Building a bionic eye
Kate Fox describes how strokes of luck – both good and bad – led her to work on an interdisciplinary "bionic eye" project aimed at helping people with retinal disease.
As an undergraduate studying biomedical engineering in the mid-1990s, I really did not consider where my degree could lead. As far as I knew, my only option was to become a technician in a hospital and work on equipment that went "beep" and "ping". It was not until after a lucky PhD, a life-changing event and a quickly regretted career change that it became apparent that my skills could make a difference in another area altogether: the physics and materials science of artificial vision.
Artificial vision uses an artificial input to replicate the biological pathways used in "normal" vision. I work as part of a multi-institutional collaboration called Bionic Vision Australia that is developing technology that aims to stimulate vision for people who lose visual acuity as a result of retinal disease. The technology consists of a camera attached to a pair of glasses that captures an image and transmits information via radio-frequency signals to a microchip implanted in the eye. In order to translate the signal to the retina, micro-electrodes are attached to the chip, and these stimulate the remaining retinal cells connecting to the optic nerve. The stimulated cells then send signals along the "normal" biological pathway to the brain, such that the brain can form an image. In order for all of this to work, it is essential that the materials used in the implant are biocompatible – and this is where my materials-science skills are applicable.
The role of luck
The story of how I came to work on the project is full of luck, both good and bad. Early on in my student career, it became clear that I was not interested in building electrical circuits, writing complicated computer programs or working on complex mathematical algorithms. I discovered that I was much more suited to the physics aspects of my subject, such as the properties of materials and ways of using them to build devices. Fortunately, Flinders University (where I did my undergraduate degree) did not restrict me to working on strictly biomedical projects, so I was able to expand my skills by trekking off to the world of defence science, conducting an honours project that involved designing and building antennas for electronic warfare.
This turned out to be a stroke of good luck, although I did not realize it at the time. In fact, I chose the project simply because it sounded fun and it took me away from the standard world of biomedical-engineering projects, where my classmates would (year after year) build a robot baby or devices to detect the human body's electrical signals. The antenna task taught me some important lessons about the discipline required for driving your own project, particularly where the entire outcome and success is based solely on your input. It also showed me that I could succeed in areas of technology that I had never learned in my university degree. More importantly, it proved that computer programming and theory-based work was not where I wanted to go with my career; I found that the practical need to build the antenna was the more desirable aspect of the project.
Still, at the end of the year I was no closer to knowing where I wanted to take my degree. But I knew clearly what I did not want to do: studying for five years to become a technician in a hospital was not particularly appealing to my ego, and a six-month placement during my degree had shown me that fixing hospital equipment was not going to satisfy my intellectual needs anyway. So instead, I jumped into a PhD, where again, I selected my research project – developing coatings for hip implants – because it sounded fun.
Towards the end of my PhD I experienced another stroke of good luck: I had a child. As any new parent will concur, your first child is immediately perfect and, accordingly, my son was adorable. But as happy as that day was, the following night was truly horrid: we learned that our son had had an intracranial haemorrhage, and he needed to have brain surgery. To this day, the only reason we know of for his haemorrhage is bad luck, but its effects were serious. Within weeks of his birth and after a series of brain surgeries, we learned that his vision was impaired.
As you would expect, this was devastating news. Not knowing the extent, if any, of your child's vision is a terrifying experience. In order to deal with it more effectively, I quickly finished my thesis, and soon afterwards someone suggested that I should consider a role as a patent attorney. At the time, the rationale for a career change seemed sound: working in the private sector was stable and removed me from the cyclic nature of research funding. Upon reflection, however, it was probably a job I chose for my family rather than myself. Working as a patent attorney never truly suited my personality. Although I was drawn to the adventurous nature of invention and discovery, I found the reality of sitting in my office debating the choice of words frustrating. More importantly, the culture of six-minute billing cycles never sat well with me.
A new vision
As I was considering other career options, I noticed an advertisement for researchers to join the recently established "bionic eye" project at Bionic Vision Australia. This project brings together experts from institutions across Australia, including the University of Melbourne, University of New South Wales, NICTA, the Center for Eye Research Australia and the Bionics Institute. As such, the team assembled consists of experts in the fields of ophthalmology, biomedical engineering, electrical engineering, materials science, neuroscience, vision science, psychophysics (the relationship between a physical stimulus and the sensation/percept received), and wireless integrated-circuit design, as well as surgical, preclinical and clinical practice.
The project involves designing and implementing two retinal prostheses: a wide-view device, with 100 electrodes positioned between the choroid and the sclera layers of the eye; and a high-acuity device, positioned within the ocular chamber and comprising more than 1000 diamond electrodes. The wide-view prototype aims to restore some sense of vision to assist patients with mobility and independence, while the high-acuity device will hopefully give recipients a greater sense of visual detail. The use of diamond electrodes makes the technology new and exciting. Diamond is well known as a hard material, and it is attractive for biomedical applications because it is chemically inert, biocompatible and thermally conductive. More usefully for our applications in neural stimulation, diamond can be selectively doped to become electrically conducting and able to deliver current to retinal tissue.
Variety, the spice of life
I now work as part of the high-acuity electrode team, which is located within the Melbourne Materials Institute and co-located in the School of Physics at the University of Melbourne. The University of Melbourne and, in particular, our project leader Steven Prawer, is world renowned in diamond research, so we are responsible for the design and fabrication of the diamond electrode array. The team is truly interdisciplinary, but the participants all work under the common umbrella of materials science. In order to make the electrodes, we use a variety of microfabrication techniques such as substrate masking, diamond deposition and post-fabrication laser technologies.
My role is to integrate this technology with other research activities across Bionic Vision Australia. As such, my job is quite varied. On any given day, I might be helping with electrode fabrication or performing electrical testing or in vitro experiments. Alternatively, I could be meeting with our stakeholders such as the Bionic Vision Australia executive, surgeons or device-development team to provide feedback on requested design changes, or even drawing on my previous career to provide intellectual-property advice.
Although this particular technology would not be able to address my son's condition, my experience with his visual impairment has helped me to understand and appreciate the impact that this project may have on the vision-impaired community. Many people who are living with common eye disorders such as retinitis pigmentosa and age-related macular degeneration will potentially benefit from the bionic eye, and it is a fantastic and humbling experience to be part of a project of this kind. The prospect of other parents benefiting from my work inspires me to make this project a success and luckily I have the materials-science knowledge to be part of it.
Kate Fox is a research fellow in the Bionic Eye project at the University of Melbourne, Australia, e-mail firstname.lastname@example.org
This article appears in the December 2011 issue of Physics World.
last edited: August 06, 2012