How well can you see with your ears? Device offers new alternative to blind people

A device that trains the brain to turn sounds into images could be used as an alternative to invasive treatment for blind and partially-sighted people, researchers at the University of Bath have found.

The vOICe sensory substitution device is a revolutionary tool that helps blind people to use sounds to build an image in their minds of the things around them.

A research team, led by Dr Michael Proulx, from the University’s Department of Psychology, looked at how blindfolded sighted participants responded to an eye test using the device.

They were asked to perform a standard eye chart test called the Snellen Tumbling E test, which asked participants to view the letter E turned in four different directions and in various sizes. Normal, best-corrected visual acuity is considered 20/20, calculated in terms of the distance (in feet) and the size of the E on the eye chart.

The participants, even without any training in the use of the device, were able to perform the best performance possible, nearly 20/400. This limit appears to be the highest resolution currently possible with the ever-improving technology.

Dr Michael Proulx said: “This level of visual performance exceeds that of the current invasive techniques for vision restoration, such as stem cell implants and retinal prostheses after extensive training.

"A recent study found successful vision at a level of 20/800 after the use of stem cells. Although this might improve with time and provide the literal sensation of sight, the affordable and non-invasive nature of The vOICe provides another option.

"Sensory substitution devices are not only an alternative, but might also be best employed in combination with such invasive techniques to train the brain to see again or for the first time."

Bionic eye prototype unveiled by Victorian scientists and designers

A team of Australian industrial designers and scientists have unveiled their prototype for the world’s first bionic eye.

It is hoped the device, which involves a microchip implanted in the skull and a digital camera attached to a pair of glasses, will allow recipients to see the outlines of their surroundings.

If successful, the bionic eye has the potential to help over 85 per cent of those people classified as legally blind. With trials beginning next year, Monash University’s Professor Mark Armstrong says the bionic eye should give recipients a degree of extra mobility.

"There’s a camera at the front and the camera is actually very similar to an iPhone camera, so it takes live action for colour," he told PM. "And then that imagery is then distilled via a very sophisticated processor down to, let’s say, a distilled signal.

"That signal is then transmitted wirelessly from what’s called a coil, which is mounted at the back of the head and inside the brain there is an implant which consists of a series of little ceramic tiles and in each tile are microscopic electrodes which actually are embedded in the visual cortex of the brain."

Professor Armstrong says is it is hoped the technology will help those who completely blind, enabling them to navigate their way around.

"What we believe the recipient will see is a sort of a low resolution dot image, but enough… [to] see, for example, the edge of a table or the silhouette of a loved one or a step into the gutter or something like that," he said.

"So the wonderful thing, if our interpretation of this is correct - because we don’t know until the first human trial - [is] it’ll of course enable people that are blind to be reconnected with their world in a way.

"There’s a number of different settings … so you could set it to floor mapping for example and it creates a silhouette around objects on the floor so that you can see where you’re going."

A challenge the designers have had to overcome is ensuring the product was lightweight, adjustable and enabled users to feel good about themselves.

"We want to make it comfortable and light weight and adjustable so that different sized heads and shapes will still manage it well and have those sort of nice aspects," Professor Armstrong said.

"We don’t want a Heath Robinson wire springs affair on somebody’s head.

"It needs to look sophisticated and appropriate, probably less like a prosthetic and more like a cool Bluetooth device."

The first implant is scheduled to go ahead next year which is expected to be followed by clinical trials, research and user feedback to the team.

The development of a bionic eye was one of the key aspirations out of the 2020 summit that was held in 2008.

Professor Armstrong says it is “amazing” that a prototype for the technology has already been achieved.

"To be honest when I heard about that 2020 conference and all of the people there, I thought it was a little bit of a hot air fest if you know what I mean," he said.

"But I’ve been proven completely wrong.

"Some of the initiatives from that, this is a major one for sure, have been brought to fruition and it’s wonderful for Australia and equally wonderful for Monash University."

Bionic eye maker has vision of the future

Robert Greenberg got tired of hearing from senior engineers that it wasn’t possible to build his product idea: a bionic eye that gives sight to the blind.

"A lot of the folks straight out of school didn’t know any better, so I hired them instead," quipped Greenberg, chief executive of Second Sight Medical Products Inc., a Sylmar biotech company. "They didn’t know how hard it was going to be, that it was impossible. And so they tried."

Greenberg can laugh now that he once thought developing the device would take a year and $1 million. Some 20 years and $200 million later, the first bionic eye has helped more than 20 European patients regain some of their sight.

Called the Argus II Retinal Prosthesis System, the device recently was approved by the Food and Drug Administration. Second Sight, which has 100 employees, is allowed to sell the bionic eye system to patients in the U.S. with advanced retinitis pigmentosa, a degenerative eye disease that can cause blindness.

"We are a far cry from restoring 20/20 vision," said Brian V. Mech, Second Sight’s vice president of business development, who holds a doctorate in materials science and an MBA from the UCLA Anderson School of Management.

"We are taking blind people back up to low vision, and that is pretty significant."

Mech likes to show videos of once-sightless patients who, after receiving the retinal prosthesis, are able to follow a person walking down the street and discern a street curb without using their canes.

"Until our product, these patients had no other option to obtain the ability to see," Mech said of the $100,000 device, part of which rests on a pair of Oakley Inc. sunglass frames. The cost to European patients has been paid by insurance companies in most cases.

Palo Alto attorney Dean Lloyd, who lost his vision 17 years ago, got the bionic eye system as part of the U.S. testing process. It allows him to see “boundaries and borders, not images” but has had a profound effect on his life.

Lloyd cites an incident before he received the eye system that still rankles. In the middle of a courtroom trial, an opposing attorney said Lloyd didn’t stand a chance with his case because he couldn’t even keep his socks straight: Lloyd had mixed up his black, courtroom socks with his white athletic ones.

"What did I do after the surgical procedure that I hadn’t been able to do?" Lloyd said. "I went home and sorted all of my socks."

The story of how the bionic eye came to be made in Sylmar underscores the state’s long record of medical device advances and involves top university researchers who were brought to Southern California to work on the project.

Greenberg likened the degree of difficulty to “shrinking a television set to the size of a pea, then throwing it into the ocean and expecting it to work.”

For Greenberg, it began in the early 1990s when he was a doctoral candidate in the Department of Biomedical Engineering at Johns Hopkins University in Baltimore.

Some of the first work was being done there, testing patients who had lost their vision because of retinitis pigmentosa, to see if electrically stimulating their retinas would produce results. It did.

"Using one electrode, the patient saw one spot of light," Greenberg said. "Second electrode, and the patient was seeing two spots of light. During that experiment, I was hooked."

Greenberg said he thought: “This is just engineering. Put more spots and you could make more pixels, like lights on a scoreboard or pixels on your computer monitor. You could see images.”

There was a breakthrough of another sort a few years later, in Washington. There, Greenberg was working as a medical officer and a lead reviewer for the FDA’s Office of Device Evaluation when he met entrepreneur Alfred E. Mann.

Mann had already established himself as a medical device developer through Mannkind Corp. and several other Southern California companies. During the 1980s, the self-made billionaire founded Pacesetter Systems, which made cardiac pacemakers. From there, he moved on to insulin pumps and related equipment.

Another Mann-funded company, Advanced Bionics Corp., took on cochlear implants, which could restore hearing to the deaf. It was the electrode-based cochlear implant that formed the rough basis of Second Sight’s first bionic eye.

In 1998, Second Sight opened with the financial backing of Mann and Sam Williams, another successful entrepreneur whose company, Williams International, designed and built small, efficient turbofan jet engines.

"Sam Williams was blind from retinitis pigmentosa, the disease that we are treating," Mech said. "He had invested along with Al in Advanced Bionics, which restores hearing for deaf people, and they were already on the market in the ’90s. Sam said to Al, ‘Why can’t we do the same for blind people?’"

How Neuroscience Will Fight Five Age-Old Afflictions

SEIZURES

A device delivers targeted drugs to calm overactive neurons

For years, large clinical trials have treated people with epilepsy using so-called deep-brain stimulation: surgically implanted electrodes that can detect a seizure and stop it with an electrical jolt. The technology leads to a 69 percent reduction in seizures after five years, according to the latest results.

Tracy Cui, a biomedical engineer at the University of Pittsburgh, hopes to improve upon that statistic. Her group has designed an electrode that would deliver both an electrical pulse and antiseizure medication. “We know where we want to apply the drug,” Cui says, “so you would not need a lot of it.”

To build the device, Cui’s team immersed a metal electrode in a solution containing two key ingredients: a molecule called a monomer and the drug CNQX. Zapping the solution with electricity causes the monomers to link together and form a long chain called a polymer. Because the polymer is positively charged, it attracts the negatively charged CNQX, leaving the engineers with their target product: an electrode coated in a film that’s infused with the drug.

The researchers then placed the electrodes in a petri dish with rat neurons. Another zap of electricity disrupted the electrostatic attraction in the film, causing the polymer to release its pharmacological payload—and nearby cells to quiet their erratic firing patterns. Cui says her team has successfully repeated the experiment in living rats. Next, she’d like to test the electrodes in epileptic rats and then begin the long process of regulatory approval for human use.

The body’s blood-brain barrier protects the organ from everything but the smallest molecules, rendering most drugs ineffective. As a result, this drug-​delivery mechanism could treat other brain disorders, Cui says. The electrodes can be loaded with any kind of small drug—like dopamine or painkillers—making it useful for treating Parkinson’s disease, chronic pain, or even drug addiction.

DEMENTIA

Electrode arrays stimulate mental processing

Dementia is one of the most well-known and frustrating brain afflictions. It damages many of the fundamental cognitive functions that make us human: working memory, decision-making, language, and logical reasoning. Alzheimer’s, Huntington’s, and Parkinson’s diseases all lead to dementia, and it’s also sometimes associated with multiple sclerosis, AIDS, and the normal process of aging.

Theodore Berger, a biomedical engineer at the University of Southern California, hopes to help people stave off the symptoms of dementia with a device implanted in the brain’s prefrontal cortex, a region crucial for sophisticated cognition. He and colleagues at Wake Forest Baptist Medical Center tested the device in a study involving five monkeys and a memory game.

First the team implanted an electrode array so that it could record from layers 2/3 and 5 of the prefrontal cortex and stimulate layer 5. The neural signals that jet back and forth between these areas relate to attention and decision-making. The team then trained the monkeys to play a computer game in which they saw a cartoon picture—such as a truck, lion, or paint palette—and had to select the same image from a panel of pictures 90 seconds later.

The scientists initially analyzed the electrical signals sent between the two cortical layers when the monkeys made a correct match. In later experiments, the team caused the array to emit the same signal just before the monkey made its decision. The animals’ accuracy improved by about 10 percent. That effect may be even more profound in an impaired brain. When the monkeys played the same game after receiving a hit of cocaine, their performance dropped by about 20 percent. But electrical stimulation restored their accuracy to normal levels.

Dementia involves far more complicated circuitry than these two layers of the brain. But once scientists better understand exactly how dementia works, it may be possible to combine several implants to each target a specific region.

BLINDNESS

Gene therapy converts cells into photoreceptors, restoring eyesight

Millions of people lose their eyesight when disease damages the photoreceptor cells in their retinas. These cells, called rods and cones, play a pivotal role in vision: They convert incoming light into electrical impulses that the brain interprets as an image.

In recent years, a handful of companies have developed electrode-array implants that bypass the damaged cells. A microprocessor translates information from a video camera into electric pulses that stimulate the retina; as a result, blind subjects in clinical trials have been able to distinguish objects and even read very large type. But the implanted arrays have one big drawback: They stimulate only a small number of retinal cells—about 60 out of 100,000—which ultimately limits a person’s visual resolution.

A gene therapy being developed by Michigan-based RetroSense could replace thousands of damaged retinal cells. The company’s technology targets the layer of the retina containing ganglion cells. Normally, ganglion cells transmit the electric signal from the rods and cones to the brain. But RetroSense inserts a gene that makes the ganglion cells sensitive to light; they take over the job of the photoreceptors. So far, scientists have successfully tested the technology on rodents and monkeys. In rat studies, the gene therapy allowed the animals to see well enough to detect the edge of a platform as they neared it.

The company plans to launch the first clinical trial of the technology next year, with nine subjects blinded by a disease called retinitis pigmentosa. Unlike the surgeries to implant electrode arrays, the procedure to inject gene therapy will take just minutes and requires only local anesthesia. “The visual signal that comes from the ganglion cells may not be encoded in exactly the fashion that they’re used to,” says Peter Francis, chief medical officer of RetroSense. “But what is likely to happen is that their brain is going to adapt.”

PARALYSIS

A brain-machine interface controls limbs while sensing what they touch

Last year, clinical trials involving brain implants gave great hope to people with severe spinal cord injuries. Two paralyzed subjects imagined picking up a cup of coffee. Electrode arrays decoded those neural instructions in real time and sent them to a robotic arm, which brought the coffee to their lips.

But to move limbs with any real precision, the brain also requires tactile feedback. Miguel Nicolelis, a biomedical engineer at Duke University, has now demonstrated that brain-machine interfaces can simultaneously control motion and relay a sense of touch—at least in virtual reality.

For the experiment, Nicolelis’s team inserted electrodes in two brain areas in monkeys: the motor cortex, which controls movement, and the nearby somatosensory cortex, which interprets touch signals from the outside world. Then the monkeys played a computer game in which they controlled a virtual arm—first by using a joystick and eventually by simply imagining the movement. The arm could touch three identical-looking gray circles. But each circle had a different virtual “texture” that sent a distinct electrical pattern to the monkeys’ somatosensory cortex. The monkeys learned to select the texture that produced a treat, proving that the implant was both sending and receiving neural messages.

This year, a study in Brazil will test the ability of 10 to 20 patients with spinal cord injuries to control an exoskeleton using the implant. Nicolelis, an ardent fan of Brazilian soccer, has set a strict timetable for his team: A nonprofit consortium he created, the Walk Again Project, plans to outfit a paraplegic man with a robotic exoskeleton and take him to the 2014 World Cup in São Paulo, where he will deliver the opening kick.

DEAFNESS

Stem cells repair a damaged auditory nerve, improving hearing

Over the past 25 years, more than 30,000 people with hearing loss have received an electronic implant that replaces the cochlea, the snail-shaped organ in the inner ear whose cells transform sound waves into electrical signals. The device acts as a microphone, picking up sounds from the environment and transmitting them to the auditory nerve, which carries them on to the brain.

But a cochlear implant won’t help the 10 percent of people whose profound hearing loss is caused by damage to the auditory nerve. Fortunately for this group, a team of British scientists has found a way to restore that nerve using stem cells.

The researchers exposed human embryonic stem cells to growth factors, substances that cause them to differentiate into the precursors of auditory neurons. Then they injected some 50,000 of these cells into the cochleas of gerbils whose auditory nerves had been damaged. (Gerbils are often used as models of deafness because their range of hearing is similar to that of people.) Three months after the transplant, about one third of the original number of auditory neurons had been restored; some appeared to form projections that connected to the brain stem. The animals’ hearing improved, on average, by 46 percent.

It will be years before the technique is tested in humans. Once it is, researchers say, it has the potential to help not only those with nerve damage but also people with more widespread impairment whose auditory nerve must be repaired in order to receive a cochlear implant.

Altering eye cells may one day restore vision

Doctors may one day treat some forms of blindness by altering the genetic program of the light-sensing cells of the eye, according to scientists at Washington University School of Medicine in St. Louis.

Working in mice with retinitis pigmentosa, a disease that causes gradual blindness, the researchers reprogrammed the cells in the eye that enable night vision. The change made the cells more similar to other cells that provide sight during daylight hours and prevented degeneration of the retina, the light-sensing structure in the back of the eye. The scientists now are conducting additional tests to confirm that the mice can still see.

“We think it may be significantly easier to preserve vision by modifying existing cells in the eye than it would be to introduce new stem cells,” says senior author Joseph Corbo, MD, PhD, assistant professor of pathology and immunology. “A diseased retina is not a hospitable environment for transplanting stem cells.”

The study is available in the early online edition of Proceedings of the National Academy of Sciences.

Mutations in more than 200 genes have been linked to various forms of blindness. Efforts are underway to develop gene therapies for some of these conditions.

Rather than seek treatments tailored to individual mutations, Corbo hopes to develop therapies that can alleviate many forms of visual impairment. To make that possible, he studies the genetic factors that allow cells in the developing eye to take on the specialized roles necessary for vision.

Study of how eye cells become damaged could help prevent blindness

Light-sensing cells in the eye rely on their outer segment to convert light into neural signals that allow us to see. But because of its unique cylindrical shape, the outer segment is prone to breakage, which can cause blindness in humans. A study published by Cell Press on January 22nd in the Biophysical Journal provides new insight into the mechanical properties that cause the outer segment to snap under pressure. The new experimental and theoretical findings help to explain the origin of severe eye diseases and could lead to new ways of preventing blindness.

"To our knowledge, this is the first theory that explains how the structural rigidity of the outer segment can make it prone to damage," says senior study author Aphrodite Ahmadi of the State University of New York Cortland. "Our theory represents a significant advance in our understanding of retinal degenerative diseases."

The outer segment of photoreceptors consists of discs packed with a light-sensitive protein called rhodopsin. Discs made at nighttime are different from those produced during the day, generating a banding pattern that was first observed in frogs but is common across species. Mutations that affect photoreceptors often destabilize the outer segment and may damage its discs, leading to cell death, retinal degeneration, and blindness in humans. But until now, it was unclear which structural properties of the outer segment determine its susceptibility to damage.

To address this question, Ahmadi and her team examined tadpole photoreceptors under the microscope while subjecting them to fluid forces. They found that high-density bands packed with a high concentration of rhodopsin were very rigid, which made them more susceptible to breakage than low-density bands consisting of less rhodopsin. Their model confirmed their experimental results and revealed factors that determine the critical force needed to break the outer segment.

The findings support the idea that mutations causing rhodopsin to aggregate can destabilize the outer segment, eventually causing blindness. “Further refinement of the model could lead to novel ways to stabilize the outer segment and could delay the onset of blindness,” says Ahmadi.

AR Goggles Restore Depth Perception To People Blind in One Eye

People who’ve lost sight in one eye can still see with the other, but they lack binocular depth perception.

Some of them could benefit from a pair of augmented reality glasses being built at the University of Yamanashi in Japan, that artificially introduces a feeling of depth in a person’s healthy eye.

The group, led by Xiaoyang Mao, started out with a pair of commercially available 3D glasses, the daintily named Wrap 920AR, manufactured by Vuzix Corporation. (Vuzix is also building another AR headset called the M100 that on first sight looks like quite the competitor to to Google Glass.)

The Wrap 920AR looks like a pair of regular tinted glasses, but with small cameras poking out of each lens. The lenses are transparent and the device, Vuzix explains on its website, both captures and projects images, giving the wearer of the device front-row seats to a 2D or 3D AR show transmitted from a computer.

The group at Yamanashi have created software that makes use of the twin cameras. When a person puts the glasses on, each camera scopes out the scene that each eye would see. The images are funneled into software on a computer, which combines the perspective of both cameras and creates a “defocus” effect. That is, some objects to stay in focus while others stay out of focus, resulting in a feeling of depth. That version of the scene in front of them is projected to the single healthy eye of the wearer.

The system isn’t quite ready to be taken for spin around town yet. It’s bulky still, the creators write, and needs a computer by its side, creating and projecting images in real time. But the creators admit such computing power is likely to be found on mobile devices soon, and when it is, they’ll be ready.

New technique to deliver stem cell therapy may help damaged eyes regain their sight

Engineers at the University of Sheffield have developed a new technique for delivering stem cell therapy to the eye which they hope will help the natural repair of eyes damaged by accident or disease. This could help millions of people across the world retain – or even regain - their sight.

In research published in the journal Acta Biomaterialia, the team describe a new method for producing membranes to help in the grafting of stem cells onto the eye, mimicking structural features of the eye itself. The technology has been designed to treat damage to the cornea, the transparent layer on the front of the eye, which is one of the major causes of blindness in the world.

Using a combination of techniques known as microstereolithography and electrospinning, the researchers are able to make a disc of biodegradable material which can be fixed over the cornea. The disc is loaded with stem cells which then multiply, allowing the body to heal the eye naturally.

“The disc has an outer ring containing pockets into which stem cells taken from the patient’s healthy eye can be placed,” explains EPSRC Fellow, Dr Ílida Ortega Asencio, from Sheffield’s Faculty of Engineering. “The material across the centre of the disc is thinner than the ring, so it will biodegrade more quickly allowing the stem cells to proliferate across the surface of the eye to repair the cornea.”

A key feature of the disc is that it contains niches or pockets to house and protect the stem cells, mirroring niches found around the rim of a healthy cornea. Standard treatments for corneal blindness are corneal transplants or grafting stem cells onto the eye using donor human amniotic membrane as a temporary carrier to deliver these cells to the eye. For some patients, the treatment can fail after a few years as the repaired eyes do not retain these stem cells, which are required to carry out on-going repair of the cornea. Without this constant repair, thick white scar tissue forms across the cornea causing partial or complete sight loss. The researchers have designed the small pockets they have built into the membrane to help cells to group together and act as a useful reservoir of daughter cells so that a healthy population of stem cells can be retained in the eye.

Smart specs may replace guide dogs

Smart specs for the blind that could take the place of white canes and guide dogs may be available in two years, researchers have said.

The hi-tech glasses are designed to prevent “legally blind” individuals with a small degree of residual vision from bumping into objects.

They use tiny stereo cameras in the frames to project simplified images onto the lenses which become brighter the closer an object is.

From January next year the glasses will be tested in a series of trials involving 160 people with severely impaired sight in Oxford and London. Developer Dr Stephen Hicks, from Oxford University, said he hoped a finished model will be commercially available in around two years.

The cost is expected to be around £600 - slightly more than a smart phone. In comparison, a guide dog costs up to £30,000 to train.

Dr Hicks said the spectacles were designed as a navigational aid, not to restore lost vision.

"The glasses work using a pair of cameras that determine the distance of objects and we simply translate that into a light display," he said. "This is not restoring sight, but we can improve spatial awareness."

Around 300,000 people in the UK are registered as legally blind. Of these, 90% possess some residual vision allowing them to detect blurry shapes and differences between light and dark.

"The aim is to increase the independence of the hundreds of thousands of people who are visually impaired in the UK," said Dr Hicks.

The research was funded through the National Institute for Health Research Invention for Innovation (i4i) programme.