Long-term observations of macular thickness after subretinal implantation of a photovoltaic prosthesis in patients with atrophic age-related macular degeneration

Mahiul M K Muqit7,1,2Yannick Le Mer3Frank G Holz4 and José A Sahel3,5,6

Published 14 October 2022 • © 2022 IOP Publishing Ltd
Journal of Neural EngineeringVolume 19Number 5

Citation Mahiul M K Muqit et al 2022 J. Neural Eng. 19 055011DOI 10.1088/1741-2552/ac9645

 

Abstract

Objective. Subretinal prostheses electrically stimulate the residual inner retinal neurons to partially restore vision. We investigated the changes in neurosensory macular structures and it is thickness associated with subretinal implantation in geographic atrophy (GA) secondary to age-related macular degeneration (AMD). Approach. Using optical coherence tomography, changes in distance between electrodes and retinal inner nuclear layer (INL) as well as alterations in thickness of retinal layers were measured over time above and near the subretinal chip implanted within the atrophic area. Retinal thickness (RT) was quantified across the implant surface and edges as well as outside the implant zone to compare with the natural macular changes following subretinal surgery, and the natural course of dry AMD. Main results. GA was defined based on complete retinal pigment epithelium and outer retinal atrophy (cRORA). Based on the analysis of three patients with subretinal implantation, we found that the distance between the implant and the target cells was stable over the long-term follow-up. Total RT above the implant decreased on average, by 39 ± 12 µm during 3 months post-implantation, but no significant changes were observed after that, up to 36 months of the follow-up. RT also changed near the temporal entry point areas outside the implantation zone following the surgical trauma of retinal detachment. There was no change in the macula cRORA nasal to the implanted zone, where there was no surgical trauma or manipulation. Significance. The surgical delivery of the photovoltaic subretinal implant causes minor RT changes that settle after 3 months, and then remain stable over long-term with no adverse structural or functional effects. Distance between the implant and the INL remains stable up to 36 months of the follow-up.

 

2022-11-28T15:29:15+01:00October 14th, 2022|Publications|

Simultaneous perception of prosthetic and natural vision in AMD patients

Abstract
Loss of photoreceptors in atrophic age-related macular degeneration (AMD) results in severe visual impairment. Since the low-resolution peripheral vision is retained in such conditions, restoration of central vision should not jeopardize the surrounding healthy retina and allow for simultaneous use of the natural and prosthetic sight. This interim report, prespecified in the study protocol, presents the first clinical results with a photovoltaic substitute of the photoreceptors providing simultaneous use of the central prosthetic and peripheral natural vision in atrophic AMD. In this open-label single group feasibility trial (NCT03333954, recruitment completed), five patients with geographic atrophy have been implanted with a wireless 2 x 2 mm-wide 30 µm-thick device, having 378 pixels of 100 µm in size. All 5 patients achieved the primary outcome of the study by demonstrating the prosthetic visual perception in the former scotoma. The four patients with a subretinal placement of the chip demonstrated the secondary outcome: Landolt acuity of 1.17 ± 0.13 pixels, corresponding to the Snellen range of 20/460–20/565. With electronic magnification of up to a factor of 8, patients demonstrated prosthetic acuity in the range of 20/63–20/98. Under room lighting conditions, patients could simultaneously use prosthetic central vision and their remaining peripheral vision in the implanted eye and in the fellow eye.

2022-11-28T15:17:34+01:00January 27th, 2022|Publications|

Photovoltaic Restoration of Central Vision in Atrophic Age-Related Macular Degeneration

Implantation of the PRIMA did not decrease the residual natural acuity, and it restored visual sensitivity in the former scotoma in each of the 5 patients. In 3 patients with the proper placement of the chip, prosthetic visual acuity was only 10% to 30% less than the level expected from the pixel pitch (20/420).
Therefore, the use of optical or electronic magnification in the glasses as well as smaller pixels in future implants may improve visual acuity even further

2020-07-21T11:55:51+02:00July 21st, 2020|Publications|

Restoration of sight in geographic atrophy using a photovoltaic subretinal prosthesis

OBJECTIVE: To
evaluate feasibility of restoration of central vision in patients with
age-related macular degeneration using a wireless photovoltaic subretinal
implant. In particular, to assess safety of sub-retinal implantation and
quality of prosthetic vision in patients with geographic atrophy.
CONCLUSIONS:
Wireless
chip PRIMA can be safely implanted under the atrophic macula in patients with
geographic atrophy and restore central visual perception with acuity close to
the theoretical limit of the implant. Implantation did not reduce the natural
residual visual acuity of the patients. Implants with smaller pixels are being
developed.

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2019-09-11T17:29:56+02:00June 28th, 2019|Publications|

Optimization of pillar electrodes in subretinal prosthesis for enhanced proximity to target neurons


According to computational model, pillars having a cathodic return electrode above the INL and active anodic ring electrode at the surface of the implant would enable lower stimulation threshold, compared to planar arrays with circumferential return, but suffer from greater cross-talk between the neighboring pixels. Significance. 3D electrodes in subretinal prostheses help reduce electrode-tissue separation and decrease stimulation thresholds to enable smaller pixels, and thereby improve visual acuity of prosthetic vision.Thomas Flores, Xin Lei, Tiffany Huang, Henri Lorach, Roopa Dalal, Ludwig Galambos, Theodore Kamins, Keith Mathieson and Daniel PalankerPublished 5 March 2018 • © 2018 IOP Publishing Ltd Journal of Neural Engineering, Volume 15, Number 3

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2019-09-11T17:31:50+02:00March 5th, 2018|Publications|

Deafferented adult rod bipolar cells create new synapses with photoreceptors to restore vision

Loss of photoreceptors during retinal degeneration results in permanent visual impairment. Strategies for vision restoration based on the reintroduction of photoreceptors inherently rely on the ability of the remaining retinal neurons to correctly synapse with new photoreceptors. We show that deafferented bipolar cells in the adult mammalian retina can reconnect to rods and cones and restore retinal sensitivity at scotopic and photopic luminances.

Corinne Beier, Anahit Hovhannisyan, Sydney Weiser, Jennifer Kung, Seungjun Lee, Dae Yeong Lee, Philip Huie, Roopa Dalal, Daniel Palanker and Alexander Sher

Journal of Neuroscience 3 April 2017, 2570-16; DOI: https://doi.org/10.1523/JNEUROSCI.2570-16.2017

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2019-09-11T17:32:28+02:00April 7th, 2017|Publications|

ARTIFICIAL VISION : Pixium Vision: First Clinical Results and Innovative Developments


Pixium Vision and its partners are developing two VRS solutions for blind patients: an epi-retinal and a sub-retinal approach. This chapter describes the specificities of the epi-retinal IRIS® VRS that has obtained the European CE mark cerfication, and also discuss the associatedinnovations developed at the Vision Institute for future VRS models.

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2019-09-11T17:32:32+02:00November 25th, 2016|Publications|

ATIS – Event-Based Tone Mapping for Asynchronous Time-Based Image Sensor


The asynchronous time-based neuromorphic image sensor ATIS is an array of autonomously operating pixels able to encode luminance information with an exceptionally high dynamic range (>143 dB). This paper introduces an event-based methodology to display data from this type of event-based imagers, taking into account the large dynamic range and high temporal accuracy that go beyond available mainstream display technologies.

Camille Simon Chane, Sio-Hoi Ieng, Christoph Posch and Ryad B. Benosman
Front. Neurosci., 31 August 2016 | https://doi.org/10.3389/fnins.2016.00391

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2019-09-11T17:32:28+02:00August 31st, 2016|Publications|
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