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Clinical Trial
, 119 (4), 779-88

Interim Results From the International Trial of Second Sight's Visual Prosthesis

Affiliations
Clinical Trial

Interim Results From the International Trial of Second Sight's Visual Prosthesis

Mark S Humayun et al. Ophthalmology.

Abstract

Purpose: This study evaluated the Argus II Retinal Prosthesis System (Second Sight Medical Products, Inc., Sylmar, CA) in blind subjects with severe outer retinal degeneration.

Design: Single-arm, prospective, multicenter clinical trial.

Participants: Thirty subjects were enrolled in the United States and Europe between June 6, 2007, and August 11, 2009. All subjects were followed up for a minimum of 6 months and up to 2.7 years.

Methods: The electronic stimulator and antenna of the implant were sutured onto the sclera using an encircling silicone band. Next, a pars plana vitrectomy was performed, and the electrode array and cable were introduced into the eye via a pars plana sclerotomy. The microelectrode array then was tacked to the epiretinal surface.

Main outcome measures: The primary safety end points for the trial were the number, severity, and relation of adverse events. Principal performance end points were assessments of visual function as well as performance on orientation and mobility tasks.

Results: Subjects performed statistically better with the system on versus off in the following tasks: object localization (96% of subjects), motion discrimination (57%), and discrimination of oriented gratings (23%). The best recorded visual acuity to date is 20/1260. Subjects' mean performance on orientation and mobility tasks was significantly better when the system was on versus off. Seventy percent of the patients did not have any serious adverse events (SAEs). The most common SAE reported was either conjunctival erosion or dehiscence over the extraocular implant and was treated successfully in all subjects except in one, who required explantation of the device without further complications.

Conclusions: The long-term safety results of Second Sight's retinal prosthesis system are acceptable, and most subjects with profound visual loss perform better on visual tasks with system than without it.

Conflict of interest statement

Conflict of Interest: Authors with financial interests or relationships to disclose are listed after the references.

Conflict of Interest related to the study sponsor, Second Sight Medical Products (SSMP):

Mark S. Humayun has financial interests in SSMP and is employed by an institution that receives funds from SSMP

Jessy D. Dorn and Robert J. Greenberg are employed by and have stock options in SSMP

Aries Arditi has received a consulting fee from SSMP and was employed by an institution that receives funds from SSMP

Artur V. Cideciyan, Lyndon da Cruz, Gislin Dagnelie, Dean Eliott, Eugene Filley, Avinoam B. Safran, and José-Alain Sahel are or were employed by institutions that receive funds from SSMP

Jacque L.Duncan, Lucian V. Del Priore, Allen C. Ho, Arturo Santos, and Paulo E. Stanga have no conflict of interests to disclose

Figures

Figure 1
Figure 1
(A) A photograph of the external portion of the Argus II prosthesis system including glasses-mounted video camera, radio frequency (RF) coil, and Video Processing Unit (VPU) with rechargeable battery. (B) A photograph of the implanted portion of Argus II prosthesis system including the 6×10 electrode array, electronics case, and implant RF coil.
Figure 2
Figure 2
(A) Fundus photograph of implanted Argus II array in the macular region. The electrode array is secured to the retina with a retinal tack; the white square visible on the distal side of the array is an opaque section of tubing (the “handle”) used by the surgeon to position the array. (B) An optical coherence tomography (OCT) image of an implanted Argus II array. Shadows cast on the retinal image (white arrows) are due to occlusion of the scanning light source by the metal electrodes.
Figure 3
Figure 3
Mean accuracy on the Square Localization task for each subject, System ON (filled diamonds) and OFF (open squares). Subjects are ordered along the x-axis from greatest difference between ON and OFF performance to least difference. Error bars indicate standard error. Asterisks indicate subjects for whom the mean System ON performance was significantly different from the mean System OFF performance (t-test assuming unequal variances, two-tailed, p<0.05). Data are the latest available for each subject as of 1 March 2010.
Figure 4
Figure 4
Mean response error for each subject on the Direction of Motion task, System ON (filled diamonds) and system OFF (empty squares). Subjects are ordered along the x-axis from greatest difference between ON and OFF performance to least difference. Single asterisks indicate subjects for whom the System ON mean was significantly different (smaller) than the System OFF mean, and the double asterisk indicates a subject for whom System OFF was significantly different (smaller) than System ON (t-test assuming unequal variances, two-tailed, p<0.05). Data are the latest available for each subject as of 1 March 2010.
Figure 5
Figure 5
Average percent success at each clinical visit for the “find the door” orientation and mobility task.
Figure 6
Figure 6
Average percent success at each clinical visit for the “follow the line” orientation and mobility task.

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