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Ophthalmology. 2018 Mar;125(3):432-443. doi: 10.1016/j.ophtha.2017.09.019. Epub 2017 Oct 27.

Assessment of the Electronic Retinal Implant Alpha AMS in Restoring Vision to Blind Patients with End-Stage Retinitis Pigmentosa.

Author information

1
Nuffield Laboratory of Ophthalmology, University of Oxford, United Kingdom; Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom. Electronic address: thomas.edwards@ndcn.ox.ac.uk.
2
Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom.
3
Nuffield Laboratory of Ophthalmology, University of Oxford, United Kingdom; Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, United Kingdom.
4
Nuffield Laboratory of Ophthalmology, University of Oxford, United Kingdom.
5
Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany; Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany.

Abstract

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.

PMID:
29110946
PMCID:
PMC5818267
DOI:
10.1016/j.ophtha.2017.09.019
[Indexed for MEDLINE]
Free PMC Article

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