The Argus II retinal prosthesis was an electronic retinal implant produced by Second Sight Medical Products. This type of prosthesis is sometimes referred to as a bionic eye.
The Argus II retinal prosthesis was developed to improve vision for users with severe retinitis pigmentosa, a genetic disorder that causes gradual loss of vision but usually not complete blindness. Symptoms include poor night vision and decreased peripheral vision, which is likely to worsen over time. Eventually, the reduction of peripheral vision can lead to tunnel vision.
Second Sight Medical seized producing the Argus II in 2020, after an investigation revealed serious user risks. They also stopped providing technical support for these devices.
The Argus II
The Argus II, which had been developed with the help of Mark Humayun from the USC Eye Institute, was designed to be smaller and easier to implant than its predecescor.
It consisted of several parts, including a digital camera, an image processor and a retina implant.
- The digital camera was mounted on eyeglass frames. It obtained images and sent them wirelessly to the computerized image processor.
- The computerized image processor was connected by cables to the retina implant.
- The implant had an 6 x 10 rectangular array of electrodes, with each electrode measuring just 200 microns in diametre. The array produced a 6 dot by 10 dot rectangular grid image in the user´s vision. The resultion was very low compared to normal vision, but allowed for visual detection of edges of large areas of high contrast. In everyday life, this can be enough to actually be able to see where door openings are, where the sidewalk ends, and similar.
The implantation process for the Argus II was carried out under general anaesthesia and took several hours. It involved the removal of the vitreous humor and any membranes on the retina where the implant was to be positioned. A tack was used to attach the implant to the retina´s surface, and cables were run through the pars plana, which is close to the area where the iris touches the sclera.
Clinical testing of the Argus II commenced in Mexico 2006, followed by a single-arm 30-person clinical trial conducted in ten medical centres in the United States and Europe on individuals with severe retinis pigmentosa. The longest follow-up on a trial subject was 38.3 months.
The individals in the 30-person clinical trial recieved an Argus II implant in one of their eyes. Vision tests were conducted with the device switched on or switched off, with the switched-off tests serving as controls.
Among the 30 individuals, nine serious adverse events were recorded. This included retinal detachment, reopening of the surgical wound, lower than normal intraocular pressure, erosion of the conjuctiva, and inflammation inside the eye.
In 2011, the Argus II was approved for commerical use and marketing in the European Union. Initially, it was only available at a limited number of clinicts in the United Kingdom, Germany, the Netherlands, France, and Italy. The EU market price was 115,000 USD.
The Argus II was available in Saudi Arabia for the EU market price.
In 2013, the Argus II was approved by the FDA in the United States, but under a humanitarian device exemption. The upper limit for the approval was a maximum of 4,000 people in the US per year.
The price was 150,000 USD. By August 2013, reimbursement payments were approved for blind Medicare recipients.
Second Sight Medical Products (SSMP) was founded in California, USA in 1998 by Alfred Mann, Samuel Williams and Gunnar Bjorg. At this point, Mann was already running a cochlear implant company with Williams as an investor.
Robert Greenberg, who was appointed CEO for the newly formed SSMP, had worked on retinal prosthetics as a graduate student at Johns Hopkins University, before joining Mann´s foundation. He would remain CEO for SSMP through 2015 and Chairman of the Board through 2018.
In 2002, clinical testing of the first version of the prosthesis, the Argus I, commenced on a group of six individuals.