Fractal implants perform well in simulation

The positive results mean researchers from the University of Oregon, headed by Professor Richard Taylor, will now look to focus their efforts on biological testing.Fractal objects have repeating patterns at many scales and are seen in nature in things like tree branches, rivers, snowflakes, blood vessels and neurons. The idea behind Taylor’s implant is to exploit electrodes that have the same fractal shape as the neurons with which they will interact.{{quote-A:R-W:480-Q: Fractal electrodes provide a larger surface area that holds more electrical charge than the traditional devices currently used. }}Taylor’s device is a bio-implant surgically placed behind the retina that features an array of fractal electrodes. These electrodes stimulate retinal neurons, which theoretically should help people diagnosed with diseases such as diabetic retinopathy or macular degeneration achieve better visual acuity.Currently used retinal implants feature electrode shapes based on traditional Euclidean geometry such as squares, but in human clinical trials Euclidean-based devices have only achieved 20/1260 visual acuity, and 86% of cases result in no restored acuity.However, computer simulations of the fractal device indicated it stimulated 90% more neurons while using less voltage. It also has the potential to restore vision to 20/80.A doctoral student of Taylor’s, Mr William Watterson, said the implant was able to do this because the fractal electrodes provide a larger surface area that holds more electrical charge than the traditional devices currently used.{{image2-a:l-w:450}}“Operating under identical conditions in our simulations, we’ve shown that a single fractal electrode stimulates all of the target neurons, while the Euclidean electrode connects with only 10% of th,” he said.Watterson added that fractal implants – which act much like a pixel array at the back of a camera – can efficiently utilise more pixels within the confined space at the back of the eye, providing electrically restored vision at a higher resolution.In retina-damaged eyes the cones and rods that do such intermediate work disappear, however, according to Watterson the fractal implants should be able to stimulate the still-intact neurons.The simulated results have provided information that will help the scientists design miniature versions of the implants for testing in mice where researchers hope to gain a measure of how well such devices may restore vision to humans.