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
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.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
TREATMENT
Masking
NONE
Enrollment
30
epiretinal implantation of device
Doheny Eye Institute
Los Angeles, California, United States
University of California San Francisco
San Francisco, California, United States
Johns Hopkins, Wilmer Eye Institute
Visual Acuity
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.
Time frame: 10 years
Number of Participants With Adverse Events
Evaluate ocular adverse events reported for all subjects from day of implant through 10 years of study participation
Time frame: 10 years
Massof Activity Inventory
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).
Time frame: 3 years
Quality of Life - Tasks for Daily Living
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.
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Baltimore, Maryland, United States
Columbia University, Department of Ophthalmology, Edward S. Harkness Eye Institute
New York, New York, United States
University of Pennsylvania, Scheie Eye Institute
Philadelphia, Pennsylvania, United States
Wills Eye Hospital
Philadelphia, Pennsylvania, United States
Retina Foundation of the Southwest
Dallas, Texas, United States
Centre d'Investigation Clinique, Service d'Ophtalmologie, Quinze-Vingts National Eye Hospital, 28 rue de Charenton, 75557 Cedex 12
Paris, France
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
...and 2 more locations
Time frame: 3 years
Orientation and Mobility
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.
Time frame: 5 years
Visual Function
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.
Time frame: 10 years
Stability of Implant - 5 Years Post Implant
Stability of electrode array on the retina. Qualitative review of imaging: retinal and array landmarks compared from all time points post implant.
Time frame: 5 years
Device Reliability
Number of participants with functional devices 10 years post implant
Time frame: 10 years