For the past 20 years, researchers working for the Boston Retinal Implant Project have been developing a bionic eye implant that could restore sight for individuals who have age-related blindness.
The implant builds on the development of miniaturized electronics technology. A small chip is surgically implanted behind the retina at the back of the eyeball, and an ultra-thin wire strengthens the damaged optic nerve. The wire transmits light and images to the brain’s vision system for normal processing.
Other than the implanted chip and wire, most of the device sits outside the eye. Individuals would wear special glasses that contain a tiny battery-powered camera and a transmitter that sends images to the chip behind the retina.
The chip is enclosed in a titanium casing, making it water-proof and corrosion-proof, and will hopefully last for at least 10 years inside the eye.
As the researchers explain, the bionic eye would only work for individuals who once had sight, since the brain must know how to process visual information. The optic nerve must also be at least partly functional. In many individuals that are born blind, the optic nerve has never been used, and the vision part of the brain focuses on other abilities, such as hearing and touch.
Nevertheless, many people could potentially benefit from the technology. Age-related macular generation is the leading cause of blindness in the industrialized world, with about 2 million Americans suffering from the condition. The device could also help individuals suffering from retinitis pigmentosa (a genetic condition), but it would not work for patients with glaucoma.
The researchers aren’t sure exactly how much the device could help, either. It definitely won’t restore perfect vision, but it will hopefully give people a sense of their surroundings. One day, the technology might enable people to recognize faces and facial expressions.
“The thing is to significantly improve the quality of life for blind patients,” said Joseph Rizzo of the Massachusetts Eye and Ear Infirmary, who has co-directed the project with MIT’s John Wyatt since 1988. “What level of achievement that would actually be is hard to know. The idea of not having to use the white cane – to walk around, find the sidewalk, not run into a telephone pole, not walk into a car. Being able to navigate safely in an unfamiliar environment, that’s the big topic.”
One of Rizzo’s patients, Chris Leghorn, has Leber’s Amaurosis, a degenerative disease of the retina, and is progressively losing her vision.
“The one thing that’s really important is that sometimes the smallest improvement can make a big difference in your life,” she said. “Small improvements should not be seen as not good enough. When you have limited vision, a small amount is big. When you lose a small amount of vision, it’s big. So I can only imagine how gaining a tiny part of it back would be for me.”
This summer, the researchers plan to test the implants on animals. Within the next few years, they hope to start doing human surgeries.
The Boston Retinal Implant Project consists of 36 researchers from several institutions, including MIT, the Massachusetts Eye and Ear Infirmary, and the V.A. Medical Center in Boston.