Artificial retina restores some sight for California man
When Dean Lloyd, a 68-year-old Palo Alto, Calif., lawyer, was in his mid-30s, a hereditary eye disease began taking his sight. By his late 40s, he was completely blind.
So when a clinical trial started to test an artificial retina which would restore at least partial sight, he seized the opportunity. It didn’t hurt that he was a longtime science aficionado, and fascinated by the new technology.
“For me it’s kind of a fun project, because I love science,” he said. “They say as far as guinea pigs go, I’m the prize pig.”
Scientists at Lawrence Livermore Laboratory have the lead role in advancing the technology, working in collaboration with nine other U.S. research institutions.
The Department of Energy-funded effort, begun in 2004, has yielded the most promising technology to date for restoring sight to millions of people worldwide blinded by eye diseases like age-related macular degeneration and retinitis pigmentosa, the disease that destroyed Lloyd’s vision.
And the technology shows that an electronic device can create a lasting connection with living cells such as neurons. That advance is opening the door for research into tiny, futuristic-sounding medical devices which could treat conditions like spinal cord injuries, Parkinson’s disease and brain injuries by directly stimulating nerve cells.
Because the sensitive but durable electronic array can function in the harsh environs of the human body, it also has potential uses in other fields, such as the detection of biological weapons released into the air or water.
Three years ago, Lloyd underwent a several-hour operation to implant the device into his retina, using a tiny tack the width of a human hair.
The artificial retina resembles a contact lens, and is fitted with 60 miniature electrodes which bypass damaged photoreceptor cells – called rods and cones – on his outer retina and directly stimulate his still-healthy retinal layers below.
And voila, Lloyd could see again.
His vision is far from normal. But after some tinkering with the tiny camera affixed to dark sunglasses and a video processor that’s strapped to his waist, he could make out moving cars and tell where grass ended and a sidewalk began.
The processor wirelessly relays the camera’s video signal, as well as power, to the prosthetic retina.
“It restores some sort of images,” Lloyd said.
White and reflective objects, like water, glassware and people’s eyes, stand out in particular.
So what does he see when someone’s standing in front of him?
“I see your eyes,” he said. “You flash like a cat under the bed when you put a flashlight on it.”
Lloyd is one of 38 people worldwide implanted with an artificial retina, including several implanted with a first-generation model that only had 16 electrodes.
Clinical trials with the second-generation 60-electrode version are taking place in the United States, Mexico, and Europe, with participants ranging in age from 28 to 72. All have some degree of vision restored, and many have shown significant improvements in mobility, orientation and motion detection, according to a 2009 newsletter from the Energy Department.
In a few cases, serious side effects developed, although all were resolved with treatment, the newsletter said.
Linda Moorfoot, a woman who received the 16-electrode prosthesis, told a group in 2007: “I can watch kids’ hockey and soccer games and tell which direction the game is going. I went to the top of the Eiffel Tower in Paris and saw the city lights.”
Another woman, now 57 and blind for 15 years until she received the 60-electrode implant, saw a flash in the night sky that she realized was the moon. The artificial retina also allows her to walk unaided along a sidewalk, and do chores like separating dark from light laundry.
Brian Mech, vice president of business development at Second Sight Medical Products, the Southern California company which manufactures the artificial retina, said the device will sell for around $100,000, and the surgery costs $10,000 to $15,000.
Widespread use would hinge on insurance coverage, Mech said.
The company is seeking approval for treating retinitis pigmentosa, which affects 100,000 people in the United States and 1.5 million worldwide. But it could also be used for other conditions such as age-related macular degeneration, which affects 1.6 million Americans and 8 million worldwide.
Scientists at the Livermore lab are pushing ahead with the next generation of artificial retinas, with preclinical testing under way on a model with more than 200 electrodes.
Computer simulations project that additional electrodes improve image quality, and lab scientists ultimately plan to develop one with at least 1,000 electrodes in the hopes of providing facial recognition and the ability to read, said principal investigator Satinderpall Pannu, leader of the Livermore group.
The Livermore scientists – and their collaborators in the artificial retina project at UC Santa Cruz, University of Southern California, California Institute of Technology and North Carolina State University, as well as four other national laboratories and Second Sight Medical Products – overcame high hurdles in developing the current generation of artificial retina.
The first challenge was creating a miniature electrode array, formed by metal traces less than a micrometer thick, or one-hundredth the thickness of a human hair. These are then embedded in soft, moldable silicon substrates so it conforms to the shape of the eye and doesn’t damage delicate eye tissue.
Then it had to be watertight, and made from material that would hold up to the corrosive effects of the salty water bathing the human eye.
“That’s the biggest challenge,” said Pannu. “How do you take something that’s electronic, and make it work in basically a bath of water? And not only just water, but water that’s corrosive.”
Increasing the electrode count to 1,000 poses another enormous hurdle, as the electrodes’ already tiny size and packed spacing has to decrease further to fit into the artificial retina.
For now, Lloyd is pleased with his 60-electrode implant.
During an early morning interview while he’s in the midst of a trial, Lloyd described how it’s changed life for him inside the courtroom.
He still relies on staff to assist with many functions, but feels part of the scene in a new way. He can now make out where the jury is, for example, and it’s especially easy to people wearing glasses.
“It brings a sense of the world around you, the context,” Lloyd said. “You know you’ve got some contact there.”