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Experimental and Clinical Studies of Retinal Stimulation

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details. Identifier: NCT03635645
Recruitment Status : Recruiting
First Posted : August 17, 2018
Last Update Posted : August 17, 2018
National Eye Institute (NEI)
Information provided by (Responsible Party):
James Weiland, University of Michigan

Brief Summary:
The study will evaluate new methods of retinal stimulation and training with the goal of improving the visual ability of retinal prosthesis participants.

Condition or disease Intervention/treatment Phase
Retinitis Pigmentosa Device: New visual processing unit (VPU) with asymmetric waveforms Device: New VPU with bipolar stimulation Not Applicable

Detailed Description:
The study will test new ways to make the retinal prosthesis visual perception easier with auditory-visual training and how to make the retinal prosthesis work better at perceiving shapes.

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 10 participants
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Other
Official Title: Experimental and Clinical Studies of Retinal Stimulation
Actual Study Start Date : October 30, 2017
Estimated Primary Completion Date : October 2020
Estimated Study Completion Date : October 2020

Resource links provided by the National Library of Medicine

Arm Intervention/treatment
Experimental: Retinal stimulation
Alternative stimulus patterns will be tested (vs. baseline). The intervention is the alternative stimulus pattern. The intervention will be tested only in the clinic vs. baseline. The subject will go home with baseline settings. The two alternative stimulus patterns to be tested are asymmetric waveforms and bipolar stimulus.
Device: New visual processing unit (VPU) with asymmetric waveforms
A VPU will apply asymmetric and symmetric stimulation pulses.

Device: New VPU with bipolar stimulation
A VPU will apply bipolar stimulus pulses.

Primary Outcome Measures :
  1. Percent change in stimulus thresholds [ Time Frame: Baseline, 8 hours ]
    Compare baseline threshold with threshold of modified stimulus parameters. Threshold is measured in microCoulumbs ( the product of stimulus duration and stimulus amplitude).

  2. Change in shape perception [ Time Frame: Baseline, 8 hours ]
    As measured by elongation ratio. The elongation ratio is the ratio of major axis length to minor axis length of an ellipse. Subjects will draw shapes on a touch screen and these shapes will be fit to an ellipse.

Information from the National Library of Medicine

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Ages Eligible for Study:   25 Years to 89 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Must be implanted with an Argus II Retinal Prosthesis system.
  • Have 5 or more electrodes that create a perception with stimulation.
  • Must be willing and able to comply with the protocol testing requirements.

Exclusion Criteria:

  • Subjects participating in another investigatory drug or device study
  • Any disease or condition that prevents understanding or communication of informed consent, study demands, and testing protocols.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT03635645

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Contact: James Weiland 661-713-4603

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United States, Michigan
University of Michigan Recruiting
Ann Arbor, Michigan, United States, 48105
Contact: James Weiland    661-713-4603   
Sponsors and Collaborators
University of Michigan
National Eye Institute (NEI)
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Principal Investigator: James Weiland University of Michigan

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Responsible Party: James Weiland, Professor of Biomedical Engineering, University of Michigan Identifier: NCT03635645     History of Changes
Other Study ID Numbers: HUM00122699
R01EY022931-05 ( U.S. NIH Grant/Contract )
First Posted: August 17, 2018    Key Record Dates
Last Update Posted: August 17, 2018
Last Verified: August 2018

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: Yes
Device Product Not Approved or Cleared by U.S. FDA: Yes
Pediatric Postmarket Surveillance of a Device Product: No

Additional relevant MeSH terms:
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Retinitis Pigmentosa
Retinal Diseases
Eye Diseases
Eye Diseases, Hereditary
Retinal Dystrophies
Retinal Degeneration
Genetic Diseases, Inborn