The Argus-II Retinal Prosthesis Implantation; From the Global to Local Successful Experience

Farvardin, Mohsen; Afarid, Mehrdad; Attarzadeh, Adel; Johari, Mohammadkarim; Mehryar, M; Nowroozzadeh, Mohammad Hossein; Rahat, Feisal; Peyvandi, Hossein; Farvardin, Reza; Nami, Mohammad

doi:10.3389/fnins.2018.00584

Cited by 34 publications

(32 citation statements)

References 30 publications

(83 reference statements)

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“…The Argus II device is programmed at M1 for initial programming prior to turning on the camera in order to find stimulation levels that are suitable for the patient to be set on their Video Processing Unit (VPU) [ 4 , 5 ]. During the first session, the electrodes whose resistances are too high are disabled and the electrodes that are functional and usable are determined.…”

Section: Methodsmentioning

confidence: 99%

“…A quick scan of the array is done using various stimulation amplitudes to determine which electrodes are able to produce a percept or phosphene. The minimum current that is needed for the patient to see a phosphene 50 % of the time is defined for each electrode [ 1 , 4 ]. The video signal from the camera is mapped to the electrical signal for individual or groups of electrodes, determining which electrodes are being stimulated and at what respective frequency.…”

Section: Methodsmentioning

confidence: 99%

“…These values are set to the patients VPU to be used in different conditions [ 1 ]. Programming for this study included use of the “Programming Assistant” software that is designed to streamline the programming process to measure general sensitivity [ 1 , 4 ]. Through use of this software, the camera alignment process is simplified and comfort is determined under more real-world stimulation conditions [ 1 ].…”

Section: Methodsmentioning

confidence: 99%

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Effect of the electrode array-retina gap distance on visual function in patients with the Argus II retinal prosthesis

et al. 2020

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Background Post-implantation visual outcomes in patients with the Argus II Retinal Prosthesis is dependent on a multitude of factors including the positioning of the electrode array on the retina. The purpose of this study is to determine whether the average electrode array-retina gap distance correlates with objective visual function outcomes and sensitivity detection thresholds in patients implanted with the Argus II Retinal Prosthesis. Methods Five patients with implantation of the Argus II Retinal Prosthesis were enrolled in this single-institution retrospective study. Patient demographics were collected from medical records. Visual function data (Square Localization [SL] and Direction of Motion [DOM]) and Optical Coherence Tomography (Cirrus HD-OCT) images were extracted retrospectively from the Argus II Retinal Prosthesis Post-Approval study. Visual function tests were performed with the device OFF and ON at each study visit. Electrode array-retina gap distances were measured at each of the array’s 60 electrodes using the Cirrus HD-OCT software in both the nasotemporal and superoinferior planes. Data was obtained at baseline, and post-operative month 1, month 3, month 6, and year 1. Sensitivity detection thresholds were obtained at the initial programming visit and each reprogramming session. Results Three patients performed significantly better in SL visual function testing with the device ON. Patients that worsened in visual function testing with the device ON in both SL and DOM testing had a statistically significant decrease in performance. The electrode array-retina gap distance was found to effect performance in SL testing in a patient-dependent manner. No effect was found between the electrode-array gap distance and DOM testing or sensitivity detection threshold. Conclusion Our results demonstrate that the electrode array-retina gap distance may affect visual function outcomes in SL testing in certain patients with the Argus II Retinal Prosthesis, and the direction and magnitude of this effect is likely patient-dependent. Furthermore, complete apposition between the electrode array and retina may not always be necessary to achieve optimal visual outcomes.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Effect of the electrode array-retina gap distance on visual function in patients with the Argus II retinal prosthesis

et al. 2020

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show abstract

“…A quick scan of the array is done using various stimulation amplitudes to determine which electrodes are able to produce a percept or phosphene. The minimum current that is needed for the patient to see a phosphene fty percent of the time is de ned for each electrode 1,4 . The video signal from the camera is mapped to the electrical signal for individual or groups of electrodes, determining which electrodes are being stimulated and at what respective frequency.…”

Section: Sensitivity Detection Thresholdmentioning

confidence: 99%

“…These values are set to the patients VPU to be used in different conditions 1 . Programming for this study included use of the "Programming Assistant" software that is designed to streamline the programming process to measure general sensitivity 1,4 . Through use of this software, the camera alignment process is simpli ed and comfort is determined under more real-world stimulation conditions 1 .…”

Section: Sensitivity Detection Thresholdmentioning

confidence: 99%

Effect of the Electrode Array-Retina Gap Distance on Visual Function in Patients with the Argus II Retinal Prosthesis

Naidu

Ghani

Yazdanie

et al. 2020

Preprint

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Background: Post-implantation visual outcomes in patients with the Argus II Retinal Prosthesis is dependent on a multitude of factors including the positioning of the electrode array on the retina. The purpose of this study is to determine whether the average electrode array-retina gap distance correlates with objective visual function outcomes and sensitivity detection thresholds in patients implanted with the Argus II Retinal Prosthesis.Methods: 5 patients with implantation of the Argus II Retinal Prosthesis were enrolled in this single-institution retrospective study. Patient demographics were collected from medical records. Visual function data (Square Localization [SL] and Direction of Motion [DOM]) and Optical Coherence Tomography (Cirrus HD-OCT) images were extracted retrospectively from the Argus II Retinal Prosthesis Post-Approval study. Visual function tests were performed with the device OFF and ON at each study visit. Electrode array-retina gap distances were measured at each of the array’s 60 electrodes using the Cirrus HD-OCT software in both the nasotemporal and superoinferior planes. Data was obtained at baseline, and post-operative month 1, month 3, month 6, and year 1. Sensitivity detection thresholds were obtained at the initial programming visit and each reprogramming session. Results: 3 patients performed significantly better in SL visual function testing with the device ON. Patients that worsened in visual function testing with the device ON in both SL and DOM testing had a statistically significant decrease in performance. The electrode array-retina gap distance was found to effect performance in SL testing in a patient-dependent manner. No effect was found between the electrode-array gap distance and DOM testing or sensitivity detection threshold. Conclusion: Our results demonstrate that the electrode array-retina gap distance may affect visual function outcomes in SL testing in certain patients with the Argus II Retinal Prosthesis, and the direction and magnitude of this effect is likely patient-dependent. Furthermore, complete apposition between the electrode array and retina may not always be necessary to achieve optimal visual outcomes.

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Recent Advances in Encapsulation of Flexible Bioelectronic Implants: Materials, Technologies, and Characterization Methods

Mariello

Kim

et al. 2022

Advanced Materials

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Bioelectronic implantable systems (BIS) targeting biomedical and clinical research should combine long‐term performance and biointegration in vivo. Here, recent advances in novel encapsulations to protect flexible versions of such systems from the surrounding biological environment are reviewed, focusing on material strategies and synthesis techniques. Considerable effort is put on thin‐film encapsulation (TFE), and specifically organic–inorganic multilayer architectures as a flexible and conformal alternative to conventional rigid cans. TFE is in direct contact with the biological medium and thus must exhibit not only biocompatibility, inertness, and hermeticity but also mechanical robustness, conformability, and compatibility with the manufacturing of microfabricated devices. Quantitative characterization methods of the barrier and mechanical performance of the TFE are reviewed with a particular emphasis on water‐vapor transmission rate through electrical, optical, or electrochemical principles. The integrability and functionalization of TFE into functional bioelectronic interfaces are also discussed. TFE represents a must‐have component for the next‐generation bioelectronic implants with diagnostic or therapeutic functions in human healthcare and precision medicine.

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The Argus-II Retinal Prosthesis Implantation; From the Global to Local Successful Experience

Cited by 34 publications

References 30 publications

Effect of the electrode array-retina gap distance on visual function in patients with the Argus II retinal prosthesis

Effect of the electrode array-retina gap distance on visual function in patients with the Argus II retinal prosthesis

Effect of the Electrode Array-Retina Gap Distance on Visual Function in Patients with the Argus II Retinal Prosthesis

Recent Advances in Encapsulation of Flexible Bioelectronic Implants: Materials, Technologies, and Characterization Methods

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