Joelle Swyka steps onto the floating dock. She feels dizzy and disoriented. This isn鈥檛 like the stable wooden dock back home in Pittsburgh, she thinks. She鈥檚 guided off of the dock and steps into a boat, where she finds her seat alongside her teammates and takes up her paddle.
About 200 miles away, Carol Gaul waits in her apartment for a senior-services van to take her to the grocery store. She wishes she could just drive herself, like she used to. While she waits, she listens to her iPod. She turns on Led Zeppelin, one of her favorite bands, and thinks back to when she saw them perform live in the 鈥�70s.
At Carnegie Mellon, checks his inbox. He鈥檚 not surprised when he finds several new emails from people across the country. The senior systems scientist at the (ICES) regularly gets emails like these. Each tells a different story, but they all have one thing in common. They are all from people wondering if he might be able to help them see again.
An air horn sounds, and Swyka pushes off with her team, the Wishing Dragons, as other colorful dragon-shaped boats take to the water. Dragon boat racing is a traditional Chinese sport that dates back more than 2,000 years. A drummer at the helm maintains a beat to keep all the rowers moving as one. Drums echoing, water splashing, cheers and whoops from the shore鈥擲wyka is in her element. The drum beat keeps her in sync with her teammates.
She is one of an estimated 80 million Americans who have a potentially blinding eye disease, according to the Centers for Disease Control and Prevention. Her particular condition is retinitis pigmentosa, an untreatable and incurable inherited disease that affects about 100,000 Americans. It usually shows up during adolescence and gradually causes the cells of the retina to break down.
The retina lines the inside of the back portion of the eye and connects to the brain through the optic nerve. Unlike other parts of the eye, the retina is actually part of the central nervous system. Although it has the thickness and consistency of a wet Kleenex, this thin, delicate tissue is densely packed with millions of light-sensitive cells called rods and cones. Rods provide black-and-white vision, enabling us to see in dim lighting and giving us peripheral vision. Cones give us color and sharp, detailed central vision.
In a healthy eye, rods and cones capture incoming light, like film in a camera, and turn it into electrical signals. The signals are then relayed through the retina鈥檚 neural pathway to the optic nerve, where they leave the eye and travel to the brain to produce the end result鈥攙ision.
But in someone with retinitis pigmentosa, the rods and cones degenerate and die. Light that enters the eye never makes it to the brain. Swyka鈥檚 retina began deteriorating at the age of three, when she developed the disease as part of an underlying rare genetic disorder. Her life changed drastically during the past two years as her vision began to rapidly deteriorate, leaving her almost completely blind with only minimal tunnel vision, like looking through a straw.
She has learned to live with blindness, using a cane to get around and auditory software to do things like study on a computer, send text messages on her smartphone, and watch movies. Yet, every day has much sadness for the high school senior. Navigating the crowded hallways of her high school with a cane, she bumps into classmates. She can find her way to a familiar table in the cafeteria, but she can鈥檛 look around to find anyone to sit with. It鈥檚 hard to make friends.
Despite the obstacles, Swyka says she tries to stay positive, looking for outlets. When she no longer had enough vision to compete for her high school track team, she discovered dragon boat racing, what she calls an 鈥渙pen window鈥� after a 鈥渃losed door.鈥� On the water, she escapes the harsh realities of being blind in a vision-centric world.
Gaul is also looking for such open windows. Living in southern California, she was in her early 鈥�70s when she began to notice that street signs were hard to read. Then she cut her fingers chopping vegetables one day. After an exam with her eye doctor, she learned it wasn鈥檛 a matter of getting a stronger prescription for her eyeglasses. She was diagnosed with macular degeneration, a retinal disease that is one of the leading causes of vision loss in people older than 40. There are two types of the disease: wet and dry. Gaul has the wet form. Abnormal blood vessels behind her retina leaked blood and fluid, which damaged the rods and cones of her macula, the area in the retina responsible for giving us sharp, detailed central vision. In dry macular degeneration, the macula basically thins and wears out. Either type, wet or dry, can cause severe vision loss, according to the .
Understandably, Gaul was frightened at the thought of going completely blind. As her condition worsened and daily activities became too hard to handle alone, she decided to give up her life in southern California and relocate to Pittsburgh to be closer to her children.
Unlike Swyka, Gaul can still see peripherally. As with many others with advanced macular degeneration鈥攚et or dry鈥攁 fuzzy, gray spot blurs her central vision, making it difficult to recognize faces, meet new people, read, or drive. In other words, people with macular degeneration lose their ability to see the big 鈥淓鈥� on the vision chart, explains ophthalmologist Joel Schuman, director of the , even though they can still see enough to get around with what remains of their peripheral vision.
Gaul, like Swyka, has learned to adapt, recognizing people by voices and listening to audio books. Yet, for Gaul, who professes she is still young at heart, losing her vision as she grows older is debilitating. She鈥檚 had to forfeit much of her daily independence. She鈥檚 not alone. By 2020, the number of people with either form of macular degeneration is expected to nearly double to about 3 million in the United States as the population ages. Millions more run the risk of developing the disease.
Retinal diseases, unlike cataracts or glaucoma, don鈥檛 have a viable treatment. The optic nerve is about the size of an eraser on the tip of a pencil, and it has approximately one million connections with the retina, which is what makes a retinal transplant realistically impossible. Having spent more than a decade searching for some sort of breakthrough for their daughter, the Swykas know this all too well. Like many others, when they came across an article about Shawn Kelly鈥檚 work at Carnegie Mellon, they sent him an email.
At ICES, Kelly is turning what was once the stuff of science fiction into reality. He鈥檚 developing an implantable retinal prosthesis with the capability to restore functional vision to those who have lost most of their sight from retinal disease and damage. Where the technology stands now, it would let someone like Swyka see shapes and forms, figure and movement鈥攅nough to interact with people, walk around safely in unfamiliar environments, identify objects, and possibly even see colors.
The wireless system has three main pieces: a digital video camera propped up by a pair of non-prescription glasses, a portable pack that contains a battery and processor similar to an iPhone, and a surgical implant that wraps around the eye. The portable pack refines pixels captured by the camera and wirelessly transmits data and power to the implant on the eye, where an implanted microchip enclosed in a tiny, airtight titanium case sitting on top of the eyeball turns incoming data into electrical pulses, much like rods and cones would in a healthy eye. An electrical current leaves the microchip and travels to an array of more than 256 electrodes implanted behind the retina, which reach their final destination: retinal nerve cells that lead to the optic nerve. In essence, the electrodes are bypassing the rods and cones. The electrodes鈥攎etal conductors commonly used as stimulators in biomedical devices and in electrocardiographs and defibrillators鈥攁re microfabricated to be no thicker than the width of an eyelash. It would take approximately one million electrodes鈥攁bout a 1:1 ratio with nerves鈥攖o provide 20/20 vision. That technology is a long way off, says Kelly.
At ICES, he heads development of the 256+ prototype, the highest count yet achieved in the field for this type of implant. ICES is a multidisciplinary initiative that brings together engineering technologies at the with interdepartmental research at Carnegie Mellon. Kelly came to ICES in early 2012, bringing with him his expertise in neural microstimulation electronics and systems. Holding a PhD in electrical engineering from MIT, he spent more than a decade working on several generations of retinal electrode implants with the , a collaboration among Harvard Medical School, the , and MIT, which put the field of retinal prostheses on the map in the late 鈥�80s.
After taking a class taught by one of the founders of the Boston project while he was a grad student at MIT, Kelly knew he wanted to tackle the complex engineering challenges involved in developing a retinal prosthesis. That meant transforming early prototypes into an elegant and wireless miniature system that could be implanted into the saltwater environment of the eye and last for longer than a decade鈥攍ike 鈥渢aking a toaster, throwing it in the ocean, and expecting it to work,鈥� says Schuman.
As they scaled up the electrode count past 200, Kelly had to meet the growing energy demands of the device. Unless you鈥檙e Dr. Frankenstein, most people are skittish about pumping electricity through the body, and rightly so, he says. Enough energy is needed to stimulate the nerve cells, but too much can damage or electrocute the delicate tissue of the retina.
He created a state-of-the-art circuit design and wireless/data telemetry system, optimizing it to efficiently and safely deliver a low-power current. His robust wireless technology received international recognition when he received 鈥淏est Paper Award鈥� at an conference in 2009, the world鈥檚 largest professional association for the advancement of technology.
More recently, the awarded him a $1.1 million grant for further technical development of the wireless system, and he hopes to receive additional funding to move the current prototype into clinical trials. He is currently developing a novel charge-balanced stimulator circuit that will make neural stimulators safer for long-term stimulation. While a 1 million electrode device may one day be realized, the goal for now, he says, is to first break 1,000, which would create functional vision.
Getting there will require pushing implantable medical device technology forward in several areas at once, says Doug Shire, Engineering Manager for the , where he began working with Kelly through the Boston Retinal Implant Project. Such technology includes the fabrication of the electrodes and the protective miniature packaging of the implanted microchip that includes Kelly鈥檚 circuit design. Take for example the implant鈥檚 electronic packaging surrounding the microchip, which Shire has been developing. It needs to be airtight, or 鈥渉ermetically sealed,鈥� in order to protect it within the eye鈥檚 watery environment. Right now, the microfabrication techniques to seal a 1,000-count device just don鈥檛 exist.
Kelly believes that a higher-count implant, once that technology does exist, could help people with macular degeneration, like Gaul, to recognize faces and read. Currently, he is confident that the 256+ will help mostly blind retinitis pigmentosa patients like Swyka. Depending on how future clinical trials go, he expects the device to be available within five years, which he鈥檒l distribute through his startup company .
For the Swyka family, that is welcome news. 鈥淭here is always a light at the end of the tunnel, even when you can鈥檛 see,鈥� says her mom.
Danielle Commisso (DC鈥�06) is a Pittsburgh-based freelance writer and a regular contributor to this magazine.
Related Links:
听
