Retinal Prostheses Anthony Burkitt Presentation
Transcript of Retinal Prostheses Anthony Burkitt Presentation
-
8/7/2019 Retinal Prostheses Anthony Burkitt Presentation
1/20
1
Retinal Prostheses for People
who are Vision Impaired
Deafblind Conference, 28th April 2010
Anthony N. BurkittElectrical & Electronic EngineeringThe University of Melbourne
Retinal Prosthesis (Bionic Eye)
Components:
Camera: mounted on glasses externally
Vision processing unit: Converts image to electrical
impulses (worn externally)
Transmitter: Sends data and power (worn externally)
Receiver unit: Receives data and power (implanted)
Electrode array: Delivers electrical impulses to retina
(implanted)
-
8/7/2019 Retinal Prostheses Anthony Burkitt Presentation
2/20
2
Bionic Eye
Image
Processor
Power
Supply
Power/Data
Transmitter
Camera
Implanted
Receiver/Stimulator
Battery
IMAGE
PROCESSOR
Transcutaneous
Power/Data LinkIMPLANT
Power
Data
Telemetry
Bionic Eye
-
8/7/2019 Retinal Prostheses Anthony Burkitt Presentation
3/20
3
The Eye
Retinal Diseases
light
-
8/7/2019 Retinal Prostheses Anthony Burkitt Presentation
4/20
4
The clinical need
Retinitis Pigmentosa (RP)- Leading cause of inherited blindness.
- 1.5 million people affected worldwide.
- 25% of RP patients legally blind
Age-related MacularDegeneration (AMD)
- Major cause of severe vision loss inWestern countries.
- 1/1000 people affected world wide.
- Currently costs Australia $2.6bn p.a.
- 1-2% of AMD patients legally blind
Two major retinal diseases are the target for a bionic eye.
International approaches
German VC funded founded 2003
Have conducted preclinical trials(Zrenner group)
Second-Sight
US VC & Govt funded
Clinical trials conducted
Commercial
German-Swiss VC &Govt funded
Academic
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
-
8/7/2019 Retinal Prostheses Anthony Burkitt Presentation
5/20
5
BVAs Wide-View Neurostimulator
(suprachoroidal)
TRANSMITTER COILCAMERA
98 ELECTRODEARRAY
98 ELECTRODEARRAY
CHOROIDSCLERA
VISION PROCESSOR
ELECTRONICS UNIT
CHOROID
SCLERA
WHAT WILL I SEE? WHAT WILL I LOOK LIKE? WHAT IS IMPLANTED?
Normal
vision:
Anticipated
vision:
A wide-view neurostimulator provides mobility through
navigation and avoidance of obstacles
A wide-view neurostimulator provides mobility through
navigation and avoidance of obstacles
BVAs High-Acuity Neurostimulator (epi-retinal)
TRANSMITTER COIL
CAMERA
1000 ELECTRODE ARRAY &SIMULATOR
WIRELESS TRANSMISSION
VISION PROCESSOR
32 x 32 ARRAY
Second
Prototype
vision
WHAT WILL I SEE? WHAT WILL I LOOK LIKE? WHAT IS IMPLANTED?
A high-acuity neurostimulator provides face recognition
and large-print reading ability
A high-acuity neurostimulator provides face recognition
and large-print reading ability
-
8/7/2019 Retinal Prostheses Anthony Burkitt Presentation
6/20
6
Implant placement in eye
Phosphene Vision
Electrical stimulation produces
phosphenes.
Phosphene vision:
Induced perception of light bymeans other than light entering
the eye.
-
8/7/2019 Retinal Prostheses Anthony Burkitt Presentation
7/20
7
Electrical stimulation
Electrical stimulation
Electrical pulses
Which electrode
Number of electrodes
Amplitude &Frequency
Perception
Phosphenes
Position
Acuity
Brightness
Retinotopic map of visual field
What do you see here?
16 Phosphenes
-
8/7/2019 Retinal Prostheses Anthony Burkitt Presentation
8/20
8
64 Phosphenes
What do you see here?
1000 Phosphenes
What do you see here?
-
8/7/2019 Retinal Prostheses Anthony Burkitt Presentation
9/20
9
Original Picture
What do you see here?
16 Phosphenes
Can you read this?
-
8/7/2019 Retinal Prostheses Anthony Burkitt Presentation
10/20
10
64 Phosphenes
Can you read this?
1000 Phosphenes
Can you read this?
-
8/7/2019 Retinal Prostheses Anthony Burkitt Presentation
11/20
11
Original Text
Can you read this?
The key scientific challenges
1. Electrode-neural interface
Ability to stimulate neural tissue reliably
Stable long-term interface, without causing damage
2. Localized visual perception
Charge distribution in localized area within retina Evoke multiple phosphenes across the visual field in blind humans
3. Long-term biostability and encapsulation
Safe inert materials
Life-long hermeticity
-
8/7/2019 Retinal Prostheses Anthony Burkitt Presentation
12/20
12
Core Device Development Stream
Common hardware interface to implant:
External vision processor:
Image capture, stimulus
encoding, wireless power and
data transfer.
Implanted receiver-controller:
A behind-the-ear implant to
receive power and data
wirelessly.
Ocular implant device:
Implanted near site of
stimulation on sclera.
Wide-View Neurostimulator Electronics
98 stimulation channels toprovide mobility and objectrecognition.
-
8/7/2019 Retinal Prostheses Anthony Burkitt Presentation
13/20
13
Multi-layered, biologically-inert,high-density electrode arraysmade from Pt and medical gradesilicone.
Supra-choroidal placementprovides robust tissue interfacingon all electrodes
Laser-induced surfacemodifications electrodes improvecharge-carrying capacity.
Wide-View Neurostimulator Electrodes
Hermeticity is key to devicelongevity
Material composition of the
hermetic feedthrough consists ofonly Al2O3 ceramic and platinumconductors.
98 channels are readily achievedwith this approach.
Wide-View Neurostimulator Encapsulation
-
8/7/2019 Retinal Prostheses Anthony Burkitt Presentation
14/20
14
High-Acuity Neurostimulator
Key issues:
Electrode-tissue interface: safe and high-acuity (e.g. face recognition).
Wireless power and data: safe and efficient.
Implantable microelectronics: low-power and flexible.
Device encapsulation: safe and hermetic.
Strategy:
Advanced materials and newcircuit designs.
World leading expertise inmaterials, microelectronics,wireless data and powertransmission, medicalbionics.
Electrical Stimulation can Restore Vision
Design
boron dopedconductive channel
.
chipsolder ball
electrode tip (Pt, Ir)
diamond
5000 m
~150 m
~ 5 m
60 m
Design
boron dopedconductive channel
.
chipsolder ball
electrode tip (Pt, Ir)
diamond
5000 m
~150 m
~ 5 m
60 m
High density electrode array: >1000 in 5 5 mm.
Close proximity to neurons: < electrode pitch (i.e. < 150 m)
Hermetically sealed feed-through
Response threshold < safe charge density
Minimise impedance
Biocompatible
-
8/7/2019 Retinal Prostheses Anthony Burkitt Presentation
15/20
15
High-Acuity Neurostimulator
Electrode-tissue interface: safe and high-acuity
Penetrating
Diamond
Wireless data and power: safe and efficient
Data transceiver < 1 mW
30 mW power deliveredwell within SAR safety limit (2W/kg)using two-pair coils
Intermediatecoils
Secondarycoil
Primarycoilskin
hole thru bone
Data
402MHz
Power5 MHz
penetratingdiamondelectrode
Chronic implantation of electrode materials for biocompatibility evaluation:
Acute study of device performance and surgical safety in animal model
Preclinical Program
5V
20 ms
5V
20 ms
retinaimplant
sclera
biomaterial histopathology
acute implantation OCT imaging electrode voltage electrophysiology
-
8/7/2019 Retinal Prostheses Anthony Burkitt Presentation
16/20
16
Stimulation Strategy Program
Computational modelling of concurrent stimulation and retinal activation
Goal: To understand how best to evoke perception of consistent, stable,localised phosphenes in multiple locations
Stimulation Strategy Program
Our patented hex-guard electrode arrangement gives localized potential inretinal models, in vitro, and in vivo.
-
8/7/2019 Retinal Prostheses Anthony Burkitt Presentation
17/20
17
Stimulation Strategy Program
Psychophysics (normally sightedindividuals and implant recipients)
Landolt C (broken ring) test
Stimulation Strategy Development -Psychophysics Key psychophysics questions :
How to control visual percepts from a single electrode?
How to control visual percepts from multiple electrodes?
How are the dynamic properties of electrical stimuli perceived?
Wide-view neurostimulator: Developing strategy to encoding distance asbrightness of the image.
High-acuity neurostimulator: Developing strategy to aid facial recognition,object recognition, and hand-eye coordination.
Preliminary data have been obtained with normally-sighted people.
-
8/7/2019 Retinal Prostheses Anthony Burkitt Presentation
18/20
18
Surgical Program
High-Acuity Neurostimulator
Surgical placement studies of high-acuity neurostimulator
In vivo OCT scan of retina
Clinical Program
Objectives:
Accurate pre-operative assessment of potential implant candidates
Appropriate post-operative management of patients to optimiseimplant use
Pre-implant: Use state of the art imaging and visual function analysis for:Determine suitability of potential candidates
Correlate structure and function of retina
Post-implant:
Correlate patient performance with
location of implant
-
8/7/2019 Retinal Prostheses Anthony Burkitt Presentation
19/20
19
Clinical Program
Objective is to develop clinical assessment tools for patient suitability, eye
health, visual function, functional vision, visual training, & rehabilitation
CERA, BEI and RVEEH will collaborate to deliver:
Protocols and preliminary data for:
assessment of patient suitability
assessment of eye health & visual function post-implantation
assessment of functional vision in daily life
Fitting software for customisation to individuals
Training and rehabilitation programs post-implantation
Competitive advantage
The Team:
Each world-leaders in their respective fields
Cover all aspects of the design and implementation
Have a solid track record
Work together as a team
The Technology:
Integrated circuit and wireless technology
Implant design, function and encapsulation
Biocompatibility and biological safety techniques
Ophthalmology and eye surgery, inc. clinical expertise
Neural stimulation techniques
-
8/7/2019 Retinal Prostheses Anthony Burkitt Presentation
20/20
AcknowledgmentsUniversity of Melbourne
Steven Prawer, David Grayden, Frank Caruso
NICTA
Stan Skafidas, Nick Barnes, Hamish Meffin, Mark Halpern, David Ng,Tania Kameneva, Nick Opie, Emily OBrien, Jiawei Yang, Bai Shun,Nang Trann, Clive Boyd
Bionic Ear Institute
Rob Shepherd, James Fallon, Chris Williams, Rodney Millard, MarkHarrison, Mohit Shivdasani, Joel Villalobos
Centre for Eye Research Australia (CERA)
Robyn Guymer, Chi Luu, Penny Allen, Mark McCombe, WilliamCampbell
University of NSW (UNSW)
Nigel Lovell, Gregg Suaning, Torsten Lehmann; Philip Byrnes-Preston
Australian National University (ANU)
Michael Ibbotson
University of Western Sydney (UWS)
John Morley
Thank you!