From the March/April 2007 Issue
Three companies have separately developed promising high-tech implants to reverse blindness. It’s still early, writes Nick Schulz, but the results are pretty spectacular.
When Larry Hall bumped into people on the subway platform near his suburban Maryland home, he would be met with a terse, “Hey, watch where you’re going!”
“I’m sorry,” Hall would reply. “I didn’t mean to. I’m blind.”
In response, Hall would frequently hear a stammering, “But…you don’t look blind.” Without his walking cane, he may not look it, but Hall’s sight is so deteriorated that it would take him two hours to read a newspaper article.
When he was in his late 20s, eye doctors told Hall he had retinitis pigmentosa (RP), a gradual degeneration of the retina that afflicts over 1.5 million people around the world. RP is congenital, and there is currently no treatment for it. The vision of sufferers erodes, beginning at the periphery and moving toward the center—producing a severe tunnel vision effect. Just six years after being diagnosed, Hall had to stop driving.
Degenerative eye diseases like RP are major challenges for medicine. “The retina, optic nerve, and visual cortex do not lend themselves so easily to corrective measures that bring back vision,” says Gislin Dagnelie, an associate professor of ophthalmology at the Johns Hopkins School of Medicine.
But the difficulties haven’t prevented some investors, scientists, and engineers, plus the federal government, from plowing ahead. Two years ago, Hall, who is now 48, agreed to take part in a trial with a new technology. It is one of a handful of early-stage experimental techniques that could help the blind recover some of their sight.
By the end of the experimental trial, Larry Hall's vision had improved from 20/120 to 20/50.
The technology was developed by Neurotech, a small Rhode Island–based biotech firm. Results from the first clinical trials of its device—conducted jointly with the National Institutes of Health—were published last year in the Proceedings of the National Academy of Sciences. The firm’s Encapsulated Cell Technology, as it’s called, combines genetic engineering and materials science: a small pod with a porous membrane that looks like a tiny string of spaghetti is filled with genetically modified human retinal cells. The cells have been altered to secrete a protein called ciliary neurotrophic factor, which was found to protect lab rats’ retinal tissue in experiments.
Hall had the device surgically implanted in his left eye, and it remained in place for six months. By the third month, he noticed significant improvement. By the end of the trial, his vision had gone from 20/120 to 20/50. According to FDA rules, the implants had to be removed after six months. “I told my doctor, ‘Tell them Larry Hall wants to leave it in!’” he later joked. Now, more than a year after the device was removed, his left eye is still seeing at 20/50.
Neurotech recently secured $35 million in venture capital funding to continue its work. Three of the seven patients in Hall’s trial reported some improved vision capacity, and the firm has already launched a larger Phase II trial.
Two of Neurotech’s competitors are trying a different approach—directly integrating electronics into the human body. Doctors and engineers at Optobionics of Naperville, Illinois, have developed a chip that can be surgically implanted in the eye. Called the Artificial Silicon Retina (ASR), it’s a disc two millimeters wide—thinner than a human hair—made up of thousands of solar cells. It works like a kind of bionic eye: the photovoltaic cells convert light from the outside world into electrical currents that stimulate the eye’s healthy retinal cells.
Dr. Dagnelie, the Hopkins researcher, says that 20 patients are currently trying the ASR chip, including eight at his lab in Baltimore. Some of the patients have been followed for as long as two years, and Dagnelie reports that most of them are doing well. According to Optobionics, “No patient has shown signs of implant rejection, infection, inflammation, erosion, or retinal detachment related to the implanted microchip.”
At the heart of all these evolving technologies is a long, complex, and expensive discovery process.
The other firm, Second Sight, based in California, has developed an electrode array that is surgically inserted into the eye. A small camera mounted on eyeglasses captures images in front of patients, processes the video information, and then beams it wirelessly to the electronic implant in the eye, stimulating the retina. Grant Palmer, one of the principals at Second Sight, earlier helped to pioneer cochlear implants, which electrically stimulate the brain to generate hearing. He is optimistic that the lessons learned with the ear can help the eye.
Second Sight has given its implant to six totally blind patients. According to Palmer, the patients’ results have varied, but “all of them have been able to see something when they’ve been stimulated—they can make out simple edges of a doorway and things like that.” After this initial success, he says, the company is working on developing bigger implantable electrode arrays.
At the heart of all these evolving technologies is a long, complex, and expensive discovery process. None of these technologies could be developed without huge sums of money for research and patients willing to enter clinical trials. For Larry Hall, the fact that investors were willing to risk millions encouraged him to “do my part and enter a trial with a completely uncertain outcome.”
This discovery process, true to its name, often yields new knowledge in unexpected areas. Only after he participated in a trial did Hall find out that he does not, in fact, have RP. He has choroideremia, another congenital eye condition that destroys the retina. His experience has given hope to sufferers of that disease, which afflicts far fewer people than RP or macular degeneration, another condition that slowly narrows the field of vision.
Finding funds for diseases like choroideremia and RP is difficult because any successful treatment will be costly to develop and the market for treatments will be small. But America’s strong system of rewards for medical innovation has created enough incentive that some of our brightest minds are targeting these financially and technologically daunting illnesses.
Nick Schulz writes the Techno-Ideas column for The American and is editor of TCSDaily.com.