Bionic eye

MT5009 BIONIC EYES

Ler Ming Lim A0098570U

Coline Michele Juin A0104445N

Ka Mung Chee A0098573M

Hanisah Hannifah Gupta A0098462U

Kah Heng Cheng A0082075H

Gary Ho Wai Chi A0082062N

For information on other new technologies that are becoming economically feasible,

see http://www.slideshare.net/Funk98/presentations

Presentation Outline

1. How it works

2. Important technological components

i. Electrodes implanted on the eye

ii. Camera Sensor Technology

iii. Video processing unit/Interface to the brain (light-> electrical

signals)

iv. Radio transmitter/antenna

3. Important dimensions of performance

i. surgery time, overall factors

4. Important dimensions of overall cost

5. Improvements/Future opportunities

How a Human eye works

Common Vision Problems

• Problems with the eyes

• Structural

• Solved with corrective eyewear/eye surgery

• Retina / macula => affects light processing

functions

• Cannot be solved with correcive eyewear/surgery

• Bionic eye?

No cure

Types of Visual Prostheses

Based on neuronal electrical stimulation at

different locations along the visual pathway

• cortical

• optic nerve

• epiretinal

• subretinal Retinal

prosthesis is the

most advanced

visual prosthesis

to date

ARGUS II – Most Advanced Retinal Prosthesis

ARGUS II epiretinal implant

largest study of a retinal prosthesis

more than 60 subject years of implant

experience with this device

only FDA-approved study

only retinal implant to get a CE mark

to be sold as a medical device in

Europe

Developed by Second Sight Medical

Products Inc

http://www.youtube.com/watch?featur

e=player_detailpage&v=Bi_HpbFKnS

w

Argus II- How does it work?

Source/ http://youtu.be/Bi_HpbFKnSw

Argus II - How does it work?

What Do Users See?

Source: NY Times, Device Offers Partial Vision for the Blind

Components of Bionic Eye

Camera

Video

Processor

Wireless

Electrodes

Component: Camera Sensor Technology

Camera

Camera Image Sensor Technology

• CMOS Image Sensor has photo diodes (PD), same as CCD Image

Sensor. But there is difference in the mechanism of transmitting

electrons.

• CMOS transmit electrons using the wire;

• Charged Coupled Device aka CCD itself.

• The colored elements in the figure correspond the pixels; In color

cameras, they are usually filtered red, blue and green.

Monochrome (1-bit)

2-bit Grayscale

4-bit Grayscale

8-bit Grayscale

Monochrome Palettes

Camera Module Scaling

Sources: http://image-sensors-world.blogspot.sg/2011/11/st-published-its-tsv-camera-module.html

http://www.chicony.com.tw/products/cm_module/cm.html

Component: Video processing unit

Video

Processor

Video-processing process

Example of

4*4 matrix of

electrode

Current prosthetics use electrodes of optogenetic transducers to allow

users to perceive, as most, "spots of light or high-contrast edges.“ 1

Source: 1) Journal Proceedings of the National Academy of Sciences.

Step 1: simplify the

image => making

just black and white

Step 2: reduce that

image to the

number of

electrode available

Video processor will benefit from IC/SOC

improvement

• As discussed in Lectures, improvements in:

• Costs

• Performances, respond time (need to be real time)

• Size

• Power consumption

Sources: “Bionic eyes”, Anonymous, The Futurist; Sep-Oct 1993; 27, 5; ProQuest, pg. 53

Example of decrease in size: From Argus II to Multi-unit Artificial Retina Chipset

(photosensing, processing, and stimulating chip , 2mm * 2mm)

Improvement of video processing

Original image

Image (reconstructed) for a blind retina

Standard

Optogenetic

prosthetic

Encoder-ChR2

prosthetic

Source: “Retinal prosthetic strategy with the capacity to restore normal vision” Sheila Nirenberg1 and Chethan Pandarinath

Component: Wireless transmission

Wireless

Wireless transmission of Image + Power

Source: Building the bionic eye: an emerging reality and opportunity, Lotfi B. Merabet (2011)

Planned Changes to Marketed Version

of the Systems

Planned Changes:

• Edge of coil suture tab

rounded slightly

• Changed the radio

frequency at which the

glasses communicate to

meet new international

radio communication

standards

• Modified the implant chip

to improve wireless

efficiency

• Externals modified

to improve ergonomics and

ease of programming

Source: INTRAOCULAR RETINAL PROSTHESIS, BY Mark S. Humayun, MD, PhD (2011)

Key Performance Factor

• Surgical Consideration

• Feature size

• Wireless speed, Penetration

• Data integrity

512-Channel Intraocular Epiretinal Implant

Technologies Basic Methods of Improvement

Parylene Flex

Technology. IC chip

•Scale down thanks to high-density multi-channel

integration chip

•Improve wireless penetration and data integrity

•Low cost (wafer size scale up)

3-coil wireless power

transfer

and data coil

interference system

•High signal processing power

•High efficiency up to 36.5%

•Improve safety margin for surgical consideration

Source: PACKAGING STUDY FOR A 512-CHANNEL INTRAOCULAR EPIRETINAL IMPLANT, Jay Han-Chieh Chang (2012)

High-Density Multi-channel Chip

Integration - Parylene Flex Technology

Fabrication process of the Parylene-

C flexible circuit board.

Process flow of conductive epoxy

squeegee technique to make electrical

and mechanical connections between

Parylene flex and chips


3 Coil Wireless Power Transfer

and Data Coil Interference

The 3-coil scheme for inductive

power transfer. A model of the coil system is built

using HFSS for the coil

interference analysis


Component: Microelectrode Array

Electrodes

Microelectrode Array

-Electrode is implanted in the

inner surface of retina

-Conductive tips of each

electrode reside in the

ganglion cell layer

- Electrodes are made by

MEMs

Key Performance Factors

Resolution

Electrode-retina interface performance

Material biocompatibility & Stability

Resolution & Pixel size

Better vision

with smaller

pixel size

Source: Photovoltaic Retina Prosthesis for restoring sight to the blind, Daniel Palanker (2012)

How the eye sight looks, 300um










No. of electrodes have Improved

Made possible by reduction in scale in MEMs manufacturing

Normal vision = more than one hundred million receptors in each eye

Source: The Artificial Retina Progress Report, Craig Blackwell MD (2011)

Are there Physical Limits to Electrode size?

• optimal size of an

electrode should be

comparable to the

cellular size (L ≈ 10

μm), i.e. its radius ro

should be about 5μm.

Electrode

• Charge transfers-

changes of the

electrodes from

positive to negative-

flow of electrons into

the tissue

Source: Electrode-cellular interface. Science .10 April 2009. Vol 324 )

Distance of Electrode to Cells

• Distance between

electrode and retina

is most critical!

• Large distance

requires high charge

for stimulation

• Causes heating of

the tissue

Source: Electrode-cellular interface. Science .10 April 2009. Vol 324 )

Improvement in MEMs Technology

1. 3D Geometry

• Pillar electrode arrays

• Penetrating electrodes

2. Coating to improve electrochemical

performance

• Polymer coating

http://neurotechzone.com/posts/292

Source: Conducting polymers for neural interfaces: Challenges in developing an effective long-term implant. Biomaterials

Volume 29, Issues 24–25, August–September 2008, Pages 3393–3399

Better Materials for Micro-electrode Arrays

Traditional New

Material Metal electrodes (Ir, Pt

or Au)

Nanocrystalline

diamond

Charge Transfer Passive, good

conductor

Good conductor

Contact to neurons Not Optimal, may

cause electrode

degeneration

Good biocompatibility

and bio stability

Does not get degraded

3D shaped mechanically flexible diamond microelectrode arrays for eye implant applications: The MEDINAS project

E - The Development of a Retinal Prosthesis: A Significant Biomaterials Challenge

Improvements and future opportunities

Entrepreneurial Opportunities

US $150,000 4 hours of surgery

Black & White Vision

Improve Resolution Performance

Improve Other Vision Problems

0

200

400

600

800

1000

1200

2000 2010 2020

Nu

mb

er

of

Ele

ctr

od

es

Year

Electrode trend

Argus I

Argus II

Bionic Vision Australia, Wide View Device

Bionic Vision Australia, High Acuity Device

Improvements in Resolution Performance

Source: Bionic Vision Australia, Argus websites

Improvements in Cost

$0

$50,000

$100,000

$150,000

$200,000

2013 2015 2020 2030

Cost Projection of Bionic Eye

Estimated Cost Breakdown

Camera

Electrode

Video Processor

Wireless

Source: McKinnon, B. J. (2013), Cochlear implant programs: Balancing clinical and financial sustainability. The Laryngoscope,

123: 233–238. doi: 10.1002/lary.23651

Potential Applications of this technology/

Future Opportunities

http://youtu.be/iUz1ScDKslk

Source: http://youtu.be/iUz1ScDKslk

Any Questions?

Health & Medicine

Bionic eye