Advances in Bionic Eye Research

Nigel Lovell and Gregg Suaning Graduate School of Biomedical Engineering

University of New South Wales, Sydney

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Biomaterials and tissue engineering

Bionics, biomonitoring and biomodelling

15 Academic and research staff

20 General staff

~50 PhD students + 10 others in Elec Eng

~60 P/G coursework students

~350 BE/MBiomedE students

~> $6 million research income p.a.

GSBmE

Biomonitoring and Bionics

Implantable sensors and devices (bionic eye, heart assist devices)

Wearable sensors for falls detection/prevention (triaxial accelerometer)

Clinical measurements for management of chronic disease (home telehealth)

Unobtrusive monitoring of functional health (sensor networks and telecare integration)

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Electrical/Computer Engineering interface with Medicine

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Wireless sensor networks Embedded systems Electrical and biosignal processing Microelectronics Miniaturisation - nanotechnologies Control systems for heart pumps Computational modeling

IRBP dP sensor

IRBP

LVP sensor

IRBP flow Aortic and PA flow sensors

Retinal Disorders

End Stage RP 5

RP

AMD IEAust 2012

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The Problem

Together, AMD and RP affect at least 30 million people in the world

6,500 cases of RP in Australia and 87,000 in the USA

AMD currently costs Australia $2.6bn p.a.

For RP there is no effective means of restoring vision

Retinitis Pigmentosa (RP)

Age-related Macular Degeneration (AMD)

Oops!!

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Retinal Remodelling

Marc et al, Prog Retinal and Eye Res, 22, 2003

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Blind (A) and Sighted (B) Subjects – Finger Tapping Task

Gizewski et. al., Neuroimage, 19, 2003

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Blind (A) and Sighted (B) Subjects – Reading Braille with Right Hand

Gizewski et. al., Neuroimage, 19, 2003

Brindley, Donaldson and Lewin, 1968

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Optic Nerve Implants

Retinal Implants

Cortical Implants

How Does Our Bionic Eye Work?

1. Camera captures

vision and

transmits data to an

external, body worn

processing unit

4. Implanted

electrode array

stimulates retina

3. Implanted

receiver passes

signals onto retinal

implant

2. Data

processed and

sent to implanted

system via

external wire

5. Electrical

signals sent from

retina via visual

pathway to vision

processing centres

in the brain

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The Olden Days...(1997)

Nigel Lovell UNSW

(Cardiac Research and

Telehealth)

Gregg Suaning Manager of Process

Development Engineering -

Cochlear (Implant Research)

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The Plan Back Then: Human Implants by 2000

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First generation implant One hundred stimulation channels Series stimulation Biphasic constant current waveforms RF (inductively-coupled) data and power Reverse telemetry Ceramic and epoxy package PDMS and platinum electrode array

The Plan Back Then: Human Implants by 2000

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The Reality: Sheep Implants by 2000

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Back to the Drawing Board

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Click Image to Play Video

International Approaches

German – VC funded founded 2003 Clinical trials (Zrenner group)

Second-Sight

US – VC & Govt funded

Clinical trials conducted

Argus II on the EU market

Com

me

rcia

l

German-Swiss – VC & Govt funded

Aca

de

mic

Optoelectronic Retinal Prosthesis (Palanker group)

Mass Eye and Ear / MIT (Rizzo & Wyatt group)

Intelligent Medical

Implants (IMI)

France: Institut de la Vision Paris

Japan: Medicine, Nagoya Uni

Korea: Seoul Artificial Eye Center

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Epi-Ret-3

Optobionics Second Sight Argus I

16 Retina Implant

1500

EpiRet

25

IMI

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Second Sight Argus II

60

Clinical Trials

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Laboratory and Cleanroom Facility

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External Hardware

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Split Architecture

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Laser Micromachining

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Titanium+

alumina 'hybrid'

Titanium lid

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Ceramic and Titanium Encapsulation

Implant Research:

High Density Ceramic Feedthroughs

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98-Channel Electrode Array

1 2

3

5

4

6

Comparison of Laser Cuts

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PDMS Ablation - Excimer Laser

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Electrode Surface Roughening

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98-Channel Electrode Array

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Bioinspiration

Fluorescent images of

Drosophila (fly) retina 42

hours after pupal

development

SEM of an adult fly eye

showing near perfect rows

of ommatidia or unit eyes

arrayed hexagonally

Concurrent Stimulation

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Austriamicrosystems AMS

H35B4D3 4M 2P process

Scalable architecture

98 channels of stimulation

Up to 14 channels

in parallel

Constant current

Biphasic stimuli

Post-stimulus shorting

Monolithic

Reverse telemetry

Quasi-Monopolar

Monolithic Neurostimulation Chip

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Prototype Implanted Device (Eye Unit)

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Does the Device Work?

“What do you see?”

Baa Baa

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The Science: Device Efficacy and Stimulation Strategy

Biomathematical modelling

Surgical placement

In vivo animal experiments (multi- electrode arrays)

In vitro animal experiments (patch clamping, extra-cellular recording, two-photon imaging)

Simulated psychophysics

Human psychophysics …

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Modelling: Current Containment

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Electrode Interaction

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Supra-Choroidal Implantation

Courtesy of Chris Williams,

Penny Allen, BEI/RVEEH

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Device Placement

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Patch Clamp and Sharp Microelectrode Electrophysiology

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The Neural Code

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Two-Photon Microscopy

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Click Image to View Video

Simulated Prosthetic Vision

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Click Image to View Video

Head movement allows identification of difficult

Landolt C items. This movie demonstrates some very

difficult test items, but were all identified correctly by

subject.

Images at NICTA CRL trial environment; various representations

based on depth, intensity, contrast etc.

Incorporating Depth Mapping

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Science Fact or Science Fiction

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Summary

Suprachoroidal space appears to be a viable position for a visual prosthesis

Differentiator - smart visual processing and current steering strategies to create ‘virtual phosphenes’

Human trials of our device this time in 2013

Current neuroprostheses rely on microtechnologies to fabricate and service electrodes >500 m in size (typically interfacing to thousands of nerve fibres)

Unlikely that 1000+ electrode devices will be approved by regulatory bodies in next few years

Either need disruptive technologies to solve the wiring, feedthrough and hermeticity issues or tissue engineering approaches? …

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http://bionic.gsbme.unsw.edu.au

http://www.bionicvision.org.au

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twitter.com/bionicvision