New Research: The Argus II Retinal Prosthesis (Bionic Eye) Is Safe, Effective, and Improves Visual Function
by Maureen Duffy
New clinical trial results from the Argus II Study Group, an international consortium of eye and vision researchers, confirm that the Argus II, also called the "bionic eye," is a safe, reliable, and effective device that "significantly improves visual function and quality of life for people blinded by retinitis pigmentosa."
The latest research, entitled Long-Term Results from an Epiretinal [i.e, "on," "upon," "near," or "against" the retina] Prosthesis to Restore Sight to the Blind, has been published online ahead of print, as an open-source article in the July 2015 edition of Ophthalmology, the official journal of the American Academy of Ophthalmology. Ophthalmology publishes original, peer-reviewed research in ophthalmology, including new diagnostic and surgical techniques, the latest drug findings, and results of clinical trials.
The authors are Allen C. Ho, MD; Mark S. Humayun, MD, PhD; Jessy D. Dorn, PhD; Lyndon da Cruz, MD; Gislin Dagnelie, PhD; James Handa, MD; Pierre-Olivier Barale, MD; José-Alain Sahel, MD; Paulo E. Stanga, MD; Farhad Hafezi, MD, PhD; Avinoam B. Safran, MD; Joel Salzmann, MD; Arturo Santos, MD, PhD; David Birch, PhD; Rand Spencer, MD; Artur V. Cideciyan, PhD; Eugene de Juan, MD; Jacque L. Duncan, MD; Dean Eliott, MD; Amani Fawzi, MD; Lisa C. Olmos de Koo, MD; Gary C. Brown, MD; Julia A. Haller, MD; Carl D. Regillo, MD; Lucian V. Del Priore, MD; Aries Arditi, PhD; Duane R. Geruschat, PhD; and Robert J. Greenberg, MD, PhD. All authors are members of the Argus II Study Group.
Some Background on the Argus II
The Argus II was developed by Second Sight Medical Products, Inc., of Lausanne, Switzerland and Sylmar, California to treat adults with severe to profound retinitis pigmentosa (RP). RP is a rare, inherited degenerative disease that damages light-sensitive cells in the retina, resulting in decreased vision at night or in low light; loss of side (peripheral) vision; and loss of central vision as the disease progresses. At present, there is no cure for RP.
The retina is the light-sensitive tissue that lines the inside surface of the eye. Cells in the retinal tissue convert incoming light into electrical impulses. These electrical impulses are carried by the optic nerve to the brain, which finally interprets them as visual images. The Argus II is not a cure for RP; instead, it is intended to replace the function of the light-sensing cells that have been damaged and/or degraded by the disease.
The Argus II device consists of the following components:
- a small video camera
- a transmitter mounted on a pair of eyeglasses
- a video processing unit (VPU)
- an artificial retina (the implanted retinal prosthesis, which is an array of electrodes)
The video camera images are transformed into electronic data by the VPU that sends signals to a wireless receiver implanted in the eye (the retinal prosthesis electrodes). The electrodes allow the electronic signals to bypass the damaged retina and transmit directly to the brain, where they are interpreted as visual images.
The cost of the Argus II is approximately $100,000; additional fees include the implantation surgery and training to use the device. The Second Site website provides an illustrated system overview, including a video animation.
On February 14, 2013, Second Sight received approval as a Humanitarian Use Device (HUD) from the U.S. Food and Drug Administration (FDA) for the Argus II. The HUD designation is an approval specifically for devices intended to benefit small populations and/or rare conditions. On August 15, 2013, Second Sight announced that the Argus II was approved by the Centers for Medicare and Medicaid Services (CMS), beginning October 1, 2013. You can learn about all ongoing Argus® II clinical trials at the ClinialTrials.gov website.
Who Is Eligible for the Argus II?
The Argus II is implanted in a single eye, typically the worse-seeing eye. It is indicated for persons with severe to profound RP who meet the following criteria:
- Age 25 or older
- Have bare light or no light perception in both eyes: Bare light perception is the ability to perceive light, but not the direction from which the light is coming. If the person has no residual light perception, then evidence of intact inner layer retina function must be confirmed.
- A previous history of useful form vision
- Be aphakic or pseudophakic: Aphakic means that the eye is lacking its natural lens. Pseudophakic means that the eye has been fitted with an artificial lens implant (as in cataract surgery) to replace the missing or surgically removed natural lens.
- If the person is phakic (i.e., has a natural lens or an artificial lens implant) prior to the Argus II implant surgery, the lens will be removed during the implant procedure.
- Be willing and able to receive the recommended post-implant clinical follow-up, device fitting, and visual rehabilitation.
About the Latest Argus II Research
Excerpted from Bionic eye clinical trial results show long-term safety, efficacy, of vision-restoring implant, via Medical Xpress:
The latest three-year clinical trial results of the retinal implant, popularly known as the "bionic eye," have proven the long-term efficacy, safety and reliability of the device that restores vision in those blinded by a rare, degenerative eye disease. The findings show that the Argus II significantly improves visual function and quality of life for people blinded by retinitis pigmentosa.
To further evaluate the safety, reliability and benefit of the device, a clinical trial of 30 people, aged 28 to 77, was conducted in the United States and Europe. All of the study participants had little or no light perception in both eyes.
The researchers conducted visual function tests using both a computer screen and real-world conditions, including finding and touching a door and identifying and following a line on the ground.
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.
The visual function results indicated that up to 89 percent of the subjects performed significantly better with the device. The FLORA found that among the subjects, 80 percent received benefit from the system when considering both functional vision and patient-reported quality of life, and no subjects were affected negatively.
After one year, two-thirds of the subjects had not experienced device- or surgery-related serious adverse events. After three years, there were no device failures. Throughout the three years, 11 subjects experienced serious adverse events, most of which occurred soon after implantation and were successfully treated. One of these treatments, however, was to remove the device due to recurring erosion after the suture tab on the device became damaged.
More about the Study from Ophthalmology
From the article abstract, with the full open-access article (PDF) available online:
Purpose: Retinitis pigmentosa (RP) is a group of inherited retinal degenerations leading to blindness due to photoreceptor loss. Retinitis pigmentosa is a rare disease, affecting only approximately 100,000 people in the United States. There is no cure and no approved medical therapy to slow or reverse RP.
The purpose of this clinical trial was to evaluate the safety, reliability, and benefit of the Argus II Retinal Prosthesis System in restoring some visual function to subjects completely blind from RP. We report clinical trial results at one and three years after implantation.
Participants: There were 30 subjects in 10 centers in the United States and Europe. Subjects served as their own controls, that is, implanted eye versus fellow eye, and "system on" versus "system off" (native residual vision).
Methods: The Argus II System was implanted on and in a single eye (typically the worse-seeing eye) of blind subjects. Subjects wore glasses mounted with a small camera and a video processor that converted images into stimulation patterns sent to the electrode array on the retina.
Main Outcome Measures: The primary outcome measures were safety (the number, seriousness, and relatedness of adverse events) and visual function, as measured by three computer-based, objective tests.
Results: A total of 29 of 30 subjects had functioning Argus II Systems implants three years after implantation. Eleven subjects experienced a total of 23 serious device- or surgery-related adverse events. All were treated with standard ophthalmic care. As a group, subjects performed significantly better with the system on than off on all visual function tests and functional vision assessments.
Conclusions: The three-year results of the Argus II trial support the long-term safety profile and benefit of the Argus II System for patients blind from RP. Earlier results from this trial were used to gain approval of the Argus II by the Food and Drug Administration and a CE mark in Europe. The Argus II System is the first and only retinal implant to have both approvals.
VisionAware will continue to report Argus II research updates as they become available.
Additional Argus II Information at VisionAware
- The Argus II: Fact or Science Fiction? A "Bionic Eye" Pioneer Tells Her Story
- New European Research: Is the Argus II (the "Bionic Eye") Cost-Effective?
- The Argus II Retinal Prosthesis ("Bionic Eye") Receives Medicare Approval
- Meet Aries Arditi, Ph.D., Founder and Principal Scientist of Visibility Metrics, LLC
- Meet Duane Geruschat, Ph.D. and the Argus II Retinal Prosthesis at Second Sight Medical Products
Argus II images provided by Second Sight Medical Products, Inc. Used with permission.
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