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Terheyden JH, Ost RAD, Behning C, Mekschrat L, Bildik G, Wintergerst MWM, Holz FG, Finger RP. Evaluation of the test-retest and inter-mode comparability of the Impact of Vision Impairment questionnaire in people with chronic eye diseases. Graefes Arch Clin Exp Ophthalmol 2024; 262:1933-1943. [PMID: 38180569 PMCID: PMC11106107 DOI: 10.1007/s00417-023-06334-4] [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] [Received: 06/14/2023] [Revised: 11/03/2023] [Accepted: 11/30/2023] [Indexed: 01/06/2024] Open
Abstract
PURPOSE The main objective of this study is to assess the test-retest and inter-administration mode reliability of the Impact of Vision Impairment profile (IVI), a common patient-reported outcome measure (PROM) for people with chronic eye diseases. METHODS The IVI was administered to adult patients with stable, chronic eye diseases two to four times per participant (average intervals between administrations 12 to 20 days; maximum two phone interviews, paper administration, electronic administration) by two trained interviewers. Rasch models were fit to the data. Intra-class correlation coefficients (ICCs), mean differences and Cronbach's alpha between test-retest administrations (two phone interviews) and inter-mode comparisons were calculated. RESULTS Two hundred-sixteen patients (mean age 67 ± 12 years, 40% male) were included in the study. The IVI met all psychometric requirements of the Rasch model, and the division into the domains of functional items (IVI_F) and emotional items (IVI_E) corresponded to the German validation study. ICCs (all for IVI_F and IVI_E, respectively) for the retest administrations were 0.938 and 0.912, and 0.853 and 0.893 for inter-mode comparisons phone/paper, 0.939 and 0.930 for phone/electronic, and 0.937 and 0.920 for paper/electronic (all p < 0.01). Mean differences (all for IVI_F and IVI_E, respectively) for the retest administrations were 2.8% and 0.7% and ranged from 2.0% to 6.2% and from 0.4 % to 4.9% between administration modes. Cronbach's alpha ranged from 0.886 to 0.944 for retest and inter-mode comparisons. CONCLUSION Due to the high test-retest reliability and the almost equally high comparability of different modes of administration of the IVI, the study endorses its use as a robust PROM to capture vision-related quality of life. Our results further support the use of the IVI as an endpoint in clinical trials and may simplify implementing it in both clinical trials or real-world evidence generation by offering multiple administration modes with high reliability.
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Affiliation(s)
- Jan Henrik Terheyden
- Department of Ophthalmology, University Hospital Bonn, Ernst-Abbe-Str. 2, 53127, Bonn, Germany.
| | - Reglind A D Ost
- Department of Ophthalmology, University Hospital Bonn, Ernst-Abbe-Str. 2, 53127, Bonn, Germany
| | - Charlotte Behning
- Department of Medical Biometry, Informatics and Epidemiology, University Hospital Bonn, Bonn, Germany
| | - Liza Mekschrat
- Department of Ophthalmology, University Hospital Bonn, Ernst-Abbe-Str. 2, 53127, Bonn, Germany
| | - Gamze Bildik
- Department of Ophthalmology, University Hospital Bonn, Ernst-Abbe-Str. 2, 53127, Bonn, Germany
| | | | - Frank G Holz
- Department of Ophthalmology, University Hospital Bonn, Ernst-Abbe-Str. 2, 53127, Bonn, Germany
| | - Robert P Finger
- Department of Ophthalmology, University Hospital Mannheim, University of Heidelberg, Mannheim, Germany.
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Stoddart PR, Begeng JM, Tong W, Ibbotson MR, Kameneva T. Nanoparticle-based optical interfaces for retinal neuromodulation: a review. Front Cell Neurosci 2024; 18:1360870. [PMID: 38572073 PMCID: PMC10987880 DOI: 10.3389/fncel.2024.1360870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2023] [Accepted: 03/04/2024] [Indexed: 04/05/2024] Open
Abstract
Degeneration of photoreceptors in the retina is a leading cause of blindness, but commonly leaves the retinal ganglion cells (RGCs) and/or bipolar cells extant. Consequently, these cells are an attractive target for the invasive electrical implants colloquially known as "bionic eyes." However, after more than two decades of concerted effort, interfaces based on conventional electrical stimulation approaches have delivered limited efficacy, primarily due to the current spread in retinal tissue, which precludes high-acuity vision. The ideal prosthetic solution would be less invasive, provide single-cell resolution and an ability to differentiate between different cell types. Nanoparticle-mediated approaches can address some of these requirements, with particular attention being directed at light-sensitive nanoparticles that can be accessed via the intrinsic optics of the eye. Here we survey the available known nanoparticle-based optical transduction mechanisms that can be exploited for neuromodulation. We review the rapid progress in the field, together with outstanding challenges that must be addressed to translate these techniques to clinical practice. In particular, successful translation will likely require efficient delivery of nanoparticles to stable and precisely defined locations in the retinal tissues. Therefore, we also emphasize the current literature relating to the pharmacokinetics of nanoparticles in the eye. While considerable challenges remain to be overcome, progress to date shows great potential for nanoparticle-based interfaces to revolutionize the field of visual prostheses.
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Affiliation(s)
- Paul R. Stoddart
- School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, VIC, Australia
| | - James M. Begeng
- School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, VIC, Australia
- Department of Biomedical Engineering, Faculty of Engineering & Information Technology, The University of Melbourne, Melbourne, VIC, Australia
| | - Wei Tong
- Department of Biomedical Engineering, Faculty of Engineering & Information Technology, The University of Melbourne, Melbourne, VIC, Australia
- School of Physics, The University of Melbourne, Melbourne, VIC, Australia
| | - Michael R. Ibbotson
- Department of Biomedical Engineering, Faculty of Engineering & Information Technology, The University of Melbourne, Melbourne, VIC, Australia
| | - Tatiana Kameneva
- School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, VIC, Australia
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Jolly JK, Grigg JR, McKendrick AM, Fujinami K, Cideciyan AV, Thompson DA, Matsumoto C, Asaoka R, Johnson C, Dul MW, Artes PH, Robson AG. ISCEV and IPS guideline for the full-field stimulus test (FST). Doc Ophthalmol 2024; 148:3-14. [PMID: 38238632 PMCID: PMC10879267 DOI: 10.1007/s10633-023-09962-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Accepted: 12/15/2023] [Indexed: 02/21/2024]
Abstract
The full-field stimulus test (FST) is a psychophysical technique designed for the measurement of visual function in low vision. The method involves the use of a ganzfeld stimulator, as used in routine full-field electroretinography, to deliver full-field flashes of light. This guideline was developed jointly by the International Society for Clinical Electrophysiology of Vision (ISCEV) and Imaging and Perimetry Society (IPS) in order to provide technical information, promote consistency of testing and reporting, and encourage convergence of methods for FST. It is intended to aid practitioners and guide the formulation of FST protocols, with a view to future standardisation.
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Affiliation(s)
- J K Jolly
- Vision and Eye Research Institute, Anglia Ruskin University, Young Street, Cambridge, CB1 2LZ, UK.
| | - J R Grigg
- Save Sight Institute, Specialty of Clinical Ophthalmology and Eye Health, Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia
- Eye Genetics Research Unit, Sydney Children's Hospitals Network, Save Sight Institute, Children's Medical Research Institute, The University of Sydney, Sydney, NSW, Australia
| | - A M McKendrick
- Lions Eye Institute, University of Western Australia, Perth, Australia
- School of Allied Health, University of Western Australia, Crawley, Australia
| | - K Fujinami
- Laboratory of Visual Physiology, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
- Institute of Ophthalmology, University College London, London, UK
| | - A V Cideciyan
- Center for Hereditary Retinal Degenerations, Scheie Eye Institute, University of Pennsylvania, Philadelphia, USA
| | - D A Thompson
- The Tony Kriss Visual Electrophysiology Unit, Clinical and Academic, Department of Ophthalmology, Sight and Sound Centre, Great Ormond Street Hospital for Children NHS Trust, London, UK
- Great Ormond Street Institute of Child Health, University College London, London, UK
| | - C Matsumoto
- Department of Ophthalmology, Kindai University, Osakasayama, Japan
| | - R Asaoka
- Department of Ophthalmology, Seirei Hamamatsu General Hospital, Hamamatsu, Shizuoka, Japan
- Seirei Christopher University, Hamamatsu, Shizuoka, Japan
- Nanovision Research Division, Research Institute of Electronics, Shizuoka University, Shizuoka, Japan
- The Graduate School for the Creation of New Photonics Industries, Shizuoka, Japan
| | - C Johnson
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa, USA
- School of Optometry, The Ohio State University, Columbus, IA, USA
| | - M W Dul
- Department of Biological and Vision Science, College of Optometry, State University of New York, New York, USA
| | - P H Artes
- Faculty of Health, University of Plymouth, Plymouth, UK
| | - A G Robson
- Institute of Ophthalmology, University College London, London, UK
- Department of Electrophysiology, Moorfields Eye Hospital, London, UK
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4
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Sadeghi R, Kartha A, Barry MP, Gibson P, Caspi A, Roy A, Geruschat DR, Dagnelie G. Benefits of thermal and distance-filtered imaging for wayfinding with prosthetic vision. Sci Rep 2024; 14:1313. [PMID: 38225344 PMCID: PMC10789760 DOI: 10.1038/s41598-024-51798-x] [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] [Received: 08/31/2023] [Accepted: 01/09/2024] [Indexed: 01/17/2024] Open
Abstract
Visual prostheses such as the Argus II provide partial vision for individuals with limited or no light perception. However, their effectiveness in daily life situations is limited by scene complexity and variability. We investigated whether additional image processing techniques could improve mobility performance in everyday indoor environments. A mobile system connected to the Argus II provided thermal or distance-filtered video stimulation. Four participants used the thermal camera to locate a person and the distance filter to navigate a hallway with obstacles. The thermal camera allowed for finding a target person in 99% of trials, while unfiltered video led to confusion with other objects and a success rate of only 55% ([Formula: see text]). Similarly, the distance filter enabled participants to detect and avoid 88% of obstacles by removing background clutter, whereas unfiltered video resulted in a detection rate of only 10% ([Formula: see text]). For any given elapsed time, the success rate with filtered video was higher than with unfiltered video. After 90 s, participants' success rate reached above 50% with filtered video and 24% and 3% with normal camera in the first and second tasks, respectively. Despite individual variations, all participants showed significant improvement when using the thermal and distance filters compared to unfiltered video. Adding a thermal and distance filter to a visual prosthesis system can enhance the performance of mobility activities by removing clutter in the background, showing people and warm objects with the thermal camera, or nearby obstacles with the distance filter.
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Affiliation(s)
- Roksana Sadeghi
- Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA.
- Herbert Wertheim School of Optometry and Vision Science, University of California, Berkeley, CA, USA.
| | - Arathy Kartha
- Department of Biological and Vision Sciences, State University of New York College of Optometry, New York, NY, USA
- Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Michael P Barry
- Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD, USA
- Pritzker Institute for Biomedical Science and Engineering, Illinois Institute of Technology, Chicago, IL, USA
| | - Paul Gibson
- Advanced Medical Electronics Corporation, Maple Grove, MN, USA
| | - Avi Caspi
- Jerusalem College of Technology, Jerusalem, Israel
| | | | - Duane R Geruschat
- Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Gislin Dagnelie
- Department of Ophthalmology, Johns Hopkins School of Medicine, Baltimore, MD, USA
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5
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de Jong PTVM. A history of visual acuity testing and optotypes. Eye (Lond) 2024; 38:13-24. [PMID: 35922542 PMCID: PMC10764321 DOI: 10.1038/s41433-022-02180-6] [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] [Received: 12/31/2021] [Revised: 06/22/2022] [Accepted: 07/08/2022] [Indexed: 11/09/2022] Open
Abstract
After going into the etymology of the word "optotype", this article covers some tasks in ancient times that required good visual acuity (VA). Around 300 BCE, Euclid formulated the existence of a visual cone with a minimal visual angle at its tip. Trials to test VA appeared AD 1754. Around that time, texts were introduced by opticians in order to be able to prescribe more reliably. In the early nineteenth century, the need for VA tests in ophthalmology resulted in German and English test charts. Numerous variants emerged after the first edition of Snellen's optotypes in 1862 in The Netherlands. However, 100 years later there was still no standard optotype to reliably test VA. Multidisciplinary approaches between ophthalmology, linguistics, psychology and psychophysics improved optotypes and VA testing, which led to the more reliable LogMAR charts. Recent advances in aids and therapies for the blind and severely visually handicapped, necessitate further development of new and standardized VA tests.
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Affiliation(s)
- Paulus T V M de Jong
- Department of Retinal Signal Processing, Netherlands Institute of Neuroscience, KNAW. Meibergdreef 47, 1105 BA, Amsterdam, The Netherlands.
- Department of Ophthalmology, AmsterdamUMC, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
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6
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Abdalla Elsayed MEA, Taylor LJ, Josan AS, Fischer MD, MacLaren RE. Choroideremia: The Endpoint Endgame. Int J Mol Sci 2023; 24:14354. [PMID: 37762657 PMCID: PMC10532430 DOI: 10.3390/ijms241814354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 08/25/2023] [Accepted: 09/09/2023] [Indexed: 09/29/2023] Open
Abstract
Choroideremia is an X-linked retinal degeneration resulting from the progressive, centripetal loss of photoreceptors and choriocapillaris, secondary to the degeneration of the retinal pigment epithelium. Affected individuals present in late childhood or early teenage years with nyctalopia and progressive peripheral visual loss. Typically, by the fourth decade, the macula and fovea also degenerate, resulting in advanced sight loss. Currently, there are no approved treatments for this condition. Gene therapy offers the most promising therapeutic modality for halting or regressing functional loss. The aims of the current review are to highlight the lessons learnt from clinical trials in choroideremia, review endpoints, and propose a future strategy for clinical trials.
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Affiliation(s)
- Maram E. A. Abdalla Elsayed
- Oxford Eye Hospital, Oxford University Hospitals National Health Service Foundation Trust, Oxford OX3 9DU, UK
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK
| | - Laura J. Taylor
- Oxford Eye Hospital, Oxford University Hospitals National Health Service Foundation Trust, Oxford OX3 9DU, UK
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK
| | - Amandeep S. Josan
- Oxford Eye Hospital, Oxford University Hospitals National Health Service Foundation Trust, Oxford OX3 9DU, UK
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK
| | - M. Dominik Fischer
- Oxford Eye Hospital, Oxford University Hospitals National Health Service Foundation Trust, Oxford OX3 9DU, UK
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK
| | - Robert E. MacLaren
- Oxford Eye Hospital, Oxford University Hospitals National Health Service Foundation Trust, Oxford OX3 9DU, UK
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK
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7
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Wang HZ, Wong YT. A novel simulation paradigm utilising MRI-derived phosphene maps for cortical prosthetic vision. J Neural Eng 2023; 20:046027. [PMID: 37531948 PMCID: PMC10594539 DOI: 10.1088/1741-2552/aceca2] [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] [Received: 11/17/2022] [Revised: 07/13/2023] [Accepted: 08/01/2023] [Indexed: 08/04/2023]
Abstract
Objective.We developed a realistic simulation paradigm for cortical prosthetic vision and investigated whether we can improve visual performance using a novel clustering algorithm.Approach.Cortical visual prostheses have been developed to restore sight by stimulating the visual cortex. To investigate the visual experience, previous studies have used uniform phosphene maps, which may not accurately capture generated phosphene map distributions of implant recipients. The current simulation paradigm was based on the Human Connectome Project retinotopy dataset and the placement of implants on the cortices from magnetic resonance imaging scans. Five unique retinotopic maps were derived using this method. To improve performance on these retinotopic maps, we enabled head scanning and a density-based clustering algorithm was then used to relocate centroids of visual stimuli. The impact of these improvements on visual detection performance was tested. Using spatially evenly distributed maps as a control, we recruited ten subjects and evaluated their performance across five sessions on the Berkeley Rudimentary Visual Acuity test and the object recognition task.Main results.Performance on control maps is significantly better than on retinotopic maps in both tasks. Both head scanning and the clustering algorithm showed the potential of improving visual ability across multiple sessions in the object recognition task.Significance.The current paradigm is the first that simulates the experience of cortical prosthetic vision based on brain scans and implant placement, which captures the spatial distribution of phosphenes more realistically. Utilisation of evenly distributed maps may overestimate the performance that visual prosthetics can restore. This simulation paradigm could be used in clinical practice when making plans for where best to implant cortical visual prostheses.
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Affiliation(s)
- Haozhe Zac Wang
- Department of Electrical and Computer Systems Engineering, Monash University, Melbourne, Australia
| | - Yan Tat Wong
- Department of Electrical and Computer Systems Engineering, Monash University, Melbourne, Australia
- Department of Physiology, Monash University, Melbourne, Australia
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8
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Palanker D. Electronic Retinal Prostheses. Cold Spring Harb Perspect Med 2023; 13:a041525. [PMID: 36781222 PMCID: PMC10411866 DOI: 10.1101/cshperspect.a041525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Retinal prostheses are a promising means for restoring sight to patients blinded by photoreceptor atrophy. They introduce visual information by electrical stimulation of the surviving inner retinal neurons. Subretinal implants target the graded-response secondary neurons, primarily the bipolar cells, which then transfer the information to the ganglion cells via the retinal neural network. Therefore, many features of natural retinal signal processing can be preserved in this approach if the inner retinal network is retained. Epiretinal implants stimulate primarily the ganglion cells, and hence should encode the visual information in spiking patterns, which, ideally, should match the target cell types. Currently, subretinal arrays are being developed primarily for restoration of central vision in patients impaired by age-related macular degeneration (AMD), while epiretinal implants-for patients blinded by retinitis pigmentosa, where the inner retina is less preserved. This review describes the concepts and technologies, preclinical characterization of prosthetic vision and clinical outcomes, and provides a glimpse into future developments.
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Affiliation(s)
- Daniel Palanker
- Department of Ophthalmology and Hansen Experimental Physics Laboratory, Stanford University, Stanford, California 94305, USA
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9
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Taylor LJ, Josan AS, Stratton I, Jolly JK, MacLaren RE. A cross-sectional study to assess the clinical utility of modern visual function assessments in patients with inherited retinal disease: a mixed methods observational study protocol. BMC Ophthalmol 2023; 23:234. [PMID: 37226218 DOI: 10.1186/s12886-023-02974-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Accepted: 05/11/2023] [Indexed: 05/26/2023] Open
Abstract
BACKGROUND Treatment options for patients with inherited retinal disease are limited, although research into novel therapies is underway. To ensure the success of future clinical trials, appropriate visual function outcome measures that can assess changes resulting from therapeutic interventions are urgently required. Rod-cone degenerations are the most common type of inherited retinal disease. Visual acuity is a standard measure but is typically preserved until late disease stages, frequently making it an unsuitable visual function marker. Alternative measures are required. This study investigates the clinical utility of a range of carefully selected visual function tests and patient reported outcome measures. The aim is to identify suitable outcome measures for future clinical trials that could be considered for regulatory approval. METHODS This cross-sectional study involves two participant groups, patients with inherited retinal disease (n = 40) and healthy controls (n = 40). The study has been designed to be flexible and run alongside NHS clinics. The study is split into two parts. Part one includes examining standard visual acuity, low luminance visual acuity, the Moorfields acuity chart visual acuity, mesopic microperimetry and three separate patient reported outcome measures. Part two involves 20 min of dark adaptation followed by two-colour scotopic microperimetry. Repeat testing will be undertaken where possible to enable repeatability analyses. A subset of patients with inherited retinal disease will be invited to participate in a semi-structured interview to gain awareness of participants' thoughts and feelings around the study and different study tests. DISCUSSION The study highlights a need for reliable and sensitive validated visual function measures that can be used in future clinical trials. This work will build on work from other studies and be used to inform an outcome measure framework for rod-cone degenerations. The study is in keeping with the United Kingdom Department of Health and Social Care research initiatives and strategies for increasing research opportunities for NHS patients as part of their NHS care. TRIAL REGISTRATION ISRCTN registry, ISRCTN24016133, Visual Function in Retinal Degeneration, registered on 18th August 2022.
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Affiliation(s)
- Laura J Taylor
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK.
| | - Amandeep S Josan
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Irene Stratton
- Centre for Statistics in Medicine, University of Oxford, Oxford, UK
| | - Jasleen K Jolly
- Vision and Eye Research Institute, Anglia Ruskin University, Cambridge, UK
| | - Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
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Cehajic-Kapetanovic J, Singh MS, Zrenner E, MacLaren RE. Bioengineering strategies for restoring vision. Nat Biomed Eng 2023; 7:387-404. [PMID: 35102278 DOI: 10.1038/s41551-021-00836-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 11/30/2021] [Indexed: 12/15/2022]
Abstract
Late-stage retinal degenerative disease involving photoreceptor loss can be treated by optogenetic therapy, cell transplantation and retinal prostheses. These approaches aim to restore light sensitivity to the retina as well as visual perception by integrating neuronal responses for transmission to the cortex. In age-related macular degeneration, some cell-based therapies also aim to restore photoreceptor-supporting tissue to prevent complete photoreceptor loss. In the earlier stages of degeneration, gene-replacement therapy could attenuate retinal-disease progression and reverse loss of function. And gene-editing strategies aim to correct the underlying genetic defects. In this Review, we highlight the most promising gene therapies, cell therapies and retinal prostheses for the treatment of retinal disease, discuss the benefits and drawbacks of each treatment strategy and the factors influencing whether functional tissue is reconstructed and repaired or replaced with an electronic device, and summarize upcoming technologies for enhancing the restoration of vision.
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Affiliation(s)
- Jasmina Cehajic-Kapetanovic
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, UK.
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK.
| | | | - Eberhart Zrenner
- Institute for Ophthalmic Research, Center for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford, UK
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
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11
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Kartha A, Sadeghi R, Bradley C, Tran C, Gee W, Dagnelie G. Measuring visual information gathering in individuals with ultra low vision using virtual reality. Sci Rep 2023; 13:3143. [PMID: 36823360 PMCID: PMC9950080 DOI: 10.1038/s41598-023-30249-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 02/20/2023] [Indexed: 02/25/2023] Open
Abstract
People with ULV (visual acuity ≤ 20/1600 or 1.9 logMAR) lack form vision but have rudimentary levels of vision that can be used for a range of activities in daily life. However, current clinical tests are designed to assess form vision and do not provide information about the range of visually guided activities that can be performed in daily life using ULV. This is important to know given the growing number of clinical trials that recruit individuals with ULV (e.g., gene therapy, stem cell therapy) or restore vision to the ULV range in the blind (visual prosthesis). In this study, we develop a set of 19 activities (items) in virtual reality involving spatial localization/detection, motion detection, and direction of motion that can be used to assess visual performance in people with ULV. We estimated measures of item difficulty and person ability on a relative d prime (d') axis using a signal detection theory based analysis for latent variables. The items represented a range of difficulty levels (- 1.09 to 0.39 in relative d') in a heterogeneous group of individuals with ULV (- 0.74 to 2.2 in relative d') showing the instrument's utility as an outcome measure in clinical trials.
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Affiliation(s)
- Arathy Kartha
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - Roksana Sadeghi
- Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Chris Bradley
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Chau Tran
- BaltiVirtual Inc., Baltimore, MD, USA
| | - Will Gee
- BaltiVirtual Inc., Baltimore, MD, USA
| | - Gislin Dagnelie
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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12
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Spencer M, Kameneva T, Grayden DB, Burkitt AN, Meffin H. Quantifying visual acuity for pre-clinical testing of visual prostheses. J Neural Eng 2023; 20. [PMID: 36270430 DOI: 10.1088/1741-2552/ac9c95] [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: 05/26/2022] [Accepted: 10/21/2022] [Indexed: 01/31/2023]
Abstract
Objective.Visual prostheses currently restore only limited vision. More research and pre-clinical work are required to improve the devices and stimulation strategies that are used to induce neural activity that results in visual perception. Evaluation of candidate strategies and devices requires an objective way to convert measured and modelled patterns of neural activity into a quantitative measure of visual acuity.Approach.This study presents an approach that compares evoked patterns of neural activation with target and reference patterns. A d-prime measure of discriminability determines whether the evoked neural activation pattern is sufficient to discriminate between the target and reference patterns and thus provides a quantified level of visual perception in the clinical Snellen and MAR scales. The magnitude of the resulting value was demonstrated using scaled standardized 'C' and 'E' optotypes.Main results.The approach was used to assess the visual acuity provided by two alternative stimulation strategies applied to simulated retinal implants with different electrode pitch configurations and differently sized spreads of neural activity. It was found that when there is substantial overlap in neural activity generated by different electrodes, an estimate of acuity based only upon electrode pitch is incorrect; our proposed method gives an accurate result in both circumstances.Significance.Quantification of visual acuity using this approach in pre-clinical development will allow for more rapid and accurate prototyping of improved devices and neural stimulation strategies.
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Affiliation(s)
- Martin Spencer
- Department of Biomedical Engineering, The University of Melbourne, Parkville, Victoria, Australia.,Greame Clark Institute of Biomedical Engineering, The University of Melbourne, Parkville, Victoria, Australia
| | - Tatiana Kameneva
- Department of Biomedical Engineering, The University of Melbourne, Parkville, Victoria, Australia.,School of Science, Computing and Engineering Technologies, Swinburne University of Technology, Hawthorn, Victoria, Australia
| | - David B Grayden
- Department of Biomedical Engineering, The University of Melbourne, Parkville, Victoria, Australia.,Greame Clark Institute of Biomedical Engineering, The University of Melbourne, Parkville, Victoria, Australia
| | - Anthony N Burkitt
- Department of Biomedical Engineering, The University of Melbourne, Parkville, Victoria, Australia.,Greame Clark Institute of Biomedical Engineering, The University of Melbourne, Parkville, Victoria, Australia
| | - Hamish Meffin
- Department of Biomedical Engineering, The University of Melbourne, Parkville, Victoria, Australia.,Greame Clark Institute of Biomedical Engineering, The University of Melbourne, Parkville, Victoria, Australia.,National Vision Research Institute, Australian College of Optometry, Carlton, Victoria, Australia
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13
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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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14
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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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15
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Avraham D, Yitzhaky Y. Simulating the perceptual effects of electrode-retina distance in prosthetic vision. J Neural Eng 2022; 19. [PMID: 35561665 DOI: 10.1088/1741-2552/ac6f82] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 05/13/2022] [Indexed: 11/12/2022]
Abstract
OBJECTIVE Retinal prostheses aim to restore some vision in retinitis pigmentosa and age-related macular degeneration blind patients. Many spatial and temporal aspects have been found to affect prosthetic vision. Our objective is to study the impact of the space-variant distance between the stimulating electrodes and the surface of the retina on prosthetic vision and how to mitigate this impact. APPROACH A prosthetic vision simulation was built to demonstrate the perceptual effects of the electrode-retina distance (ERD) with different random spatial variations, such as size, brightness, shape, dropout, and spatial shifts. Three approaches for reducing the ERD effects are demonstrated: electrode grouping (quads), ERD-based input-image enhancement, and object scanning with and without phosphene persistence. A quantitative assessment for the first two approaches was done based on experiments with 20 subjects and three vision-based computational image similarity metrics. MAIN RESULTS The effects of various ERDs on phosphenes' size, brightness, and shape were simulated. Quads, chosen according to the ERDs, effectively elicit phosphenes without exceeding the safe charge density limit, whereas single electrodes with large ERD cannot do so. Input-image enhancement reduced the ERD effects effectively. These two approaches significantly improved ERD-affected prosthetic vision according to the experiment and image similarity metrics. A further reduction of the ERD effects was achieved by scanning an object while moving the head. SIGNIFICANCE ERD has multiple effects on perception with retinal prostheses. One of them is vision loss caused by the incapability of electrodes with large ERD to evoke phosphenes. The three approaches presented in this study can be used separately or together to mitigate the impact of ERD. A consideration of our approaches in reducing the perceptual effects of the ERD may help improve the perception with current prosthetic technology and influence the design of future prostheses.
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Affiliation(s)
- David Avraham
- Department of Electro-Optical Engineering, Ben-Gurion University of the Negev, 1 Ben-Gurion Blvd., Beer-Sheva, 84105, ISRAEL
| | - Yitzhak Yitzhaky
- Electro-Optical Engineering, School of Engineering, Ben-Gurion University of the Negev, 1 Ben-Gurion Blvd., Beer-Sheva, Southern, 84105, ISRAEL
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16
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Sharf T, Kalakuntla T, J Lee D, Gokoffski KK. Electrical devices for visual restoration. Surv Ophthalmol 2022; 67:793-800. [PMID: 34487742 PMCID: PMC9241872 DOI: 10.1016/j.survophthal.2021.08.008] [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] [Received: 03/25/2021] [Revised: 08/24/2021] [Accepted: 08/30/2021] [Indexed: 11/21/2022]
Abstract
Given the rising number of patients with blindness from macular, optic nerve, and visual pathway disease, there is considerable interest in the potential of electrical stimulation devices to restore vision. Electrical devices for restoration of visual function can be grouped into three categories: (1) visual prostheses whose goal is to bypass damaged areas and directly activate downstream intact portions of the visual pathway; (2) electric field stimulation whose goal is to activate endogenous transcriptional and molecular signaling pathways to promote neuroprotection and neuro-regeneration; and (3) neuromodulation whose stimulation would resuscitate neural circuits vital to coordinating responses to visual input. In this review, we discuss these three approaches, describe advances made in the different fields, and comment on limitations and potential future directions.
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Affiliation(s)
- Tamara Sharf
- Keck School of Medicine, University of Southern California, CA, USA
| | - Tej Kalakuntla
- Keck School of Medicine, University of Southern California, CA, USA
| | - Darrin J Lee
- Department of Neurological Surgery, University of Southern California, CA, USA
| | - Kimberly K Gokoffski
- Department of Ophthalmology, Roski Eye Institute, University of Southern California, CA, USA.
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17
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Liu Z, Ayton LN, O'Hare F, Arslan J, Hu ML, Noar AP, Wang JH, Hickey DG, McGuinness MB, Vincent AL, Chen FK, Edwards TL. Intereye Symmetry in Bietti Crystalline Dystrophy. Am J Ophthalmol 2022; 235:313-325. [PMID: 34283985 DOI: 10.1016/j.ajo.2021.07.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 06/07/2021] [Accepted: 07/09/2021] [Indexed: 11/01/2022]
Abstract
PURPOSE To evaluate anatomic and functional intereye symmetry among individuals with Bietti crystalline dystrophy (BCD) using clinical and multimodal imaging methods, with a focus on the number, area, and distribution of the characteristic retinal crystalline deposits. DESIGN Observational case series with prospective and retrospective data. METHODS Setting: Multicenter. STUDY POPULATION Thirteen Australian and New Zealand participants (26 eyes) with confirmed biallelic CYP4V2 mutations and a characteristic BCD fundus appearance. Procedures and main outcome measures: Crystals visible on color fundus photography were manually counted. Crystals were superimposed on aligned multimodal fundus images. Spearman's correlation coefficients (ρ), intraclass correlation coefficients (ICCs), and Bland-Altman plots were used to quantify symmetry between eyes. MAIN OUTCOME MEASURES Fundus crystal area and count, and absent-autofluorescence (absent-AF) area. RESULTS Median participant age was 48 years (interquartile range: 40-60 years). Intereye symmetry was high for fundus crystal area (ρ = 1.00, 95% confidence interval [CI]: 1.00-1.00; ICC = 0.97, 95% CI: 0.88-0.99), fundus crystal count (ρ = 0.98, 95% CI: 0.92-1.00; ICC = 0.97, 95% CI: 0.89-0.99), and absent-AF area (ρ = 0.88, 95% CI: 0.53-0.98; ICC = 0.98, 95% CI: 0.90-0.99). Average foveal volume, foveal crystal count and area, average and central foveal thickness, best corrected visual acuity, and average macular and central foveal sensitivity were not highly correlated between eyes. CONCLUSIONS This study demonstrated strong intereye symmetry measured by fundus crystal area, fundus crystal number, and absent-AF area. This may influence the choice of outcome measures for future therapeutic trials for BCD and provides valuable clinical information for ophthalmologists involved in the care and counseling of patients with BCD.
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18
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Britten‐Jones AC, O'Hare F, Edwards TL, Ayton LN. Victorian evolution of inherited retinal diseases natural history registry (VENTURE study): Rationale, methodology and initial participant characteristics. Clin Exp Ophthalmol 2022; 50:768-780. [PMID: 35621151 PMCID: PMC9796389 DOI: 10.1111/ceo.14110] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 04/28/2022] [Accepted: 05/15/2022] [Indexed: 01/01/2023]
Abstract
BACKGROUND Emerging treatments are being developed for inherited retinal diseases, requiring a clear understanding of natural progression and a database of potential participants for clinical trials. This article describes the rationale, study design and methodology of the Victorian Evolution of inherited retinal diseases NaTUral history REgistry (VENTURE), including data from the first 150 participants enrolled. METHODS VENTURE collects retrospective and prospective data from people with inherited retinal diseases. Following registration, participants are asked to attend a baseline examination using a standardised protocol to confirm their inherited retinal disease diagnosis. Examination procedures include (i) retinal function, using visual acuity and perimetry; (ii) retinal structure, using multimodal imaging and (iii) patient-reported outcomes. Participants' molecular diagnoses are obtained from their clinical records or through targeted-panel genetic testing by an independent laboratory. Phenotype and genotype data are used to enrol participants into disease-specific longitudinal cohort sub-studies. RESULTS From 7 July 2020 to 30 December 2021, VENTURE enrolled 150 registrants (138 families) and most (63%) have a rod-cone dystrophy phenotype. From 93 participants who have received a probable molecular diagnosis, the most common affected genes are RPGR (13% of all registrants), USH2A (10%), CYP4V2 (7%), ABCA4 (5%), and CHM (5%). Most participants have early to moderate vision impairment, with over half (55%) having visual acuities of better than 6/60 (20/200) at registration. CONCLUSIONS The VENTURE study will complement existing patient registries and help drive inherited retinal disease research in Australia, facilitating access to research opportunities for individuals with inherited retinal diseases.
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Affiliation(s)
- Alexis Ceecee Britten‐Jones
- Department of Optometry and Vision Sciences, Faculty of Medicine, Dentistry and Health SciencesUniversity of MelbourneParkvilleAustralia,Department of Surgery (Ophthalmology), Faculty of Medicine, Dentistry and Health SciencesUniversity of MelbourneParkvilleAustralia,Centre for Eye Research AustraliaRoyal Victorian Eye and Ear HospitalMelbourneAustralia
| | - Fleur O'Hare
- Department of Optometry and Vision Sciences, Faculty of Medicine, Dentistry and Health SciencesUniversity of MelbourneParkvilleAustralia,Department of Surgery (Ophthalmology), Faculty of Medicine, Dentistry and Health SciencesUniversity of MelbourneParkvilleAustralia,Centre for Eye Research AustraliaRoyal Victorian Eye and Ear HospitalMelbourneAustralia
| | - Thomas L. Edwards
- Department of Surgery (Ophthalmology), Faculty of Medicine, Dentistry and Health SciencesUniversity of MelbourneParkvilleAustralia,Centre for Eye Research AustraliaRoyal Victorian Eye and Ear HospitalMelbourneAustralia
| | - Lauren N. Ayton
- Department of Optometry and Vision Sciences, Faculty of Medicine, Dentistry and Health SciencesUniversity of MelbourneParkvilleAustralia,Department of Surgery (Ophthalmology), Faculty of Medicine, Dentistry and Health SciencesUniversity of MelbourneParkvilleAustralia,Centre for Eye Research AustraliaRoyal Victorian Eye and Ear HospitalMelbourneAustralia
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19
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Britten-Jones AC, Jin R, Gocuk SA, Cichello E, O'Hare F, Hickey DG, Edwards TL, Ayton LN. The safety and efficacy of gene therapy treatment for monogenic retinal and optic nerve diseases: A systematic review. Genet Med 2021; 24:521-534. [PMID: 34906485 DOI: 10.1016/j.gim.2021.10.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 09/17/2021] [Accepted: 10/21/2021] [Indexed: 02/08/2023] Open
Abstract
PURPOSE This study aimed to systematically review and summarize gene therapy treatment for monogenic retinal and optic nerve diseases. METHODS This review was prospectively registered (CRD42021229812). A comprehensive literature search was performed in Ovid MEDLINE, Ovid Embase, Cochrane Central, and clinical trial registries (February 2021). Clinical studies describing DNA-based gene therapy treatments for monogenic posterior ocular diseases were eligible for inclusion. Risk of bias evaluation was performed. Data synthesis was undertaken applying Synthesis Without Meta-analysis guidelines. RESULTS This study identified 47 full-text publications, 50 conference abstracts, and 54 clinical trial registry entries describing DNA-based ocular gene therapy treatments for 16 different genetic variants. Study summaries and visual representations of safety and efficacy outcomes are presented for 20 unique full-text publications in RPE65-mediated retinal dystrophies, choroideremia, Leber hereditary optic neuropathy, rod-cone dystrophy, achromatopsia, and X-linked retinoschisis. The most common adverse events were related to lid/ocular surface/cornea abnormalities in subretinal gene therapy trials and anterior uveitis in intravitreal gene therapy trials. CONCLUSION There is a high degree of variability in ocular monogenic gene therapy trials with respect to study design, statistical methodology, and reporting of safety and efficacy outcomes. This review improves the accessibility and transparency in interpreting gene therapy trials to date.
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Affiliation(s)
- Alexis Ceecee Britten-Jones
- Department of Optometry and Vision Sciences, Melbourne School of Health Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Victoria, Australia; Department of Surgery (Ophthalmology), Melbourne Medical School, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Victoria, Australia; Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia.
| | - Rui Jin
- Department of Optometry and Vision Sciences, Melbourne School of Health Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Victoria, Australia
| | - Sena A Gocuk
- Department of Optometry and Vision Sciences, Melbourne School of Health Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Victoria, Australia; Department of Surgery (Ophthalmology), Melbourne Medical School, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Victoria, Australia; Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
| | - Elise Cichello
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
| | - Fleur O'Hare
- Department of Optometry and Vision Sciences, Melbourne School of Health Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Victoria, Australia; Department of Surgery (Ophthalmology), Melbourne Medical School, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Victoria, Australia; Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
| | - Doron G Hickey
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
| | - Thomas L Edwards
- Department of Surgery (Ophthalmology), Melbourne Medical School, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Victoria, Australia; Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
| | - Lauren N Ayton
- Department of Optometry and Vision Sciences, Melbourne School of Health Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Victoria, Australia; Department of Surgery (Ophthalmology), Melbourne Medical School, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, Victoria, Australia; Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
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20
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Roman AJ, Cideciyan AV, Wu V, Garafalo AV, Jacobson SG. Full-field stimulus testing: Role in the clinic and as an outcome measure in clinical trials of severe childhood retinal disease. Prog Retin Eye Res 2021; 87:101000. [PMID: 34464742 DOI: 10.1016/j.preteyeres.2021.101000] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 08/24/2021] [Accepted: 08/27/2021] [Indexed: 12/27/2022]
Abstract
Disease mechanisms have become better understood in previously incurable forms of early-onset severe retinal dystrophy, such as Leber congenital amaurosis (LCA). This has led to novel treatments and clinical trials that have shown some success. Standard methods to measure vision were difficult if not impossible to perform in severely affected patients with low vision and nystagmus. To meet the need for visual assays, we devised a psychophysical method, which we named full-field stimulus testing (FST). From early versions based on an automated perimeter, we advanced FST to a more available light-emitting diode platform. The journey from invention to use of such a technique in our inherited retinal degeneration clinic is reviewed and many of the lessons learned over the 15 years of application of FST are explained. Although the original purpose and application of FST was to quantify visual thresholds in LCA, there are rare opportunities for FST also to be used beyond LCA to measure aspects of vision in other inherited retinal degenerations; examples are given. The main goal of the current review, however, remains to enable investigators studying and treating LCA to understand how to best use FST and how to reduce artefact and confounding complexities so the test results become more valuable to the understanding of LCA diseases and results of novel interventions.
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Affiliation(s)
- Alejandro J Roman
- Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Artur V Cideciyan
- Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Vivian Wu
- Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Alexandra V Garafalo
- Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Samuel G Jacobson
- Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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21
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Avraham D, Jung JH, Yitzhaky Y, Peli E. Retinal prosthetic vision simulation: temporal aspects. J Neural Eng 2021; 18. [PMID: 34359062 DOI: 10.1088/1741-2552/ac1b6c] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 08/06/2021] [Indexed: 11/11/2022]
Abstract
Objective. The perception of individuals fitted with retinal prostheses is not fully understood, although several retinal implants have been tested and commercialized. Realistic simulations of perception with retinal implants would be useful for future development and evaluation of such systems.Approach.We implemented a retinal prosthetic vision simulation, including temporal features, which have not been previously simulated. In particular, the simulation included temporal aspects such as persistence and perceptual fading of phosphenes and the electrode activation rate.Main results.The simulated phosphene persistence showed an effective reduction in flickering at low electrode activation rates. Although persistence has a positive effect on static scenes, it smears dynamic scenes. Perceptual fading following continuous stimulation affects prosthetic vision of both static and dynamic scenes by making them disappear completely or partially. However, we showed that perceptual fading of a static stimulus might be countered by head-scanning motions, which together with the persistence revealed the contours of the faded object. We also showed that changing the image polarity may improve simulated prosthetic vision in the presence of persistence and perceptual fading.Significance.Temporal aspects have important roles in prosthetic vision, as illustrated by the simulations. Considering these aspects may improve the future design, the training with, and evaluation of retinal prostheses.
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Affiliation(s)
- David Avraham
- Department of Electro-Optical Engineering, School of Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel.,Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, United States of America
| | - Jae-Hyun Jung
- Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, United States of America
| | - Yitzhak Yitzhaky
- Department of Electro-Optical Engineering, School of Electrical and Computer Engineering, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Eli Peli
- Schepens Eye Research Institute of Massachusetts Eye and Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, United States of America
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22
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Hallum LE, Dakin SC. Retinal Implantation of Electronic Vision Prostheses to Treat Retinitis Pigmentosa: A Systematic Review. Transl Vis Sci Technol 2021; 10:8. [PMID: 34383874 PMCID: PMC8362638 DOI: 10.1167/tvst.10.10.8] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Purpose Retinitis pigmentosa (RP) is a hereditary disease causing photoreceptor degeneration and permanent vision loss. Retinal implantation of a stimulating electrode array is a new treatment for RP, but quantification of its efficacy is the subject of ongoing work. This review evaluates vision-related outcomes resulting from retinal implantation in participants with RP. Methods We searched MEDLINE and Embase for journal articles published since January 1, 2015. We selected articles describing studies of implanted participants that reported the postimplantation measurement of vision. We extracted study information including design, participants’ residual vision, comparators, and assessed outcomes. To assess the risk of bias, we used signaling questions and a target trial. Results Our search returned 425 abstracts. We reviewed the full text of 34 articles. We judged all studies to be at high risk of bias owing to the study design or experimental conduct. Regarding design, studies lacked the measures that typical clinical trials take to protect against bias (e.g., control groups and masking). Regarding experimental conduct, outcome measures were rarely comparable before and after implantation, and psychophysical methods were prone to bias (subjective, not forced choice, methods). The most common comparison found was between postimplantation visual function with the device powered off versus on. This comparison is at high risk of bias. Conclusions There is a need for high-quality evidence of efficacy of retinal implantation to treat RP. Translational Relevance For patients and clinicians to make informed choices about RP treatment, visual function restored by retinal implantation must be properly quantified and reported.
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Affiliation(s)
- Luke E Hallum
- Department of Mechanical Engineering, University of Auckland, Auckland, New Zealand
| | - Steven C Dakin
- School of Optometry and Vision Science, University of Auckland, Auckland, New Zealand
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23
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Karapanos L, Abbott CJ, Ayton LN, Kolic M, McGuinness MB, Baglin EK, Titchener SA, Kvansakul J, Johnson D, Kentler WG, Barnes N, Nayagam DAX, Allen PJ, Petoe MA. Functional Vision in the Real-World Environment With a Second-Generation (44-Channel) Suprachoroidal Retinal Prosthesis. Transl Vis Sci Technol 2021; 10:7. [PMID: 34383875 PMCID: PMC8362639 DOI: 10.1167/tvst.10.10.7] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 06/09/2021] [Indexed: 11/24/2022] Open
Abstract
Purpose In a clinical trial (NCT03406416) of a second-generation (44-channel) suprachoroidal retinal prosthesis implanted in subjects with late-stage retinitis pigmentosa (RP), we assessed performance in real-world functional visual tasks and emotional well-being. Methods The Functional Low-Vision Observer Rated Assessment (FLORA) and Impact of Vision Impairment-Very Low Vision (IVI-VLV) instruments were administered to four subjects before implantation and after device fitting. The FLORA contains 13 self-reported and 35 observer-reported items ranked for ease of conducting task (impossible-easy, central tendency given as mode). The IVI-VLV instrument quantified the impact of low vision on daily activities and emotional well-being. Results Three subjects completed the FLORA for two years after device fitting; the fourth subject ceased participation in the FLORA after fitting for reasons unrelated to the device. For all subjects at each post-fitting visit, the mode ease of task with device ON was better or equal to device OFF. Ease of task improved over the first six months with device ON, then remained stable. Subjects reported improvements in mobility, functional vision, and quality of life with device ON. The IVI-VLV suggested self-assessed vision-related quality of life was not impacted by device implantation or usage. Conclusions Subjects demonstrated sustained improved ease of task scores with device ON compared to OFF, indicating the device has a positive impact in the real-world setting. Translational Relevance Our suprachoroidal retinal prosthesis shows potential utility in everyday life, by enabling an increased environmental awareness and improving access to sensory information for people with end-stage RP.
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Affiliation(s)
- Lewis Karapanos
- Centre for Eye Research Australia, Royal Victorian Eye & Ear Hospital, East Melbourne, VIC, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, East Melbourne, VIC, Australia
| | - Carla J. Abbott
- Centre for Eye Research Australia, Royal Victorian Eye & Ear Hospital, East Melbourne, VIC, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, East Melbourne, VIC, Australia
| | - Lauren N. Ayton
- Centre for Eye Research Australia, Royal Victorian Eye & Ear Hospital, East Melbourne, VIC, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, East Melbourne, VIC, Australia
- Department of Optometry and Vision Sciences, University of Melbourne, Melbourne, VIC, Australia
| | - Maria Kolic
- Centre for Eye Research Australia, Royal Victorian Eye & Ear Hospital, East Melbourne, VIC, Australia
| | - Myra B. McGuinness
- Centre for Eye Research Australia, Royal Victorian Eye & Ear Hospital, East Melbourne, VIC, Australia
- Melbourne School of Population and Global Health, University of Melbourne, Parkville, VIC, Australia
| | - Elizabeth K. Baglin
- Centre for Eye Research Australia, Royal Victorian Eye & Ear Hospital, East Melbourne, VIC, Australia
| | - Samuel A. Titchener
- Bionics Institute, East Melbourne, VIC, Australia
- Medical Bionics Department, University of Melbourne, Parkville, VIC, Australia
| | - Jessica Kvansakul
- Bionics Institute, East Melbourne, VIC, Australia
- Medical Bionics Department, University of Melbourne, Parkville, VIC, Australia
| | - Dean Johnson
- Specialised Orientation and Mobility, Melbourne, VIC, Australia
| | - William G. Kentler
- Department of Biomedical Engineering, University of Melbourne, Parkville, VIC, Australia
| | - Nick Barnes
- Research School of Engineering, Australian National University, Canberra, ACT, Australia
| | - David A. X. Nayagam
- Bionics Institute, East Melbourne, VIC, Australia
- Department of Pathology, University of Melbourne, St. Vincent's Hospital, Fitzroy, VIC, Australia
| | - Penelope J. Allen
- Centre for Eye Research Australia, Royal Victorian Eye & Ear Hospital, East Melbourne, VIC, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, East Melbourne, VIC, Australia
| | - Matthew A. Petoe
- Bionics Institute, East Melbourne, VIC, Australia
- Medical Bionics Department, University of Melbourne, Parkville, VIC, Australia
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Petoe MA, Titchener SA, Kolic M, Kentler WG, Abbott CJ, Nayagam DAX, Baglin EK, Kvansakul J, Barnes N, Walker JG, Epp SB, Young KA, Ayton LN, Luu CD, Allen PJ. A Second-Generation (44-Channel) Suprachoroidal Retinal Prosthesis: Interim Clinical Trial Results. Transl Vis Sci Technol 2021; 10:12. [PMID: 34581770 PMCID: PMC8479573 DOI: 10.1167/tvst.10.10.12] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To report the initial safety and efficacy results of a second-generation (44-channel) suprachoroidal retinal prosthesis at 56 weeks after device activation. Methods Four subjects, with advanced retinitis pigmentosa and bare-light perception only, enrolled in a phase II trial (NCT03406416). A 44-channel electrode array was implanted in a suprachoroidal pocket. Device stability, efficacy, and adverse events were investigated at 12-week intervals. Results All four subjects were implanted successfully and there were no device-related serious adverse events. Color fundus photography indicated a mild postoperative subretinal hemorrhage in two recipients, which cleared spontaneously within 2 weeks. Optical coherence tomography confirmed device stability and position under the macula. Screen-based localization accuracy was significantly better for all subjects with device on versus device off. Two subjects were significantly better with the device on in a motion discrimination task at 7, 15, and 30°/s and in a spatial discrimination task at 0.033 cycles per degree. All subjects were more accurate with the device on than device off at walking toward a target on a modified door task, localizing and touching tabletop objects, and detecting obstacles in an obstacle avoidance task. A positive effect of the implant on subjects' daily lives was confirmed by an orientation and mobility assessor and subject self-report. Conclusions These interim study data demonstrate that the suprachoroidal prosthesis is safe and provides significant improvements in functional vision, activities of daily living, and observer-rated quality of life. Translational Relevance A suprachoroidal prosthesis can provide clinically useful artificial vision while maintaining a safe surgical profile.
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Affiliation(s)
- Matthew A Petoe
- Bionics Institute, East Melbourne, Victoria, Australia.,Medical Bionics Department, University of Melbourne, Melbourne, Victoria, Australia
| | - Samuel A Titchener
- Bionics Institute, East Melbourne, Victoria, Australia.,Medical Bionics Department, University of Melbourne, Melbourne, Victoria, Australia
| | - Maria Kolic
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
| | - William G Kentler
- Department of Biomedical Engineering, University of Melbourne, Melbourne, Victoria, Australia
| | - Carla J Abbott
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia.,Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia
| | - David A X Nayagam
- Bionics Institute, East Melbourne, Victoria, Australia.,Department of Pathology, University of Melbourne, St. Vincent's Hospital, Victoria, Australia
| | - Elizabeth K Baglin
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
| | - Jessica Kvansakul
- Bionics Institute, East Melbourne, Victoria, Australia.,Medical Bionics Department, University of Melbourne, Melbourne, Victoria, Australia
| | - Nick Barnes
- Research School of Engineering, Australian National University, Canberra, Australian Capital Territory, Australia
| | - Janine G Walker
- Research School of Engineering, Australian National University, Canberra, Australian Capital Territory, Australia.,Health & Biosecurity, CSIRO, Canberra, Australian Capital Territory, Australia
| | | | - Kiera A Young
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
| | - Lauren N Ayton
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia.,Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia.,Department of Optometry and Vision Sciences, University of Melbourne, Australia
| | - Chi D Luu
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia.,Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia
| | - Penelope J Allen
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia.,Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia
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25
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Allen PJ. Retinal prostheses: Where to from here? Clin Exp Ophthalmol 2021; 49:418-429. [PMID: 34021959 DOI: 10.1111/ceo.13950] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 05/05/2021] [Accepted: 05/09/2021] [Indexed: 11/29/2022]
Abstract
Researchers have been working towards the development of retinal prostheses, so called "bionic eyes" since the 1960s in an effort to restore functional vision to severely visually impaired patients. Groups from all around the world are involved in this research but in particular, groups from the United States, Germany, France, Japan and Australia have conducted clinical trials of these devices and three of these devices have achieved either FDA HDE (U.S. Food and Drug Administration Humanitarian Device Exception) or CE mark approval for commercial production. Despite this, all three of these devices are now not in commercial production. There are many challenges to overcome to develop devices suitable to implant in human patients and then reach commercial distribution. This is an exacting process and many hurdles need to be overcome to reach this point so that leaving the market after achieving this goal is a significant decision. Ongoing research is exploring the possibility of less complicated surgery with better visual processing algorithms to provide more useful visual information for our patients to provide a commercial alternative.
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Affiliation(s)
- Penelope J Allen
- The Centre for Eye Research Australia, East Melbourne, Australia.,Department of Surgery (Ophthalmology), University of Melbourne, Melbourne, Australia.,The Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
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26
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Tuohy GP, Megaw R. A Systematic Review and Meta-Analyses of Interventional Clinical Trial Studies for Gene Therapies for the Inherited Retinal Degenerations (IRDs). Biomolecules 2021; 11:760. [PMID: 34069580 PMCID: PMC8160708 DOI: 10.3390/biom11050760] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 05/04/2021] [Accepted: 05/08/2021] [Indexed: 12/13/2022] Open
Abstract
IRDs are one of the leading causes of visual loss in children and young adults. Mutations in over 271 genes lead to retinal dysfunction, degeneration and sight loss. Though no cure exists, gene augmentation therapy has brought hope to the field. This systematic review sought to assess the efficacy of available gene therapy treatments for IRDs. Databases and public resources were searched for randomised controlled trials (RCTs) and non-randomised studies of interventions (NRSIs). Standard methodological procedures were used, including a risk-of-bias assessment. One RCT and five NRSIs were assessed, all for adeno-associated virus two (AAV2)-mediated treatment of RPE-specific 65 kDa (RPE65)-associated LCA (Leber congenital amaurosis). Five outcomes were reported for meta-analyses. Modest improvements in visual acuity, ambulatory navigation/mobility testing or central retinal thickness was observed. There was significant improvement in red and blue light full-field stimulus testing (FST) (red light risk ratio of 1.89, treated v control, p = 0.04; and blue light risk ratio of 2.01, treated v control, p = 0.001). Study design assessment using a ROBIN-I tool (Cochrane Library) showed risk-of-bias judgement to be "low/moderate", whilst there were "some concerns" for the RCT using a RoB-2 tool (Cochrane Library). Although comparison by meta-analysis is compromised by, amongst other issues, a variable amount of vector delivered in each trial, FST improvements demonstrate a proof-of-principle for treating IRDs with gene therapy.
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Affiliation(s)
- Gearóid P. Tuohy
- MRC Human Genetics Unit, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK;
| | - Roly Megaw
- MRC Human Genetics Unit, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK;
- Princess Alexandra Eye Pavilion, NHS Lothian, Edinburgh EH3 9HA, UK
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What do blind people "see" with retinal prostheses? Observations and qualitative reports of epiretinal implant users. PLoS One 2021; 16:e0229189. [PMID: 33566851 PMCID: PMC7875418 DOI: 10.1371/journal.pone.0229189] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 11/30/2020] [Indexed: 01/13/2023] Open
Abstract
INTRODUCTION Retinal implants have now been approved and commercially available for certain clinical populations for over 5 years, with hundreds of individuals implanted, scores of them closely followed in research trials. Despite these numbers, however, few data are available that would help us answer basic questions regarding the nature and outcomes of artificial vision: what do recipients see when the device is turned on for the first time, and how does that change over time? METHODS Semi-structured interviews and observations were undertaken at two sites in France and the UK with 16 recipients who had received either the Argus II or IRIS II devices. Data were collected at various time points in the process that implant recipients went through in receiving and learning to use the device, including initial evaluation, implantation, initial activation and systems fitting, re-education and finally post-education. These data were supplemented with data from interviews conducted with vision rehabilitation specialists at the clinical sites and clinical researchers at the device manufacturers (Second Sight and Pixium Vision). Observational and interview data were transcribed, coded and analyzed using an approach guided by Interpretative Phenomenological Analysis (IPA). RESULTS Implant recipients described the perceptual experience produced by their epiretinal implants as fundamentally, qualitatively different than natural vision. All used terms that invoked electrical stimuli to describe the appearance of their percepts, yet the characteristics used to describe the percepts varied significantly between recipients. Artificial vision for these recipients was a highly specific, learned skill-set that combined particular bodily techniques, associative learning and deductive reasoning in order to build a "lexicon of flashes"-a distinct perceptual vocabulary that they then used to decompose, recompose and interpret their surroundings. The percept did not transform over time; rather, the recipient became better at interpreting the signals they received, using cognitive techniques. The process of using the device never ceased to be cognitively fatiguing, and did not come without risk or cost to the recipient. In exchange, recipients received hope and purpose through participation, as well as a new kind of sensory signal that may not have afforded practical or functional use in daily life but, for some, provided a kind of "contemplative perception" that recipients tailored to individualized activities. CONCLUSION Attending to the qualitative reports of implant recipients regarding the experience of artificial vision provides valuable information not captured by extant clinical outcome measures.
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Abstract
Visual prostheses aim to restore, at least to some extent, vision that leads to the type of perception available for sighted patients. Their effectiveness is almost always evaluated using clinical tests of vision. Clinical vision tests are designed to measure the limits of parameters of a functioning visual system. I argue here that these tests are rarely suited to determine the ability of prosthetic devices and other therapies to restore vision. This paper describes and explains many limitations of these evaluations. Prosthetic vision testing often makes use of multiple-alternative forced-choice (MAFC) procedures. Although these paradigms are suitable for many studies, they are frequently problematic in vision restoration evaluation. Two main types of problems are identified: (1) where nuisance variables provide spurious cues that can be learned in repeated training, which is common in prosthetic vision, and thus defeat the purpose of the test; and (2) even though a test is properly designed and performed, it may not actually measure what the researchers believe, and thus the interpretation of results is wrong. Examples for both types of problems are presented. Additional problems arise from confounding factors in the administration of tests are pointed as limitations of current device evaluation. For example, head tracing of magnified objects enlarged to compensate for the system's low resolution, in distinction from the scanning head (camera) movements with which users of prosthetic devices expand the limited field of view. Because of these problems, the ability to perform satisfactorily on the clinical tests is necessary but insufficient to prove vision restoration, therefore, additional tests are needed. I propose some directions to pursue in such testing. Translational Relevance Numerous prosthetic devices are being developed and introduced to the market. Proving the utility of these devices is crucial for regulatory and even for post market acceptance, which so far has largely failed, in my opinion. Potential reasons for the failures despite success in regulatory testing and directions for designing improved testing are provided. It is hoped that improved testing will guide improved designs of future prosthetic systems and other vision restoration approaches.
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Affiliation(s)
- Eli Peli
- Schepens Eye Research Institute of Mass Eye & Ear, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
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Kvansakul J, Hamilton L, Ayton LN, McCarthy C, Petoe MA. Sensory augmentation to aid training with retinal prostheses. J Neural Eng 2020; 17:045001. [PMID: 32554868 DOI: 10.1088/1741-2552/ab9e1d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
OBJECTIVE Retinal prosthesis recipients require rehabilitative training to learn the non-intuitive nature of prosthetic 'phosphene vision'. This study investigated whether the addition of auditory cues, using The vOICe sensory substitution device (SSD), could improve functional performance with simulated phosphene vision. APPROACH Forty normally sighted subjects completed two visual tasks under three conditions. The phosphene condition converted the image to simulated phosphenes displayed on a virtual reality headset. The SSD condition provided auditory information via stereo headphones, translating the image into sound. Horizontal information was encoded as stereo timing differences between ears, vertical information as pitch, and pixel intensity as audio intensity. The third condition combined phosphenes and SSD. Tasks comprised light localisation from the Basic Assessment of Light and Motion (BaLM) and the Tumbling-E from the Freiburg Acuity and Contrast Test (FrACT). To examine learning effects, twenty of the forty subjects received SSD training prior to assessment. MAIN RESULTS Combining phosphenes with auditory SSD provided better light localisation accuracy than either phosphenes or SSD alone, suggesting a compound benefit of integrating modalities. Although response times for SSD-only were significantly longer than all other conditions, combined condition response times were as fast as phosphene-only, highlighting that audio-visual integration provided both response time and accuracy benefits. Prior SSD training provided a benefit to localisation accuracy and speed in SSD-only (as expected) and Combined conditions compared to untrained SSD-only. Integration of the two modalities did not improve spatial resolution task performance, with resolution limited to that of the higher resolution modality (SSD). SIGNIFICANCE Combining phosphene (visual) and SSD (auditory) modalities was effective even without SSD training and led to an improvement in light localisation accuracy and response times. Spatial resolution performance was dominated by auditory SSD. The results suggest there may be a benefit to including auditory cues when training vision prosthesis recipients.
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Affiliation(s)
- Jessica Kvansakul
- Bionics Institute, East Melbourne, VIC, Australia. Department of Medical Bionics, University of Melbourne, Parkville, VIC, Australia
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