Seeing little more than blob-like shapes as she navigated her way towards a target on the far wall was a major thrill for Dianne Ashworth. She has been blind for more than 20 years.
This week she reached a milestone. For the first time since losing her sight Dr Ashworth was able to walk and navigate her way without relying on her guide dog.
‘’It’s been amazing,’’ she said. ‘’The more I’ve been doing it, the more natural it feels.’’
Using 20 electrodes in her 24-electrode bionic eye, Dr Ashworth was also able to get a sense of distance, with the electrical signals she sees intensifying as she got closer to her target.
Visiting Canberra from Melbourne this week to test the vision processing component of her bionic eye, she is one of three patients who are trialling an early prototype, which has been in development since 2010.
This trial marked the first time the three patients, Dr Ashworth, Murray Rowland and Maurice Skehan – who all lost their sight to the inherited condition known as retinitis pigmentosa – could test the device while mobile.
Previously the trio only had the bionic eye activated when they were desk-bound, responding to objects as they appeared on a computer screen.
They took their first steps this week as a team of scientists from the ICT research centre NICTA looked on.
‘’It’s gone wonderfully,’’ said NICTA computer vision researcher Nick Barnes. ‘’So far it’s probably better than we expected. It’s really promising.’’
In controlled conditions the patients have been navigating their way towards a target on the far wall of a room. The exercise is repeated up to 100 times, with the target and starting point changing each time. Some tests also have obstacles placed on the floor that patients have to navigate their way around.
They are measured on the time it takes to find the target, their accuracy in locating the target and how early they are able to orient themselves towards the target.
What the patients see is nothing like regular vision, but rather a low-resolution image of about 20 pixels. And it differs from person to person. While Dr Ashworth sees blob-like shapes, Mr Rowland described seeing flashes of lightning in a storm.
Professor Barnes said the early results showed that even a device with limited electrodes such as this prototype was able to provide patients with enough visual information to become mobile. The same Bionic Vision Australia group developing this device is also working on a high-acuity bionic eye with 256 electrodes. It is hoped that will be ready for patient trials as early as this year.