A Second-Generation (44-Channel) Suprachoroidal Retinal Prosthesis: Long-Term Observation of the Electrode–Tissue Interface

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dc.contributor.authorTitchener, Samuel
dc.contributor.authorNayagam, David
dc.contributor.authorKvansakul, Jessica
dc.contributor.authorKolic, Maria
dc.contributor.authorBaglin, Elizabeth
dc.contributor.authorAbbott, Carla
dc.contributor.authorMcGuinness, Myra
dc.contributor.authorAyton, Lauren
dc.contributor.authorLuu, Chi
dc.contributor.authorGreenstein, Steven
dc.contributor.authorKentler, William
dc.contributor.authorShivdasani, Mohit
dc.contributor.authorAllen, Penelope
dc.contributor.authorPetoe, Matthew
dc.date.accessioned2022-08-02T03:45:21Z
dc.date.available2022-08-02T03:45:21Z
dc.date.issued2022-06
dc.description.abstractPurpose: To report the long-term observations of the electrode–tissue interface and perceptual stability in humans after chronic stimulation with a 44-channel suprachoroidal retinal implant. Methods: Four subjects (S1–4) with end-stage retinitis pigmentosa received the implant unilaterally (NCT03406416). Electrode impedances, electrode–retina distance (measured using optical coherence tomography imaging), and perceptual thresholds were monitored up to 181 weeks after implantation as the subjects used the prosthesis in the laboratory and in daily life. Stimulation charge density was limited to 32 µC/cm2 per phase. Results: Electrode impedances were stable longitudinally. The electrode–retina distances increased after surgery and then stabilized, and were well-described by an asymptotic exponential model. The stabilization of electrode–retina distances was variable between subjects, stabilizing after 45 weeks for S1, 63 weeks for S2, and 24 weeks for S3 (linear regression; Pgradient > 0.05). For S4, a statistically significant increase in electrode–retina distance persisted (P < 0.05), but by the study end point the rate of increase was clinically insignificant (exponential model: 0.33 µm/wk). Perceptual electrical thresholds were stable in one subject, decreased over time in two subjects (linear model; P < 0.05), and increased slightly in one subject but remained within the predefined charge limits (P = 0.02). Conclusions: Chronic stimulation with the suprachoroidal retinal prosthesis over 3 years resulted in stable impedances, small individual changes in perceptual electrical thresholds, and no clinically significant increase in electrode–retina distances after a period of settling after surgery. Translational Relevance: Chronic stimulation with the 44-channel suprachoroidal retinal implant with a charge density of up to 32 µC/cm2 per phase is suitable for long-term use in humans.en_US
dc.description.sponsorshipSupported by the National Health and Medical Research Council (NHMRC) Grant 1082358 (P.J.A., M.P., L.A.; Canberra, ACT, Australia) and Bionic Vision Technologies Pty Ltd (Australia). The Bionics Institute and the Centre for Eye Research Australia wish to acknowledge the support of the Victorian Government through its Operational Infrastructure Support Program (Victoria, Australia), and the generous support of the estate of the late Brian Entwisle.en_US
dc.identifier.citationTitchener SA, Nayagam DAX, Kvansakul J, Kolic M, Baglin EK, Abbott CJ, McGuinness MB, Ayton LN, Luu CD, Greenstein S, Kentler WG, Shivdasani MN, Allen PJ, Petoe MA. A Second-Generation (44-Channel) Suprachoroidal Retinal Prosthesis: Long-Term Observation of the Electrode–Tissue Interface. Trans Vis Sci Tech. 2022;11(6):12en_US
dc.identifier.issn2164-2591
dc.identifier.urihttp://repository.bionicsinstitute.org:8080/handle/123456789/420
dc.language.isoenen_US
dc.publisherTranslational Vision Science & Technologyen_US
dc.subjectVisual prosthesisen_US
dc.subjectRetinal prosthesisen_US
dc.titleA Second-Generation (44-Channel) Suprachoroidal Retinal Prosthesis: Long-Term Observation of the Electrode–Tissue Interfaceen_US
dc.typeArticleen_US
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