Fran Fulton is 66, and she’s been
fully blind for about 10 years. A few weeks ago, all that changed.
Fulton suffers from retinitis pigmentosa – a degenerative eye disease
that slowly causes light-sensitive cells in the retina to die off. Over the
course of several years she lost her sight, and for the past 10 years she
hasn’t been able to see anything at all. But in late July, Fulton was outfitted
with a system called the Argus II. A pair of camera-equipped glasses are hooked
up to electrodes implanted in her eyeball, which feed her brain visual
information. Using the system, she can now see the world again. What’s the
experience like?
“When they ‘turned me on’ so to speak it was absolutely the most
breathtaking experience,” she says. “I was just so overwhelmed and so excited,
my heart started beating so fast I had to put my hand on my chest because I
thought it was going to pop.”
As both cameras and our understanding of the visual system improve, new
techniques to restore sight to the blind are progressing too. Devices like the
Argus II are able to bypass damaged eyes to restore some vision to those who
have lost it. It’s not the same as fully restored vision, and it’s still early
days – there are only six people in the US with the Argus II – but researchers
hope that as they learn more about vision they can help those who’ve lost it
get it back.
The Argus II system is made up of three parts: a pair of glasses, a
converter box, and an electrode array. The glasses aren’t corrective, they are
simply a vehicle for the camera – and that camera is no more complicated than
the versions found in modern smart phones. The image from the camera is then
transmitted down into a converter box that can be carried in a purse or pocket.
This box sends signals to the electrode array implanted onto the patient’s
retina. Essentially, what the Argus II does is skip over the cells that retinitis
pigmentosa has killed to get visual signals to the brain.
Robert Greenberg, the president and CEO of Second Sight, the company
that developed Argus II, explains that the eye is like a multi-layer cake. On
one layer are the light-sensitive cells, called “rods” and “cones”, that
sighted people rely on to take in light and turn that into visual information.
But for those with retinitis pigmentosa, those cells are dead. “We’re bypassing
those dead cells and going to the next layer of the cake,” Greenberg explains.
This means that Argus II has to convert the information from the camera
into signals that the electrodes implanted in the eye can use, and that the
brain can interpret. Figuring out how to achieve that was the focus of
Greenberg’s PhD thesis. But there was a bigger hurdle to come, he says: working
out a way to implant electrodes onto the paper-thin retina inside the eye.
“The retina is like one-ply toilet paper,” he says. “Developing
something that can sit on the surface of the retina without damaging it is
really difficult. That was tougher than figuring out the algorithms.”
For patients, though, the whole thing is remarkably simple. The surgery
to implant the electrodes takes just a few hours and patients go home the same
day with an implant that wraps around one of their eyes and is secured by a
tiny tack the size of a human hair. After about a week to heal, the patient
returns to get the glasses, to have their new electrodes tuned, and to train
them on how to use the system. On the converter box there are knobs that let
users increase or decrease things like the brightness and contrast. Then they
go home with their new pair of eyes.
Sight beyond sight
So what do people using Argus II actually see? Greenberg says it’s best
imagined as looking like a pixelated image, or staring at a digital scoreboard
held just in front of your eyes. There are regions of light and dark that
collectively the brain recognises as an image.
Fulton, however, says it’s difficult to describe exactly what she sees.
“People say you’ll see shapes,” she says. “Well yeah but it’s the electrical
impulses, and it’s about learning how to interpret them. It’s not that it’s
hard, it’s just a learning curve. It’s something that I’m learning.”
Fulton says that mostly what she can see is areas of light and dark.
She recently had dinner with friends. When they were leaving the restaurant she
was able to hone in on a person’s light shirt. “I didn’t need to use a sighted
guide, they were in front of me and I just followed them out,” she says. Other
patients report that things like fireworks and Christmas trees are especially
visible. “I can’t wait for something to happen that I can go to fireworks, I
haven’t seen fireworks in a very long time and I am looking forward to that,”
Fran says.
Many patients, Fulton included, continue doing vision therapy to
improve their sight and train their brain to better interpret the signals.
For Fulton, who works as a disability advocate, getting around now is
so much easier. “The first time I left work with it – I work on the third floor
and there are three elevators, and I heard the bell to go down. I lined myself
up in front of the door and I walked straight in. I didn’t bump my left
shoulder, didn’t bump my right shoulder, I didn’t have to use my cane to check.
Every day it’s very exciting, and never in my lifetime did I ever think
something like this could happen.”
Fulton has long used a cane to detect obstacles in her way, but now her
awareness of her surroundings is much more detailed. “I am able to now identify
doorways and objects on the street. I can’t tell you whether it’s a flowerpot
or a homeless person collecting money, but I can tell you there’s an object
there.
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