Get your geek on
June 2012
An eye on the future of circuit design
The circuit design industry in Australia may still be young, but a team of electronic engineers in Melbourne are catching up, building a microchip for an unexpected purpose: to drive a bionic eye.
While the device itself may be small, experts from a range of fields are involved to ensure it is safe and effective, before it can be implanted in patients. The microchip is the engine which drives the device, and with so many design possibilities and iterations, it can take some time to get the specs just right.
I caught up with electronic engineers, Jeff and Nhan at NICTA’s Victorian Research Laboratory to find out more…
Before I sit down Jeff clears my seat of the tangle of wires and electronic scraps sitting on top. Their office looks like any other, except for the whiteboard behind me covered in equations, which look much more complicated than the ones I remember from high school (or even uni, for that matter). Jeff’s role with Bionic Vision Australia is to build the receiver and transmitter for the microchip, while Nhan is designing the stimulator for the chip.
Can you explain how the bionic eye works?
Jeff: It mimics the natural process of the way we see things. The camera, which sits on a pair of glasses, captures the image, processes it and sends the data to the internal unit. The microchip decodes the data and uses it to generate stimulation waveforms, which will stimulate the electrode array. The array is attached to the retina, so it stimulates the cells, and the signal travels through the optic nerve to the vision processing centres of the brain.
That’s pretty impressive. What’s the coolest thing about your job?
Jeff: I love the creativity of it; it’s actually very creative work. It’s fun to design a brand new circuit and to verify the design. Every day I feel like I’m exploring something exciting and a lot needs to be considered to ensure the chip has good circuit design, and to satisfy all the specifications. For example, we need to make sure the chip has very low power consumption.
Nhan: Circuit design can be applied to many different purposes. But when we apply it for a medical purpose, it’s more difficult, especially for implantable devices. There are size constraints and power constraints, and it has to pass the United States Food and Drug Administration compliance process; it’s not the same as the everyday application of electronics. The challenge is different from other electronic work, and that’s what I like. We get to learn about things other than just electronics, like biomedical science and physics. We can build a chip, we can make it work, but to have a chip implanted inside a person, a human being, is another story.
What are some of the biggest challenges facing young researchers in Australia?
Nhan: The industry in Australia is very young. We have no fabrication facility in the country. For circuit designers, we don’t get many opportunities to have the chips fabricated, so we have to get it right the first time. I’d like to see some more support for this area; if we had fabrication facilities in the country, young researchers could be trained to use this sophisticated lab equipment.
When the work is challenging, what motivates you to keep going?
Jeff: The purpose of our work is to help people who have vision loss. It’s great if our products can really help those people, and it makes my work meaningful. My research area is low-power electronics for medical devices, and the power consumption is such a critical factor for biomedical implants. I hope my job can make a significant contribution to this area.
Causes of blindness
Retinitis pigmentosa
(also referred to as RP)
Is a group of genetic eye conditions that can lead to complete blindness. In the progression of symptoms for RP, night blindness generally precedes tunnel vision by years or even decades and then sometimes the central vision. Many people with RP do not become legally blind until their 40s or 50s and retain some sight all their lives. Others go completely blind from RP, in some cases as early as childhood. Progression of RP is different in each case. Currently there is no treatment to prevent, halt or reverse retinitis pigmentosa though a number of avenues are being explored including gene therapy and stem cells alongside bionics. Treatment for patients with RP is primarily focused on managing the deterioration of sight by introducing the use of mobility and reading aids. It is thought that one child is born with RP in approximately every 3,000 births in Australia.
Age-related macular degeneration (AMD)
Is the cause of almost half of all legal blindness in Australia. AMD causes cells in the retina, the light sensing part of the eye, to stop converting absorbed light into electro-chemical signals. As the brain does not receive the signal, a complete image is not formed. This results in vision loss in the centre of the visual field and can lead to complete blindness. AMD usually affects people over the age of 65. Patients with AMD have difficulty performing tasks that rely on central vision, such as reading and recognising faces. Presentlyy, there is no cure for AMD, but there are a number of treatments that can slow its progression.
About the project
Wide-view retinal implants builds upon technologies that have successfully been employed in cochlear implants (bionic ear. The key purpose of this device is to assist patients with very low vision move about their environment safely and with greater ease. The High-Acuity device aims to provide functional central vision to the user, to assist with tasks such as face-recognition and reading large print. Bionic Vision Australia is a research consortium bringing together experts from the Centre for Eye Research Australia, the Bionics Institute, NICTA, The University of New South Wales and the University of Melbourne. The Royal Victorian Eye and Ear Hospital, the National Vision Research Institute and the University of Western Sydney are project partners.
This consortium was established in 2010 to develop a functional retinal prosthesis, or bionic eye, that can restore a sense of vision to people with blindness due to inherited and degenerative retinal conditions. The research team includes a diverse group of people with expertise as varied as: ophthalmology, biomedical engineering, materials science, neuroscience, vision science and psychophysicsphyscophysics, wireless integrated circuit design, preclinical, clinical and surgical practice.
Researchers expect to begin patient tests for their Wide-View device as early as next year at the Royal Victorian Eye and Ear Hospital. The wide-view retinal implant combines novel technologies with materials that have been successfully used in other clinical implant, such as the bionic ear. The key purpose of this device is to assist patients with very low vision move about their environment safely and with greater ease.
Patient tests with the High-Acuity device are planned for 2014. The High-Acuity device aims to provide functional central vision to the user, to assist with tasks such as face-recognition and reading large print. To begin with, clinicians are looking for people with blindness due to retinitis pigmentosa, which is an inherited condition. Researchers then plan to work with patients who have age-related macular degeneration.
Dr Jiawei
(Jeff Yang)
Jeff studied a Bachelor of Engineering at Zhejiang University, China. He completed his PhD through NICTA VRL and the University of Melbourne in 2011. He now works in low-powered electronics for medical devices and is building the receiver and transmitter for the high acuity bionic eye microchip.
Dr Nhan Tran
Nhan studied a Master of Engineering at Kyung Hee University, South Korea. In 2011, he completed his PhD through NICTA VRL and the University of Melbourne. Nhan presented his paper on the prototype 64-electrode retinal stimulator and won second prize at the 33rd International Conference of the IEEE Engineering in Medicine and Biology Society.
Bionic Vision Australia was established in 2010 to develop a functional retinal prosthesis, or bionic eye, that can restore a sense of vision to people with blindness due to inherited and degenerative retinal conditions. The research team was compiled in 2011 recruiting a diverse group of people with expertise as varied as: ophthalmology, biomedical engineering, materials science, neuroscience, vision science and physcophysics, wireless integrated circuit design, surgical and clinical practice. Bionic Vision Australia is a national consortium of researchers from a number of universities and research organisations. For more information about Bionic Vision Australia go to bionicvision.org.au
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