"We are pleased with both patients' progress at this point, and we are hopeful and optimistic that the artificial retina will enable them to see objects, light and people standing before them," says Jayasundera, assistant professor of ophthalmology at the U-M Medical School. "We believe the device will help them navigate a little better at home, be more independent, and have the pleasure of seeing things that the rest of us take for granted."
The device is the Argus® II Retinal Prosthesis System, developed by Second Sight Medical Products Inc. of Sylmar, Calif. The Kellogg Eye Center at the University of Michigan Health System is one of 12 Centers of Excellence around the country to offer the retinal prosthesis.
The retinal prosthesis is not activated until the patient has sufficiently recovered from surgery. The patient then undergoes training to adapt to the new vision, a process that can take from one to three months. Kellogg surgeons performed the first Argus II implant on Jan. 16 and a second implant on Jan. 22.
Linda Schulte, who received the first implant, was diagnosed with retinitis pigmentosa when she was in her 40s. Now 65, Schulte hopes the device will allow her to travel and to "enjoy life a little more." But most important, she wants to see her 10 grandchildren - to the extent that she can.
"I understand that I will not have 20/20 vision and that I won't be able to distinguish faces. But at least I will be able to know that my grandchildren are running across the yard or walking into my house. That would be a miracle to me," she says.
Retinitis pigmentosa is an inherited retinal degenerative disease that causes slow but progressive vision loss due to a gradual loss of the light-sensitive retinal cells called rods and cones. Patients with RP experience gradual loss of side vision and night vision, and later of central vision, which can result in near blindness.
The Argus® II Retinal Prosthesis System is surgically implanted in one eye. The individual wears glasses equipped with a camera that captures images and converts them into a series of small electrical pulses. The pulses are transmitted wirelessly to the prosthesis and its array of electrodes on the surface of the retina. These pulses are intended to stimulate the retina's remaining cells, resulting in the corresponding perception of patterns of light in the brain. The patient then learns to interpret these visual patterns, thereby regaining some visual function.
In an earlier clinical study of the Argus II, most participants were able to perform basic activities better with the retinal prosthesis than without it. Many were able to locate lights and windows, follow lines in a crosswalk, or avoid running into things as they walked. Some could sort laundry or determine where other people were located in a room, and about half of the subjects were able to read very large letters (about 9 inches high).
To be eligible to receive the retinal prosthesis, individuals must be 25 or older with end-stage retinitis pigmentosa that has progressed to the point of having "bare light" or no light perception in both eyes.
Kellogg Retinal Implant Team: Kari Branham, MS, CGC, Carol George, R.N., John Heckenlively, M.D., Ashley Howson, MS, OTR/L, Thiran Jayasundera, M.D., Mark Johnson, M.D., Naheed Khan, Ph.D., Kari Magill, R.N., Donna Wicker, OD, David Zacks, M.D., Ph.D.
Learn more about eligibility requirements for Argus II:
Kellogg Retinal Dystrophy Clinic
SOURCE University of Michigan Kellogg Eye Center
University of Michigan Kellogg Eye Center
Web Site: http://www.kellogg.umich.edu/
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