse durations (≤0.12 ms) was AA stimulation with small duration ratios (≤5) and long IPGs (≥2 ms). For the 0.5 ms pulse duration, SC stimulation with IPGs longer than 0.5 ms, or asymmetric stimuli with large duration ratios (≥20) were most effective in threshold reduction. Phosphene shape analysis did not reveal a significant change in percept elongation with SA stimulation. However, there was a significant increase in percept size (P < 0.01) with AA stimulation compared to the standard pulse in one participant. Significane Including asymmetric waveform capability will provide more flexible options for optimization and personalized fitting of retinal implants.
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Affiliation(s)
- Dorsa Haji Ghaffari
- Department of Biomedical Engineering, Michigan Engineering, University of Michigan, Ann Arbor, MI 48109, United States of America. Biointerfaces Institute, University of Michigan, Ann Arbor, MI 48109, United States of America
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Im M, Kim SW. Neurophysiological and medical considerations for better-performing microelectronic retinal prostheses. J Neural Eng 2020; 17:033001. [PMID: 32329755 DOI: 10.1088/1741-2552/ab8ca9] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Maesoon Im
- Center for BioMicrosystems, Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea. Division of Bio-Medical Science & Technology, KIST School, University of Science and Technology (UST), Seoul, Republic of Korea
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Shim S, Seo K, Kim SJ. A preliminary implementation of an active intraocular prosthesis as a new image acquisition device for a cortical visual prosthesis. J Artif Organs 2020; 23:262-269. [PMID: 32342231 DOI: 10.1007/s10047-020-01168-x] [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: 01/07/2020] [Accepted: 04/07/2020] [Indexed: 11/30/2022]
Abstract
An active intraocular prosthesis is herein proposed as a new image acquisition device for a cortical visual prosthesis. A conventional intraocular prosthesis is a passive device that helps blind patients underwent eye enucleation to maintain the shape of an eyeball. In contrast, an active intraocular prosthesis, which works as an implantable wireless camera, can capture real-time images and transmit them to a cortical visual prosthesis to restore partial vision of the patients. This active device has distinct advantages in that it can garner a variety of image information while focusing on objects in accordance with natural eye movements, compared with a glasses-mounted camera and implanted micro-photodiodes in typical artificial vision systems. Coated with an epoxy and sealed by an elastomer for biocompatibility as well as durability, the active intraocular prosthesis was fabricated in a spherical form miniaturized enough to be inserted into the eye. Its operation was evaluated by wireless image acquisition displaying a processed gray-scale image. Furthermore, signal-to-noise ratio measurements were conducted to find a reliable communication range of the fabricated prosthesis, while it was covered by an 8-mm-thick biological medium that mimicked in vivo environments. In conclusion, the feasibility of the active intraocular prosthesis to cooperate with a cortical visual prosthesis is discussed.
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Affiliation(s)
- Shinyong Shim
- Department of Electrical and Computer Engineering, College of Engineering, Seoul National University, Seoul, 08826, South Korea.,Inter-university Semiconductor Research Center, College of Engineering, Seoul National University, Seoul, 08826, South Korea
| | - Kangmoon Seo
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Seoul National University, Seoul, 08826, South Korea
| | - Sung June Kim
- Department of Electrical and Computer Engineering, College of Engineering, Seoul National University, Seoul, 08826, South Korea. .,Inter-university Semiconductor Research Center, College of Engineering, Seoul National University, Seoul, 08826, South Korea. .,Institute on Aging, College of Medicine, Seoul National University, Seoul, 08826, South Korea.
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Rochford AE, Carnicer-Lombarte A, Curto VF, Malliaras GG, Barone DG. When Bio Meets Technology: Biohybrid Neural Interfaces. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2020; 32:e1903182. [PMID: 31517403 DOI: 10.1002/adma.201903182] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Revised: 07/06/2019] [Indexed: 06/10/2023]
Abstract
The development of electronics capable of interfacing with the nervous system is a rapidly advancing field with applications in basic science and clinical translation. Devices containing arrays of electrodes can be used in the study of cells grown in culture or can be implanted into damaged or dysfunctional tissue to restore normal function. While devices are typically designed and used exclusively for one of these two purposes, there have been increasing efforts in developing implantable electrode arrays capable of housing cultured cells, referred to as biohybrid implants. Once implanted, the cells within these implants integrate into the tissue, serving as a mediator of the electrode-tissue interface. This biological component offers unique advantages to these implant designs, providing better tissue integration and potentially long-term stability. Herein, an overview of current research into biohybrid devices, as well as the historical background that led to their development are provided, based on the host anatomical location for which they are designed (CNS, PNS, or special senses). Finally, a summary of the key challenges of this technology and potential future research directions are presented.
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Affiliation(s)
- Amy E Rochford
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, CB3 0FA, UK
| | | | - Vincenzo F Curto
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, CB3 0FA, UK
| | - George G Malliaras
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, CB3 0FA, UK
| | - Damiano G Barone
- Electrical Engineering Division, Department of Engineering, University of Cambridge, Cambridge, CB3 0FA, UK
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, CB2 0QQ, UK
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Mutation spectrum of PRPF31, genotype-phenotype correlation in retinitis pigmentosa, and opportunities for therapy. Exp Eye Res 2020; 192:107950. [PMID: 32014492 PMCID: PMC7065041 DOI: 10.1016/j.exer.2020.107950] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 01/13/2020] [Accepted: 01/27/2020] [Indexed: 12/11/2022]
Abstract
Pathogenic variants in pre-messenger RNA (pre-mRNA) splicing factor 31, PRPF31, are the second most common genetic cause of autosomal dominant retinitis pigmentosa (adRP) in most populations. This remains a completely untreatable and incurable form of blindness, and it can be difficult to predict the clinical course of disease. In order to design appropriate targeted therapies, a thorough understanding of the genetics and molecular mechanism of this disease is required. Here, we present the structure of the PRPF31 gene and PRPF31 protein, current understanding of PRPF31 protein function and the full spectrum of all reported clinically relevant variants in PRPF31. We delineate the correlation between specific PRPF31 genotype and RP phenotype, suggesting that, except in cases of complete gene deletion or large-scale deletions, dominant negative effects contribute to phenotype as well as haploinsufficiency. This has important impacts on design of targeted therapies, particularly the feasibility of gene augmentation as a broad approach for treatment of PRPF31-associated RP. We discuss other opportunities for therapy, including antisense oligonucleotide therapy and gene-independent approaches and offer future perspectives on treatment of this form of RP. PRPF31 is the second most common cause of autosomal dominant retinitis pigmentosa and a potential target for gene therapy. We present all reported pathogenic variants in PRPF31 as a resource for clinicians, diagnostic genetics labs, and researchers. Genotype-phenotype correlations suggest that, dominant negative effects contribute to disease in addition to haploinsufficiency. This finding has important impacts on the suitability of gene augmentation approaches across all mutation types. This finding may aid prognosis of disease in PRPF31-associated RP patients.
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Nagaraj R, Bijukumar DR, Mathew B, Scott EA, Mathew MT. A review on recent advancements in ophthalmology devices: Currently in market and under clinical trials. J Drug Deliv Sci Technol 2019. [DOI: 10.1016/j.jddst.2019.04.038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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Ajlan RS, Desai AA, Mainster MA. Endoscopic vitreoretinal surgery: principles, applications and new directions. Int J Retina Vitreous 2019; 5:15. [PMID: 31236288 PMCID: PMC6580629 DOI: 10.1186/s40942-019-0165-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2018] [Accepted: 04/30/2019] [Indexed: 12/30/2022] Open
Abstract
Purpose To analyze endoscopic vitreoretinal surgery principles, applications, challenges and potential technological advances. Background Microendoscopic imaging permits vitreoretinal surgery for tissues that are not visible using operating microscopy ophthalmoscopy. Evolving instrumentation may overcome some limitations of current endoscopic technology. Analysis Transfer of the fine detail in endoscopic vitreoretinal images to extraocular video cameras is constrained currently by the caliber limitations of intraocular probes in ophthalmic surgery. Gradient index and Hopkins rod lenses provide high resolution ophthalmoscopy but restrict surgical manipulation. Fiberoptic coherent image guides offer surgical maneuverability but reduce imaging resolution. Coaxial endoscopic illumination can highlight delicate vitreoretinal structures difficult to image in chandelier or endoilluminator diffuse, side-scattered lighting. Microendoscopy’s ultra-high magnification video monitor images can reveal microscopic tissue details blurred partly by ocular media aberrations in contemporary surgical microscope ophthalmoscopy, thereby providing a lower resolution, invasive alternative to confocal fundus imaging. Endoscopic surgery is particularly useful when ocular media opacities or small pupils restrict or prevent transpupillary ophthalmoscopy. It has a growing spectrum of surgical uses that include the management of proliferative vitreoretinopathy and epiretinal membranes as well as the implantation of posterior chamber intraocular lenses and electrode arrays for intraretinal stimulation in retinitis pigmentosa. Microendoscopy’s range of applications will continue to grow with technological developments that include video microchip sensors, stereoscopic visualization, chromovitrectomy, digital image enhancement and operating room heads-up displays. Conclusion Microendoscopy is a robust platform for vitreoretinal surgery. Continuing clinical and technological innovation will help integrate it into the modern ophthalmic operating room of interconnected surgical microscopy, microendoscopy, vitrectomy machine and heads-up display instrumentation.
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Affiliation(s)
- Radwan S Ajlan
- 1Department of Ophthalmology, University of Kansas School of Medicine, 7400 State Line Road, Prairie Village, KS 66208-3444 USA
| | - Aarsh A Desai
- 2School of Medicine, University of Missouri-Kansas City, Kansas City, MO USA
| | - Martin A Mainster
- 1Department of Ophthalmology, University of Kansas School of Medicine, 7400 State Line Road, Prairie Village, KS 66208-3444 USA
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Ahn SM, Ahn J, Cha S, Yun C, Park TK, Goo YS, Kim SW. Development of a Post-vitrectomy Injection of N-methyl-N-nitrosourea as a Localized Retinal Degeneration Rabbit Model. Exp Neurobiol 2019; 28:62-73. [PMID: 30853825 PMCID: PMC6401555 DOI: 10.5607/en.2019.28.1.62] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 02/01/2019] [Accepted: 02/07/2019] [Indexed: 12/26/2022] Open
Abstract
Since genetic models for retinal degeneration (RD) in animals larger than rodents have not been firmly established to date, we sought in the present study to develop a new rabbit model of drug-induced RD. First, intravitreal injection of N-methyl-N-nitrosourea (MNU) without vitrectomy in rabbits was performed with different doses. One month after injection, morphological changes in the retinas were identified with ultra-wide-field color fundus photography (FP) and fundus autofluorescence (AF) imaging as well as spectral-domain optical coherence tomography (OCT). Notably, the degree of RD was not consistently correlated with MNU dose. Then, to check the effects of vitrectomy on MNU-induced RD, the intravitreal injection of MNU after vitrectomy in rabbits was also performed with different doses. In OCT, while there were no significant changes in the retinas for injections up to 0.1 mg (i.e., sham, 0.05 mg, and 0.1 mg), outer retinal atrophy and retinal atrophy of the whole layer were observed with MNU injections of 0.3 mg and 0.5 mg, respectively. With this outcome, 0.2 mg MNU was chosen to be injected into rabbit eyes (n=10) at two weeks after vitrectomy for further study. Six weeks after injection, morphological identification with FP, AF, OCT, and histology clearly showed localized outer RD - clearly bordered non-degenerated and degenerated outer retinal area - in all rabbits. We suggest our post-vitrectomy MNU-induced RD rabbit model could be used as an interim animal model for visual prosthetics before the transition to larger animal models.
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Affiliation(s)
- So Min Ahn
- Department of Ophthalmology, Korea University College of Medicine, Seoul 08373, Korea
| | - Jungryul Ahn
- Department of Physiology, Chungbuk National University School of Medicine, Cheongju 28644, Korea
| | - Seongkwang Cha
- Department of Physiology, Chungbuk National University School of Medicine, Cheongju 28644, Korea
| | - Cheolmin Yun
- Department of Ophthalmology, Korea University College of Medicine, Seoul 08373, Korea
| | - Tae Kwann Park
- Department of Ophthalmology, Soonchunhyang University Hospital Bucheon, Bucheon 14584, Korea
| | - Yong Sook Goo
- Department of Physiology, Chungbuk National University School of Medicine, Cheongju 28644, Korea
| | - Seong-Woo Kim
- Department of Ophthalmology, Korea University College of Medicine, Seoul 08373, Korea
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Abstract
PURPOSE OF REVIEW Retinitis pigmentosa is a group of genetically diverse inherited blinding disorders for which there are no treatments. Owing to recent advances in imaging technology, DNA sequencing, gene therapy, and stem cell biology, clinical trials have multiplied and the landscape is rapidly changing. This review provides a relevant and timely update of current trends and future directions for the diagnosis and management of this disease. RECENT FINDINGS This review will highlight the use of retinal imaging to measure progression of disease, next-generation sequencing for genetic diagnosis, the use of electronic retinal implants as well as noninvasive digital low-vision aids, and the current state of preclinical and clinical research with gene therapy and cell-based therapies. SUMMARY Retinitis pigmentosa has historically been an untreatable condition. Recent advances have allowed for limited improvement in visual outcomes for select patients. Retinal degenerative disease is on the cutting edge of regenerative medicine. Gene therapy and stem cell therapeutic strategies are currently under investigation and are expected to radically impact management of inherited retinal disease in the coming years. VIDEO ABSTRACT: http://links.lww.com/MOP/A33.
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