Assessment of the electronic retinal implant alpha AMS in restoring vision to blind patients with end-stage retinitis pigmentosa
Open accessAbstract
PURPOSE: To report the initial efficacy results of the Retina Implant Alpha AMS (Retina Implant AG, Reutlingen, Germany) for partial restoration of vision in end-stage retinitis pigmentosa (RP). DESIGN: Prospective, single-arm, investigator-sponsored interventional clinical trial. Within-participant control comprising residual vision with the retinal implant switched ON versus OFF in the implanted eye. PARTICIPANTS: The Retina Implant Alpha AMS was implanted into the worse-seeing eye of 6 participants with end-stage RP and no useful perception of light vision. Eligibility criteria included previous normal vision for ≥12 years and no significant ocular or systemic comorbidity. METHODS: Vision assessments were scheduled at 1, 2, 3, 6, 9, and 12 months postimplantation. They comprised tabletop object recognition tasks, a self-assessment mobility questionnaire, and screen-based tests including Basic Light and Motion (BaLM), grating acuity, and greyscale contrast discrimination. A full-field stimulus test (FST) was also performed. MAIN OUTCOME MEASURES: Improvement in activities of daily living, recognition tasks, and assessments of light perception with the implant ON compared with OFF. RESULTS: All 6 participants underwent successful implantation. Light perception and temporal resolution with the implant ON were achieved in all participants. Light localization was achieved with the implant ON in all but 1 participant (P4) in whom the chip was not functioning optimally because of a combination of iatrogenic intraoperative implant damage and incorrect implantation. Implant ON correct grating detections (which were at chance level with implant OFF) were recorded in the other 5 participants, ranging from 0.1 to 3.33 cycles/degree on 1 occasion. The ability to locate high-contrast tabletop objects not seen with the implant OFF was partially restored with the implant ON in all but 1 participant (P4). There were 2 incidents of conjunctival erosion and 1 inferotemporal macula-on retinal detachment, which were successfully repaired, and 2 incidents of inadvertent damage to the implant during surgery (P3 and P4). CONCLUSIONS: The Alpha AMS subretinal implant improved visual performance in 5 of 6 participants and has exhibited ongoing function for up to 24 months. Although implantation surgery remains challenging, new developments such as OCT microscope guidance added refinements to the surgical technique.
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Only one subretinal prosthesis, the Alpha IMS implant and its successor Alpha AMS, have received marketing approval (CE mark).
“Today, only one subretinal prosthesis, the Alpha IMS implant (figure 5(b)) and its successor Alpha AMS (Retina Implant AG), have received marketing approval (CE mark) [52,53].”
From Advances in visual prostheses: engineering and biological challenges (2022) · cites this paper as [53]
So far, retinal prostheses have reached marketing approval, and other devices are in preclinical and clinical testing.
“So far, retinal prostheses have reached marketing approval [23,53,111], and other devices are in preclinical and clinical testing.”
From Advances in visual prostheses: engineering and biological challenges (2022) · cites this paper as [53]
Grating acuities reported in the literature range from 20/1260 with the epiretinal Argus II implant to 20/364 with the subretinal Alpha-AMS implant.
“Grating acuities reported in the literature range from 20/1260 with the epiretinal Argus® II implant to 20/364 with the subretinal Alpha-AMS implant [53].”
From Advances in visual prostheses: engineering and biological challenges (2022) · cites this paper as [53]
The best documented grating acuity with Alpha AMS was about 0.95 logMAR (6/60 Snellen), though it varied significantly over time and between patients.
“The best documented grating visual acuity with Alpha AMS has been equivalent to around 0.95 logMAR (6/60 Snellen), although significant variations exist over time and between patients [Stingl 2017; Edwards 2018].”
From Correcting visual loss by genetics and prosthetics (2020) · cites this paper as Edwards 2018
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“34 Although both devices obtained CE marking, they were never commercialized due to their insufficient technological and clinical performance, and the company was dissolved in 2019.”
- Authors
- Edwards, T. L., Cottriall, C. L., Xue, K., Simunovic, M. P., Ramsden, J. D., Zrenner, E., & MacLaren, R. E.
- Affiliations
- University of Oxford (GB)
- Oxford University Hospitals NHS Trust (GB)
- University of Tübingen (DE)
- Corresponding author
- Edwards, Thomas L.
- Venue
- Ophthalmology
- Publisher
- Elsevier BV
- Published
- 2018-03
- Volume
- 125
- Issue
- 3
- Pages
- 432-443
- ISSN
- 0161-6420 (ISSN-L)
- PMC
- PMC5818267
- OpenAlex
- W2766112309
- Cited by
- 193
- References
- 29
- Citations by year
- 2026: 17 · 2025: 21 · 2024: 22 · 2023: 20 · 2022: 32 · 2021: 27 · 2020: 24 · 2019: 18 · 2018: 11 · 2016: 1
- FWCI
- 7.10
- Type
- journal article
- Language
- en
- Open access
- hybrid
- doi.org
- Locations
- Ophthalmology (publishedVersion, cc-by)
- PubMed Central (publishedVersion, cc-by)
- PubMed (publishedVersion)
- Funders
- National Institute for Health and Care Research (II-C2-0713-20005, CL-2014-13-003)
- University of Oxford
- Eberhard Karls Universität Tübingen (EXC 307)
- Oxford University Hospitals NHS Foundation Trust
- Universität Ulm
- National Institutes of Health
- Invention for Innovation
- Topics
- Life Sciences › Neuroscience › Cellular and Molecular Neuroscience › Neuroscience and Neural Engineering
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Molecular Biology › Retinal Development and Disorders
- Health Sciences › Medicine › Ophthalmology › Retinal Diseases and Treatments
- Keywords
- subretinal implant, retinitis pigmentosa, vision restoration, light perception, grating acuity, contrast discrimination, object recognition, activities of daily living, implant complications, retinal prosthesis
- MeSH terms
- Activities of Daily Living, Electrodes, Implanted, Female, Follow-Up Studies, Humans, Male, Middle Aged, Prospective Studies, Prosthesis Design, Retina, Retinitis Pigmentosa, Visual Acuity, Visual Perception, Single-Blind Method, Treatment Outcome, Tomography, Optical Coherence, Visual Prosthesis
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