[Blindtlk] FDA approves first retinal implant for adults with rare genetic eye disease

[Daniel Garcia]

FDA approves first retinal implant for adults with rare genetic eye disease

For Immediate Release: Feb. 14, 2013

http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm339824.htm

The U.S. Food and Drug Administration today approved the Argus II Retinal
Prosthesis System, the first implanted device to treat adult patients with
advanced retinitis pigmentosa (RP). The device, which includes a small video
camera, transmitter mounted on a pair of eyeglasses, video processing unit
(VPU) and an implanted retinal prosthesis (artificial retina), replaces the
function of degenerated cells in the retina (a membrane inside the eye) and
may improve a patient's ability to perceive images and movement. The VPU
transforms images from the video camera into electronic data that is
wirelessly transmitted to the retinal prosthesis.    
RP is a rare genetic eye condition that damages the light-sensitive cells
that line the retina. In a healthy eye, these cells change light rays into
electrical impulses and send them through the optic nerve to the area of the
brain that assembles the impulses into an image. In people with RP, the
light-sensitive cells slowly degenerate resulting in gradual loss of side
vision and night vision, and later of central vision. The condition can lead
to blindness.
"This new surgically implanted assistive device provides an option for
patients who have lost their sight to RP - for whom there have been no
FDA-approved treatments," said Jeffrey Shuren, M.D., director of the FDA's
Center for Devices and Radiological Health. "The device may help adults with
RP who have lost the ability to perceive shapes and movement to be more
mobile and to perform day-to-day activities." 
The Argus II system is intended for use in adults, age 25 years or older,
with severe to profound RP who have bare light perception (can perceive
light, but not the direction from which it is coming) or no light perception
in both eyes, evidence of intact inner layer retina function, and a previous
history of the ability to see forms. Patients must also be willing and able
to receive the recommended post-implant clinical follow-up, device fitting,
and visual rehabilitation. 
In addition to a small video camera and transmitter mounted on the glasses,
the Argus II Retinal Prosthesis System has a portable video processing unit
(VPU) and an array of electrodes that are implanted onto the patient's
retina. The VPU transforms images from the video camera into electronic data
that is wirelessly transmitted to the electrodes. The electrodes transform
the data into electrical impulses that stimulate the retina to produce
images. While the Argus II Retinal Prosthesis System will not restore vision
to patients, it may allow them to detect light and dark in the environment,
aiding them in identifying the location or movement of objects or people.
The FDA approved the Argus II Retinal Prosthesis System as a humanitarian
use device, an approval pathway limited to those devices that treat or
diagnose fewer than 4,000 people in the United States each year. To obtain
approval for humanitarian use, a company must demonstrate a reasonable
assurance that the device is safe and that its probable benefit outweighs
the risk of illness or injury. The company also must show that there is no
comparable device available to treat or diagnose the disease or condition. 
The FDA reviewed data that included a clinical study of 30 study
participants with RP who received the Argus II Retinal Prosthesis System.
Investigators monitored participants for adverse events related to the
device or to the implant surgery and regularly assessed their vision for at
least two years after receiving the implant.
Results from the clinical study show that most participants were able to
perform basic activities better with the Argus II Retinal Prosthesis System
than without it. Some of the activities tested included locating and
touching a square on a white field; detecting the direction of a motion;
recognizing large letters, words, or sentences; detecting street curbs;
walking on a sidewalk without stepping off; and matching black, grey and
white socks.
Following the implant surgery, 19 of the 30 study patients experienced no
adverse events related to the device or the surgery. Eleven study subjects
experienced a total of 23 serious adverse events, which included erosion of
the conjunctiva (the clear covering of the eyeball), dehiscence (splitting
open of a wound along the surgical suture), retinal detachment,
inflammation, and hypotony (low intraocular pressure). 
Three government organizations provided support for the development of the
Argus II. The Department of Energy, National Eye Institute at the National
Institutes of Health and the National Science Foundation collaborated to
provide grant funding totaling more than $100 million, support for material
design and other basic research for the project.
Second Sight Medical Products, Inc. is based in Sylmar, Calif.