Argus® II Retinal Stimulation System Feasibility Protocol
- Conditions
- Retinitis Pigmentosa
- Interventions
- Device: Implant of Argus II Retinal Prosthesis
- Registration Number
- NCT00407602
- Lead Sponsor
- Second Sight Medical Products
- Brief Summary
Investigational Phase of the Study:
The objective of this feasibility study is to evaluate the safety and utility of the Argus II Retinal Stimulation System in providing visual function to blind subjects with retinitis pigmentosa.
Post-Approval Phase of the Study:
To collect post-approval data in order to monitor the ongoing safety and reliability of the Argus II System
- Detailed Description
During the post-approval phase, subjects will undergo annual eye exams, assessments of medical status and adverse events, and measurement of stimulation thresholds. In addition, at the mutual agreement of the investigator and the subject, subjects will have the option of participating in psychophysical research which could occur as frequently as monthly. Functional tests at 10 years: photographic flash, square localization, direction of motion and grating visual acuity.
Recruitment & Eligibility
- Status
- COMPLETED
- Sex
- All
- Target Recruitment
- 30
- A confirmed history of retinitis pigmentosa (all centers) or outer retinal degeneration (France, U.K., Switzerland, Mexico only) with remaining visual acuity of bare light perception (all centers) or 2.3 logMAR (France, U.K., Switzerland, Mexico only) or worse in both eyes.
- Functional ganglion cells and optic nerve as determined by a measurable electrically evoked response or documented light perception.
- A history of former useful form vision in the worse-seeing eye.
- Must be at least the following age at the time of enrollment: 25 (USA, Switzerland) or 18 (France, U.K., and Mexico) years old
- Must reside within 2 hours (USA, UK and Mexico) or 3 hours (France and Switzerland) distance (by ground transportation) of the investigational site.
- Must be willing and able to comply with the protocol testing and follow-up requirements.
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Optic Nerve disease
- History of glaucoma
- Optic neuropathy or other confirmed damage to optic nerve or visual cortex damage
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Diseases or conditions that effect retinal function including but not limited to:
- Central retinal artery/vein occlusion (CRAO or CRVO)
- End-stage diabetic retinopathy
- Retinal detachment or history of retinal detachment
- Trauma
- Infectious or inflammatory retinal diseases
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Diseases or conditions that prevent adequate visualization of the retina including, but not limited to corneal degeneration that cannot be resolved before implant.
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Diseases or conditions of the anterior segment that prevent the ability to adequately perform the physical examination including but not limited to trauma or lid malpositions.
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Diseases of the ocular surface including but not limited to keratitis sicca.
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An ocular condition that predisposes the subject to eye rubbing.
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Any disease or condition that prevents understanding or communication of informed consent, study demands, and testing protocols, including:
- Cognitive decline including diagnosed forms of dementia and/or progressive neurological disease
- Psychiatric Disease including diagnosed forms of depression
- Does not speak a principal language associated with the region
- Deafness or selective frequency hearing loss that prevents hearing device alarms and alerts.
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Pregnancy
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Subject has another active implantable device (e.g. cochlear implant), or any form of metallic implant in the head
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Conjunctival thinning which may predispose the subject to conjunctival erosion in the area where the implant will be installed extra-ocularly.
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Subject is participating in another investigational drug or device study that may conflict with the objectives, follow-up or testing of this study
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Any health concern that makes general anesthesia inadvisable.
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Subject has unrealistic expectations of the implant.
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Known allergy or contraindication to anticipated pre-operative, intra-operative or post-operative medications.
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Conditions likely to limit life to less than 1 year from the time of screening.
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Diseases or conditions that, in the judgement of the surgeon, impede the ability to implant the device or would prevent the system from functioning for the duration of the study (e.g. strabismus)
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Axial eye length <21.5 mm or >26.0 mm in the implanted eye as measured by ultrasound (US only)
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- SINGLE_GROUP
- Arm && Interventions
Group Intervention Description Implant of Argus II Retinal Prosthesis Implant of Argus II Retinal Prosthesis This is a single group study where the status and performance of the implanted eye prior to surgery serves as the comparator.
- Primary Outcome Measures
Name Time Method Visual Acuity 10 years Grating Visual Acuity is performed at Baseline and at various timepoints throughout the study. As of the 10 year final testing, the total number of subjects that were able to score on the logMAR scale are indicated below. The device has a scale from 1.6 to 2.9 logMAR. Maximum likelihood estimation of visual acuity is based on BEST-PEST algorithm.
Number of Participants With Adverse Events 10 years Evaluate ocular adverse events reported for all subjects from day of implant through 10 years of study participation
- Secondary Outcome Measures
Name Time Method Visual Function 10 years Square localization (SL) and Direction of Motion (DOM) testing performed at specific protocol intervals. SL tests ability of subjects to locate high-contrast square on black screen. DOM tests ability of subjects to determine the direction a white bar is moving over a black screen. Each test is performed with the system ON and then compared to performance with the system OFF. Number of subjects who performed significantly better with the system ON is indicated below.
Quality of Life - Tasks for Daily Living 3 years Quality of life is being measured using the VisQOL survey. This instrument, developed by researchers at the University of Melbourne, Australia, is a vision and quality of life-related utility measure intended to evaluate healthcare interventions for the visually impaired. The utility score is a preference-based measure of vision-related quality of life (Dimension 7 score (Health Dimension Score (1=Best, 0=Worst)). It measures subjective quality of life on a scale of 0 to 1, where 0 represents worst possible quality of life and 1 represents perfect quality of life.
Orientation and Mobility 5 years Argus II System for orientation and mobility, each subject completed two tests (walking to a high-contrast "door" on the wall and following a straight line on the floor) at various timepoints throughout the study. Accuracy (percent of trials where the subject successfully reached the target) was measured with the device system ON and system OFF. Average % success rates across the analysis population are provided for each modality and for each test at the 60 month time point.
Stability of Implant - 5 Years Post Implant 5 years Stability of electrode array on the retina. Qualitative review of imaging: retinal and array landmarks compared from all time points post implant.
Massof Activity Inventory 3 years The Massof Activity Inventory measures changes in ability to perform activities of daily living in terms of Goals and Tasks in logits (log-odds units). A logit scale is an equal interval linear scale that represents probability values in terms of real numbers. There is no minimum or maximum scale used in this testing. In this case, a Rasch distribution (using an Andrich rating model) was used to find the maximum likelihood of difficulty of achieving Goals and Tasks, represented in logits. The change in mean logit value between baseline and the 36Month visit for each subject are provided below along with the 95% confidence interval (CI) for the change. A positive change in the Goals or Tasks score which is greater than 0.2 (with a CI less than the mean logit value), is interpreted as a clinically significant increase in functional ability (better outcome).
Device Reliability 10 years Number of participants with functional devices 10 years post implant
Trial Locations
- Locations (12)
University of Pennsylvania, Scheie Eye Institute
🇺🇸Philadelphia, Pennsylvania, United States
Moorfields Eye Hospital, Vitreoretinal Research Unit
🇬🇧London, United Kingdom
Manchester Royal Eye Hospital
🇬🇧Manchester, United Kingdom
University of California San Francisco
🇺🇸San Francisco, California, United States
Centre d'Investigation Clinique, Service d'Ophtalmologie, Quinze-Vingts National Eye Hospital, 28 rue de Charenton, 75557 Cedex 12
🇫🇷Paris, France
Wills Eye Hospital
🇺🇸Philadelphia, Pennsylvania, United States
Columbia University, Department of Ophthalmology, Edward S. Harkness Eye Institute
🇺🇸New York, New York, United States
Doheny Eye Institute
🇺🇸Los Angeles, California, United States
Johns Hopkins, Wilmer Eye Institute
🇺🇸Baltimore, Maryland, United States
Retina Foundation of the Southwest
🇺🇸Dallas, Texas, United States
Puerta de Hierro, Centro Medico, Centro de Retina
🇲🇽Zapopan, Jalisco, Mexico
Clinique d'Ophthalmologie Hopitaux, Universitaires de Geneve 22 rue Alcide Jentzer 1205
🇨🇭Geneva, Switzerland