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Saturday / April 13.
HomemistoryAustralian Bionic Eye Takes Global Lead

Australian Bionic Eye Takes Global Lead

A ground-breaking bionic eye that could provide vision to people with optic nerve damage is expected to be trialed in Australia next year. Called the ‘Gennaris’ the device will enable people – even those who do not have eyeballs – to recognise the presence of different objects and other people.

The Gennaris has been developed by the Monash Vision Group (MVG), a consortium of engineers, physiologists and neuroscientists at Monash University, doctors at The Alfred Hospital and Victorian companies MiniFAB and Grey Innovation.

This futuristic looking bionic eye has been created for people with vision impairment caused by a number of conditions, including glaucoma. It may also help those who have damage to their optic nerves or eyes resulting from trauma or disease.

The Gannaris will give vision impaired people sight with the aid of a brain implant that connects wirelessly to a processor and a camera, which can be housed in a pair of glasses or other custom-designed headwear.

That tiny camera captures images and draws out the most useful information… like a clear pathway…

That tiny camera captures images and draws out the most useful information… like a clear pathway, the edge of an object or the presence of a person, then sends the information, via a digital processor to a chip implanted under the skull at the back of the patient’s head. This chip stimulates the visual cortex via electrodes, and in doing so, produces flashes of light that the brain interprets as images.

The technology allows blind people to ‘see’ objects as a series of dots or shapes. Additionally, facial recognition software lets the user identify the presence of people while other bespoke software can allow them to recognise and negotiate stairs.

First tests with patients are expected to begin next year and if they are successful, researchers at Monash believe that by 2022, the technology could become widely used.

“We aim to implant a series of tiles, each with 43 electrodes, into the patient. The number of tiles we implant will be dependent on each person and how large and accessible their primary visual cortex is – but we’re aiming to implant between 4-11 tiles. This will produce a few hundred spots of light, or phosphenes, in the user’s visual field,” said Dr. Jeanette Pritchard, General Manager of MVG.

She said first patients are likely to be people who previously had full adult vision because their brains are hardwired to understand the kind of signals that the device will provide. People who have some residual sight will not be able to participate in first trials because it’s unlikely that the vision the implant will give at this stage would provide any further improvement.

Professor Arthur Lowery, Director of Monash Vision Group, said the sight provided would be similar to an advanced type of radar. People with the implant will be able to recognise different objects, and (for example) go into a meeting and recognise how many people are there. Additionally, he said, with the ability to see objects like trees and paths, they will be able to venture outside.

Unlike other retinally implanted bionic eyes being developed in Australia, the United States and Germany, the Gennaris does not rely on the optic nerve being viable, which makes it suitable for people who have lost their sight from a large number of conditions or traumatic injury.

“You don’t need eyeballs for this. If you have optic nerve damage or glaucoma this can work as it bypasses many parts of the human visual pathway. It gives hope to people who have suffered serious damage to their eyes,” said Professor Lowery.

Bionic Vision Australia

Last year Bionic Vision Australia (BVA) successfully implanted prototype bionic eye devices in three patients. BVA is a consortium that includes the Bionics Institute, the Centre for Eye Research Australia, the National Vision Research Institute, the Royal Victorian Eye and Ear Hospital, technology research group NICTA, and the universities of Melbourne, NSW and Western Sydney.

Unlike the Monash Vision Group system, BVA’s retinal implant requires a patient to have a functional visual pathway from the retina to the brain along the optic nerve, as well as some intact inner retinal cells (particularly the ganglion cells). As such, the technology aims to address retinitis pigmentosa and age-related macular degeneration.

BVA’s vision system will consist of a camera, attached to a pair of glasses, which transmits electrical stimulation to a microchip implanted in the retina. Dr. Penny Allen is a vitreoretinal surgeon at the Royal Victorian Eye and Ear Hospital in Melbourne and leads the surgical team for Bionic Vision Australia. She explains that the prototype is approximately 8mm x 16mm, is made of a silicon sheet with electrodes embedded within and sits in the suprachoroidal space – a pocket between the outside white layer of the eye (sclera) and the choroid.

Electrodes on the implanted chip convert signals into electrical impulses to stimulate cells in the retina that connect to the optic nerve. These impulses are then passed down along the optic nerve to the vision processing centres of the brain, where they are interpreted as an image.

The prototype currently being tested by BVA has a small lead wire that extends from the back of the eye to an external connector behind the ear. This system is connected to a unit in the laboratory, which allows researchers to stimulate the implant in a controlled manner to study what patients are perceiving.

Understanding the Brain’s Interpretation

Testing with the device is helping researchers at BVA learn more about how the brain interprets visual information provided by the implant.

“Every week, each of the patients spends a full day in the laboratory with our researchers,” said Veronika Gouskova at Bionic Vision Australia. “We connect their implant to a unit in the laboratory and begin the testing by sending stimulus – effectively electrical pulses – to an electrode or a to a group of electrodes in the implant.” She said this has been happening with each of the patients since their implants were ‘switched on’ 12 months ago.

The aim of the process is to complete a phosphene map by matching each stimulus or pulse sent to the electrode with what pattern the patient sees. Each patient is likely to perceive different shapes from the same stimulus.

To gather the mapping information the patients verbally describe what they’re seeing when a stimulus is triggered. Additionally the tracking devices monitor their gaze to detect where the patient is seeing the pattern in space. A tracker on the patient’s index finger enables the patient to draw in space what they’re seeing, as and where the shapes appear.

Once a phosphene map has been completed for each person, the BVA’s researchers will use that information to preset more complex shapes, like letters and numbers. Then they will conduct testing to find out whether the patients can recognise them.

The next stage of the process will be to connect each patient’s implant to a camera rather than the computer being used in the laboratory. This will enable the team to expand the research by taking the patient out of the lab, and ultimately outside where the electrodes will be stimulated by images captured on a video camera.

Bionic Vision Australia is currently building a portable version of the laboratory system that will control each patient’s implant when they make the move to go outside the lab.

“It’s a small system the patients will be able to carry with them, that has a video camera inbuilt. The camera will capture the visual scene then send the stimulus to the implant, similar to what we’ve been doing in the lab,” said Ms. Gouskova.

Eventually the camera will sit on a pair of glasses and the patient will carry a portable system – the size of a mobile phone, or even smaller – with them to control the process of sending stimuli to the electrodes.

Alpha IMS

In Germany, researchers behind the Alpha IMS retinal prosthesis claim their subretinal bionic eye is streets ahead of existing implanted bionic devices, because in the first round of clinical trials eight out of nine patients reported being able to detect mouth shapes (smiles, frowns), small objects such as telephones and cutlery, signs on doors, and even determine whether a glass of wine is red or white.

Like BVA’s prototype bionic eye, the Alpha IMS, developed at the University of Tübingen in Germany, requires the patient’s optic nerve to be intact. However where it differs is that the Alpha IMS is completely self-contained, with a built-in sensor that works with photodiodes to directly gather its imagery from the light that passes into the patient’s eye. In effect, light falls through the eye as it does with healthy vision, and onto the photodiode where it is converted into an electrical signal and passed to the nerve cell. No external camera or data processor is required.

As a result of this innovation, the Alpha IMS allows the patient to look from side to side by simply swivelling the eyeballs normally, whereas a patient fitted with the Argus II, an implant recently approved by the Federal Drugs Administration for public use in America, must physically turn their head to achieve the same vision.

Argus II

Like the Alpha IMS and BVA’s bionic eye, the Argus II relies on the patient’s optic nerve being intact.

The Argus II System converts video images captured by a miniature camera housed in the patient’s glasses into a series of small electrical pulses that are transmitted wirelessly to an array of electrodes that are placed epiretinally on the surface of the retina. These pulses aim to stimulate the retina’s remaining cells, and in doing so, create the perception of patterns of light in the brain. The patient learns to interpret these visual patterns and as a result, regains some visual function.

According to a paper published in the British Journal of Ophthalmology, some of the blind subjects fitted with the Argus II were able to consistently identify letters and words using the retinal implant, indicating reproducible spatial resolution. This, in combination with stable, long-term function of the device, represents significant progress in the evolution of artificial sight.

“These lasting results are very exciting, and add to the ever increasing data supporting the benefit of the Argus II,” noted Robert Greenberg, MD PHD, President and CEO of Second Sight Medical Products. “We have people approaching six years of use with Argus II. The long-term benefit is one of several features that differentiate the Argus II from other efforts around the world and was a significant factor in gaining
FDA approval.”

Study results showed that the percentage correct letter identification for the 21 subjects tested was: 72.3 per cent with system on and 17.7 per cent with system off. A subgroup of six subjects was able to consistently read letters of reduced size, the smallest measuring 0.9 cm (1.7°) at 30 cm. A further group of four subjects correctly read two-, three- and four-letter words with 75 per cent accuracy (two letter words) – 58 per cent accuracy (four letter words). Control data confirmed that subjects could not achieve these tasks if the system was disabled, or if the spatial resolution provided by the eye chip was artificially scrambled.
This data shows that reading is possible for the best performers using Argus II. Average use duration was 19.9 months at the time of this study.

“The fact that we are seeing many of our patients being able to recognise large letters, locate the position of objects and more, is truly encouraging and beyond initial expectations,” noted lead study author Lyndon da Cruz, MD, consultant retinal surgeon at Moorfields Eye Hospital, London.

Bionic Contact Lens

Researchers at Bar-Ilan University in Israel recently released details of a bionic contact lens at prototype stage, which ‘presses’ images onto the surface of the eye to help the brain decipher through touch what the wearer is looking at. The lens, invented by Prof. Zeev Zalevsky, works in much the same way as Braille allows people who are blind to ‘see’ the written word.

Prototypes tested on healthy people indicate that the non-invasive device is quick to come to terms with. After a few minutes of learning how to associate actual images with the sensations they felt on their fingertips, people who participated in the trial could actually ‘see’ using the bionic contact lens.

According to reports, the lens uses electrical signals sent to it from a small transponder, clipped to a pair of glasses or downloaded to a smartphone. A regular off-the-shelf camera, like one housed inside a smartphone, ‘looks’ at the surrounding environment – a pedestrian crossing, items for sale in a shop, or a family member for instance – then transmits the encoded image via the lens to the wearer’s cornea. The image gets translated into a tactile sensation that can be interpreted visually.

“The cornea has the highest density of tactile sensors in the human body,” Prof. Zalevsky from Bar-Ilan University reported.

“There are 600 times more sensors in your cornea than on fingertips which are used to touch and read Braille. And since there are so many tactile sensors in the eyes, one can actually sense and ‘feel’ an image at a very high resolution, helping you really see with your eyes when you are blind,” he says.

Prof. Zalevsky says the sensation is similar to feeling a person’s face with your hands to understand how they look. “We can do the same by touching projected images from the camera onto the cornea of your eye.”

Going Forward

While the Argus II has already been approved for commercial sale in America with its 60 electrodes, researchers at BVA are working on developing a 256-electrode model, which will eventually have the capacity to be developed into a device with 1024 electrodes.

With so many stimulating electrodes packed into such a tiny space, the opportunity is there to achieve far greater detail and even further enhanced visual acuity – indeed, the aim of this device is to enable patients to read large print and recognise faces.

The BVA’s implant will be developed for longevity. “We’re using diamond materials to form the electrode array and to seal this implant. Diamond is very biocompatible because it is basically carbon. This means the implant will be safe to stay in the body for the lifetime of the patient,” said Ms. Gouskova.

Additionally, its capacity to process data will be upgradeable, much like the software of a computer. “The great thing about developing a bionic eye with an external data processor is that over time as the way we are able to deliver data to the patient’s implant improves, we can easily upgrade each patient’s system with no need for surgery – it will be as simple as a software upgrade,” she explained.

Collaboration Working Well

With complimentery technologies on the go, Bionic Vision Australia and Monash Vision Group collaborate whenever possible.

“This is really important technology and we’re working with Bionic Vision Australia to develop our expertise and together build devices that will address a large range of blinding diseases,” said Dr. Pritchard from Monash University. “There’s so much expertise that goes into a development like this – so many disciplines need to be involved. It’s quite incredible that we’re doing this here in Australia,” she said.

“We often attend roadshows together, present our research to key stakeholders such as the vision impaired community, and pass enquiries from the public to each other for response. Our researchers and Board Chairs frequently exchange relevant information and recently we worked together to successfully secure future funding for our projects going forward,” said Ms. Gouskova.

“We’re also working on many other avenues to take these projects forward,” said Dr. Pritchard from Monash University. “For example, we have worked together on grant applications to fund specific aspects of the program beyond this phase.”

She said the response the two groups receive from community groups is encouraging. “We have such a lot of interaction with members of the vision-impaired community that really highlights how important each of these projects are. If you can’t secure funding for projects like this, then that’s a real shame,” she said.