Sunday, December 4, 2011

[The vOICe] Implant gives new hope to the blind

Implant gives new hope to the blind.
By Tom Avril, Inquirer Staff Writer.
At first, sitting in church one Sunday, Michael Adler couldn't tell what the
whitish glow in front of him was.
Adler, 49, had been legally blind since childhood, and his vision eventually
deteriorated to pretty much zero.
But now, on the back of the pew in front of him, he saw something. And then he
realized: It was the pages of a hymnal. His new "eye" was starting to work.
Two months earlier at Wills Eye Institute, surgeons had implanted a small array
of electrodes in the back of Adler's left eye - a speck of metal no bigger than
the word eye on this page. In the last few weeks - with the aid of a small video
camera in his sunglasses that transmits images to his retinal implant - he has
begun to gain some limited vision.
"Every day, I can make out more than I could the day before," he said after a
round of follow-up tests at the University of Pennsylvania. "It's very weird
trying to get used to it."
Surgeons have implanted the devices in the retinas of 32 people around the
world. All have a severe form of retinitis pigmentosa, an inherited disease that
causes retinal degeneration.
Much like a cochlear implant enables a deaf person to perceive sound, the
retinal implant bypasses damaged cells in the eye, transmitting signals to the
same part of the brain that registers images in people with normal vision.
"It's sort of like, all the phone lines are in place and you didn't have the
phone," said Julia Haller, ophthalmologist-in-chief at Wills. "This replaces the
The resulting black-and-white images are very low-resolution, consisting of just
60 pixels - far too fuzzy for users to pick out letters on an eye chart. To
Adler, a massage therapist who lives in Mantua, Gloucester County, the face of
his 9-year-old daughter looks like a bright, featureless oval.
But he can see the outlines of doors and sidewalks, and he can pick out plates
on the dinner table.
This type of surgery is just one of several futuristic techniques that
scientists are exploring to help the blind, advances that until recently were
only a dream.
In younger patients with another type of blindness, researchers have had some
success with gene therapy, restoring a modest amount of vision by injecting
corrective genes. Two such efforts are under way at Penn: one in collaboration
with Children's Hospital of Philadelphia, the other with the University of
Florida at Gainesville.
Elephant on a typewriter.
Other methods under scrutiny include stem cells, which would regenerate the
eye's rods and cones, and cortical implants, which are a bit like what Adler has
in his eye, but which are placed directly in the brain, bypassing the eye.
"The progress is remarkable compared to what it was five years ago," said Andrew
Mariani, a program director in the National Eye Institute's division of
extramural research. "What it will be in another five or 10 years, we can just
Along the way, scientists are starting to learn new things about the brain's
plasticity - its ability to adapt.
In blind people, especially those who lose their sight at an early age, parts
of the visual cortex are commonly borrowed to enhance other senses, said the
University of Southern California's Mark S. Humayun, a leader of the
retinal-implant project.
So a big question is, when some sight is restored, are those parts of the brain
borrowed back? Humayun, a biomedical engineer and an ophthalmologist at the
Doheny Eye Institute at USC, plans to use brain scans to answer that question.
Another puzzle is why people with the implants are able to see much of anything,
because the implanted electrodes, though gossamer-thin, are still much thicker
than the natural machinery they replace.
In the center of a healthy retina, the signal from each light-sensitive cone
cell is transmitted to one ganglion cell, and ultimately through the optic nerve
to the brain.
In blind people with the implants, on the other hand, each electrode stimulates
10 to 20 ganglion cells at once, Humayun said.
"It's sort of like an elephant typing on a typewriter," said Tim Schoen,
director of preclinical research at the Foundation Fighting Blindness, which has
funded Humayun's work in the past.
But it seems to work.
Yet in a limited way, it seems to work. Some patients do better than others, but
so far all 32 have been able to see something, according to Second Sight Medical
Products, the California maker of the device.
It is called the Argus II, after the 100-eyed guardian of Greek myth.
It was designed with the help of the U.S. Department of Energy, which has
contributed $51 million and technical expertise from its national labs. DOE
scientists are now working with the company to make a higher-resolution device
with more than 200 electrodes.
The goal is to build an implant with 1,000 electrodes, though the department has
not committed funding beyond next year.
Even the current 60-electrode device is a feat of engineering, not the least
because of where it has to perform: the warm, salty surroundings of the human eye.
Adler learned of the trial from the physicians at Penn's Scheie Eye Institute,
where he had been going for years.
They felt that Adler had the motivation to cope with what would likely be a
bewildering new stimulus, and the energy to return for years of testing.
But they warned him not to hope much.
"Repeat after me: I don't have any expectations," ophthalmologist Samuel G.
Jacobson told him.
The three-hour surgery was performed June 29 by Allen Ho and Carl Regillo,
surgeons at Wills Eye and professors of ophthalmology at Thomas Jefferson
Once Adler was under anesthesia, they opened his eyelids wide and deftly cut
through the conjunctiva, the membrane that covers the white of the eye. They did
that so they could place a thin belt, called a scleral buckle, entirely around
the eyeball.
The buckle is used to hold a disk-shape receiver on one side of the eye.
Eventually, the receiver would accept signals from the camera and electronic
circuitry outside Adler's body.
Then the surgeons performed a vitrectomy, making a tiny incision in the white
of the eye, suctioning out the jelly inside and replacing it with a saline solution.
Finally, they made another small incision in the eye and inserted the electrode
implant, which was connected to the receiver by a thin cable.
The implant was then fastened to the center of Adler's retina with a microtack.
It took several weeks for his eye to heal.
On Aug. 12, he returned to Penn to try on his custom sunglasses, equipped with a
camera the size of a pencil eraser.
The switch was turned on, and at first, the sudden new stimulus was a bit much.
"It looked like I was staring into a flashlight," he said.
The device was fine-tuned, and he returned the next week, Aug. 19, to take home
the glasses for good.
By Aug. 22, he had started to get the hang of it, picking out blurry objects on
the dinner table, though he couldn't tell exactly what they were. The next day
he saw the hymnal at church.
At Penn's Scheie building, where the circular concrete walls evoke the form of
a giant eye, he has been returning each Wednesday for tests with Jacobson and
Artur V. Cideciyan, a research associate professor of ophthalmology.
In one test, he must find a white square measuring three inches across that pops
up in various spots on a computer screen.
Most of the time he gets it right, successfully touching the square with his
finger, though his hand-eye coordination is a bit rusty from years of disuse.
The implant device is small, providing only a 20-degree field of view, and so
he must swivel his head to see things. He is fully aware that the implant is
experimental, and that it may not ever make much difference in his day-to-day life.
Still, he is delighted. And Cideciyan said his performance may improve as his
brain trains itself to make sense of the newfound information.
Last week, vacationing in Ocean City, N.J., with his wife and daughter, Adler
could see the lights on the boardwalk at night.
As he walked to dinner one evening at Clancy's by the Sea, he saw what he
thought was the restaurant's dark doorway, though he had to ask someone to make
"This is all new to me," he marveled.
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