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

Abstract

Purpose This study evaluates the Argus™ II Retinal Prosthesis System in blind subjects with severe outer retinal degeneration. Design The study design is a single arm, prospective, multicenter clinical trial. Participants Thirty subjects were enrolled in the United States and Europe between 6 June 2007 and 11 August 2009. All subjects were followed for a minimum of six months and up to 2.7 years. Methods The electronic stimulator and antenna of the implant was 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 was then tacked to the epiretinal surface. Main Outcome Measures The primary safety endpoint for the trial was the number, severity, and relation of adverse events. Principal performance endpoints were assessments of visual function as well as performance on orientation and mobility tasks. Results Subjects performed statistically better with system ON vs. 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 vs. 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 successfully treated in all subjects except in one which required explantation of the device without further complications. Conclusions The long-term safety results of Second Sight’s retinal prosthesis system are acceptable and the majority of subjects with profound visual loss perform better on visual tasks with system than without.

A New Promoter Allows Optogenetic Vision Restoration with Enhanced Sensitivity in Macaque Retina

“…3 In the absence of functional photoreceptors, electrical stimulation of these inner retinal neurons was shown to enable patients to recover some visual perception and even perform some reading tasks. 4 These results collectively demonstrated that RGCs remain able to transmit information to the brain in late-stage RP. 5 However, prosthetic approaches do not yet allow sufficient resolution for face recognition or locomotion in an unknown environment.…”

Correlation of structure and function of the macula in patients with retinitis pigmentosa

“…There is no effective intervention, although several clinical trials are underway to either slow down or arrest the progression of the disease. [3][4][5][6][7] Progression in RP has traditionally been monitored in the past by assessing visual fields and full-field electroretinography. Although Goldmann visual field testing was the gold standard, more recently static perimetry using the Humphrey Field Analyzer (HFA) (programs 30-2 and 10-2) has been used for this purpose.…”

Restoration of visual function by expression of a light-gated mammalian ion channel in retinal ganglion cells or ON-bipolar cells

“…Direct electrical stimulation of the surviving inner retina has proven to be successful in restoring useful vision (6)(7)(8). One approach employs surgically implanted photovoltaic or electrode arrays to stimulate retinal ganglion cells (RGCs) (8) or bipolar cells (BCs) (6,7) directly in the inner nuclear layer (INL) of the degenerated retina, and promising results in clinical trials have led to US Food and Drug Administration approval for the Argus II device (Second Sight Medical Products, Inc.) (8).…”

“…One approach employs surgically implanted photovoltaic or electrode arrays to stimulate retinal ganglion cells (RGCs) (8) or bipolar cells (BCs) (6,7) directly in the inner nuclear layer (INL) of the degenerated retina, and promising results in clinical trials have led to US Food and Drug Administration approval for the Argus II device (Second Sight Medical Products, Inc.) (8). The electrical implants demonstrate that inner retinal neurons in blind patients can respond to appropriate stimulation and lead to a useful visual percept allowing simple navigation and object recognition.…”