Implant Restores Some Vision in Retinitis Pigmentosa
Thirty-seven years after being diagnosed with retinitis pigmentosa, a 50-year-old woman has had her vision partially restored with an experimental electronic eye implant. The implant procedure was performed at New York-Presbyterian Hospital/Columbia University Medical Center.
The electronic eye implant was designed to restore limited vision in people who have retinal disease. Retinitis pigmentosa is a genetic condition in which the photoreceptor cells (rods and cones) of the retina, which receive light and translate it into signals that are sent to the brain through the optic nerve, gradually deteriorate. Individuals who have retinitis pigmentosa eventually experience severe vision loss or total blindness.
Prevent Blindness America reports that approximately 400,000 people in the United States have retinitis pigmentosa. The first symptoms often appear during childhood and consist of a gradual loss of side (peripheral) vision and a gradual inability to adjust to dim light (night blindness). Currently there is no known cure for the disease.
Thus far, the electronic eye implant has been available only as part of a clinical trial being conducted at six locations across the country. The implant stimulates retinal cells, allowing people who are functionally blind to potentially distinguish light from dark, navigate in their surroundings, determine figures, and recognize visual patterns. Currently the implant is not capable of restoring full vision, but it can offer people who have retinitis pigmentosa more independence.
Unlike glaucoma, optic nerve disease, or diabetic retinopathy, which typically involve more severe retinal damage, retinitis pigmentosa affects the outer layer of retinal cells only, leaving the underlying layers healthy and capable of conducting electricity. The eye implant contains 60 minute electrodes that send electrical impulses to these healthy retinal cells. Thus far about 20 patients have received the implant. Individuals who have the implant must also wear a pair of sunglasses that has a tiny camera and transmitter mounted on it, and wear a wireless microprocessor and battery pack on their belt.
Once individuals with retinitis pigmentosa have the eye implant, they also need to undergo visual training so they can learn to use or accept the images their eyes are receiving. This rehabilitation process can take six months to a year. Currently, rehabilitation for the patient who received the implant at New York-Presbyterian/Columbia is taking place at Lighthouse International, a nonprofit vision rehabilitation and research organization. The researchers involved in the trials hope their efforts will eventually help the hundreds of thousands of people who have retinitis pigmentosa regain some of their vision.
Prevent Blindness America
New York-Presbyterian/Columbia University Medical Center