Implanted Chip Restores Light Sensitivity to the Retina

Light is captured in the eye by specialized nerve cells called photoreceptors. These cells can be damaged by retinal degenerative diseases such as age-related macular degeneration and other retinitis pigmentosa. With current therapies, once the photoreceptors are destroyed vision loss is permanent. However, in people with photoreceptor diseases, the nerve connections to the brain often remain intact.

Recently, tiny electronic chips have been developed to help restore light sensitivity to the eye. The Argus II is the first retinal prosthesis to be implanted in Canada. This clinical research study was led by Ophthalmologist-in-Chief, Robert Devenyi. Currently the Argus II chip is used as treatment for people who have retinitis pigmentosa and no remaining functional vision.

The Argus II chip sits on the surface on the retina. A camera embedded in specialized glasses captures images, and the chip converts those images to electrical impulses, stimulating nerve cells in the retina. Although the chip does not restore normal vision, it does restore visual experience to people who were completely blind.  People who have received the implant can often see the outlines of doorways and other people, and can distinguish light from dark improving their ability to navigate through the world. With improvements in technology and ongoing rehabilitation therapy, the vision of people who use the Argus II can continue to improve.

The Argus II research study is the first research in Canada to restore some sight to people with serious photoreceptor disease. In addition to creating a new vision-restoring treatment for Canadian patients, it is also helping low vision specialists at the Donald K. Johnson Eye Institute develop rehabilitation techniques for people whose vision loss is being treated after many years of blindness. This expertise will also contribute to future clinical research trials of retinal transplants.