WALNUT CREEK, CALIF. -- When Dean Lloyd, 68, a Palo Alto, Calif., lawyer, was in his mid-30's, a hereditary eye disease began taking his sight. By his late 40's, he was completely blind.
So, when a clinical trial started to test an artificial retina that 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 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 for restoring sight to millions of people worldwide blinded by eye diseases such as age-related macular degeneration and retinitis pigmentosa, the disease that destroyed Lloyd’s vision.
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 that could treat conditions such as 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 that bypass damaged photoreceptor cells — called rods and cones — on his outer retina and directly stimulate his still-healthy retinal layers below.
While Lloyd could see again, his vision was far from normal. But after tinkering with the 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 and power to the prosthetic retina.
"It restores some sort of images,” Lloyd said.
White and reflective objects, such as 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,” Lloyd said. "You flash like a cat under the bed when you put a flashlight on it.”
He’s one of 38 people worldwide implanted with an artificial retina, including several implanted with a first-generation model that had 16 electrodes. Clinical trials with the second-generation, 60-electrode version are taking place in the U.S., Mexico and Europe, with participants ages 28 to 72. All have some degree of vision restored, and many have shown significant improvements in mobility, orientation and motion detection, a 2009 newsletter from the Energy Department on the artificial retina project said.
In a few cases, serious side effects developed, but all were resolved with treatment, the newsletter stated.
Linda Moorfoot, 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 such as separating dark from light laundry.
Brian Mech, vice president of business development at Second Sight Medical Products, the Southern California company that manufactures the artificial retina, said it will sell for about $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 in the U.S. and 1.5 million worldwide. But it also could be used for 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.
McClatchy-Tribune Information Services