Second Sight Medical Products has unveiled positive three year results post-implant of its Argus II Retinal Prosthesis System (Argus II) from a multi-center clinical trial.
The paper titled, "Long-Term Results from an Epiretinal Prosthesis to Restore Sight to the Blind", highlights 30 subjects implanted with the Argus II at 10 centers throughout the United States and Europe.
Three types of visual function tests were performed using computer-run assessments: square localization (i.e. object detection), direction of motion (i.e. motion detection) and discrimination of oriented gratings (i.e. visual acuity).
Two types of real-world orientation and mobility (O&M) tests were also performed: a test where subjects were asked to locate and touch a door, as well as a test where subjects were asked to follow a white line on the floor. In the absence of existing validated quality of life tools for this population, a Functional Low-vision Observer Rated Assessment (FLORA) was also performed by independent visual rehabilitation experts at the request of the FDA to assess the impact of the Argus II system on the subjects’ everyday lives, including extensive interviews and tasks performed around the home.
Of the 30 subjects tested, 29 remained implanted with functioning Argus II systems at three years post-implant. Results showed that with the Argus II System, improvements in visual function and O&M were maintained out to three years.
Up to 89 percent of subjects performed statistically better with the Argus II system implanted compared with native residual vision in visual function tasks at year three. During the trial, the FLORA also demonstrated that up to 80 percent of the subjects received benefit from the system when considering both functional vision and patient-reported quality of life, and no subjects were affected negatively.
The results of the trial support the long-term safety profile and benefit of the Argus II for individuals who are blind due to retinitis pigmentosa (RP).
"The data from this study is quite remarkable for these patients who, previously, had little to no light perception, living in a world that we could consider complete darkness," said Dr. Allen C. Ho, MD FACS, Director of Retina Research, Wills Eye Hospital and Professor of Ophthalmology, Thomas Jefferson University.
"The fact that these individuals have increased independence, being able to navigate through their home, walk through doorways and cross streets, is truly life changing."
Second Sight president and CEO Robert Greenberg said: "We are thrilled to see positive results from this study, supporting the safety and benefit of the Argus II.
"The results from the trial demonstrated long-term reliability of the device, long-term benefit to the users, and an acceptable safety profile. Together, these results show that the Argus II provides a substantial visual improvement over blindness. Having this device backed by significant, long-term clinical data is cause for great hope among those individuals suffering from RP and should further our efforts across the globe in securing regulatory and reimbursement approvals."
Dr. Greenberg continued, "Of course, this is only the beginning. We are constantly making improvements in our technology and are striving to greatly improve image quality and resolution for the Argus II. With our ongoing development efforts toward the Orion I Cortical Visual Prosthesis, we hope to offer a solution for people living with blindness from nearly all causes."
Earlier results from this trial were used to gain approval of the Argus II by the FDA in addition to CE Mark in Europe. The Argus II System is the first and only retinal implant to have both approvals.
Although there are several research efforts in retinal prostheses worldwide, none have demonstrated the reliability and efficacy of such a device in a multi-centered, long-term, controlled clinical trial involving 30 subjects, as was demonstrated by the Argus II in this study.
About the Argus® II Retinal Prosthesis System
Second Sight’s Argus II System provides electrical stimulation that bypasses the defunct retinal cells and stimulates remaining viable cells inducing visual perception in individuals with severe to profound retinitis pigmentosa.
The Argus II works by converting images captured by a miniature video camera mounted on the patient’s glasses into a series of small electrical pulses, which are transmitted wirelessly to an array of electrodes implanted on the surface of the retina. These pulses are intended to stimulate the retina’s remaining cells, resulting in the perception of patterns of light in the brain. The patient then learns to interpret these visual patterns, thereby regaining some visual function.
The system is controlled by software and is upgradeable, which may provide improved performance as new algorithms are developed and tested.