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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|
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