The device, made by privately held Second Sight Medical Products Inc of Sylmar, California, is intended to replace the function of light-sensing cells in the retina destroyed by retinitis pigmentosa, an inherited degenerative disease that affects about 100,000 people nationwide.
In a healthy eye, the retina, which lines the back of the inner eye, works a bit like film in a camera, converting images that come through the eye's lens into electronic signals that are relayed to the optic nerve in the brain.
To replicate this, the Argus II device consists of special glasses outfitted with a video camera and a video processing unit that sends signals to a wireless receiver implanted in the eye.
Although it does not completely restore vision, the implant helps with daily activities, such as locating objects and recognizing large letters and shapes.
"In the patients that have been implanted to date, the improvement in the quality of life has been invaluable," said Mark Humayun of the University of Southern California's Keck School of Medicine and USC's Viterbi School of Engineering, who helped develop the device.
The Argus II was approved for use in Europe in 2011 and has been implanted in 30 patients in a clinical trial that began in 2007. In October, advisers to the FDA voted unanimously to approve the device.
Brian Mech, vice president of business development at the company, said the system will cost more than $100,000 when it is launched in the United States, sometime this year.
Mech said the company is working with insurance companies and Medicare to win coverage and ease out of pocket expenses for patients.
The Argus II is intended to replace the function of light-sensing photoreceptor cells, which gradually become degraded in retinitis pigmentosa.
To restore vision, signals from the camera are sent to the retina, where they travel to the optic nerve in the brain. The brain then receives these signals and interprets them as a visual picture.
The FDA approved the system as a humanitarian use device, an approval that is limited to fewer than 4,000 people in the United States each year. For this kind of approval, companies must show the device is safe and the probable benefit outweighs the risks.
In the clinical trial, most of the 30 participants improved in their ability to see and touch a square on a white field, detect the direction of a motion, recognize large letters and sentences, see street curbs and even match socks.
To receive the Argus II device, patients must have had the ability to see forms in the past and must be willing and able to get the recommended follow-up care and training.
The device is limited to adults 25 or older, with severe to profound retinitis pigmentosa who have no light perception or bare light perception, in which they can perceive light but cannot tell where it is coming from.
The team plans to keep improving the treatment, which they hope will ultimately be used to treat age-related macular degeneration.
Mech said while there are many academic centers working on retinal implants, getting the system to market took 14 years, $200 million, and a lot of "intestinal fortitude." (Reuters)
REUTERS
