Retinal Implant Restores Sight

(Ivanhoe Newswire) -- The FDA has approved the next step of a study that will help people who have lost vision from macular degeneration or retinitis pigmentosa regain some of their sight.

Researchers from the University of Southern California in Los Angeles are investigating an implanted artificial retina, called the Argus II Retinal Prosthesis System. It's the second generation of an electronic retinal implant to treat blindness by replacing photoreceptors. Photoreceptor cells in the retina process light and are required for sight. In conditions like retinitis pigmentosa, those photoreceptors deteriorate.

USC researcher Mark Humayun, M.D., Ph.D., and his team began working on the artificial implants in 2002 when they implanted six patients. Those patients received the first generation implant, which contained 16 electrodes. For the implant to work, the electrodes are attached to the retina. They work in combination with an external camera and video processing system that gives at least some sight back to patients. Dr. Humayun reports, "The devices are indeed electrically conducting and can be used by patients to detect light or even to distinguish between objects such as a cup or plate."

The updated version of the implant contains 60 electrodes, which Dr. Humayun reports he believes will result in higher resolution images for the patients. The new implant is also smaller than the original, which will reduce surgery and recovery time.

Dr. Humayun reports the implant will ultimately be used for people with age-related macular degeneration (AMD). He reports: "Perhaps what we're most excited about in this next study is, similar to the first generation ... device, we will be able to test the new device with patients at their homes, churches, schools and similar locations. The importance of this work is going to be reflected in how well this helps them regain some of their lost vision."

In the next phase of the study, Dr. Humayun will enroll patients older than 50 who have retinitis pigmentosa or age-related macular degeneration.

Ivanhoe interviewed Dr. Mark Humayun about his work on the first retinal implant system in 2003. To read that story in the Ivanhoe Archives, click here.

This article was reported by Ivanhoe.com, which offers Medical Alerts by e-mail every day of the week. To subscribe, click on: http://www.ivanhoe.com/newsalert/.

SOURCE: Presented at the American Association for the Advancement of Science annual meeting in San Francisco, Feb. 15-19, 2007