2. CONTENTS
Human Eye
About Bionic Eye
Blindness Diseases
Artificial Silicon Retina
Multi Unit Artificial Retina Chipset
Conclusion
Department of ECE Engineering
,SDMCET Dharwad-02 2
3. About Bionic Eye
Bionic eye’ also called a Bio Electronic eye.
An electronic device which replaces functionality of a
part or whole of the eye.
The entire electronics system consists of the image
sensors, processors, radio transmitters &
receivers, and the retinal chip.
Department of ECE Engineering
,SDMCET Dharwad-02 3
4. Human Eye
We can see when light from an object move through
space and reach our eyes.
Scattered light from the object enters through the
cornea.
The light is projected onto the retina. The retina
sends messages to the brain through the optic nerve.
The brain interprets what the object is.
Department of ECE Engineering
,SDMCET Dharwad-02 4
6. More About Human Eye
The important part of an eye that is responsible for
vision is retina. The retina is complex in itself.
This thin membrane at the back of the eye is a vital
part of your ability to see.
Main function of retina is to receive and transmit
images to the brain.
Department of ECE Engineering
,SDMCET Dharwad-02 6
7. Human Eye(con’t)
In humans there are three main types of light
sensitive cells in the retina. They are
Rod Cells
Cone Cells
Ganglion Cells
There are about 125 million rods and cones within
the retina that act as the eye’s photoreceptors.
Department of ECE Engineering
,SDMCET Dharwad-02 7
8. Human Eye(con’t)
Rods are able to function in low light and can create
black and white images without much light.
Once enough light is available, cones give us the
ability to see color and detail of objects.
The information received by the rods and cones are
then transmitted to the nearly one million ganglion
cells in the retina.
These ganglion cells interpret the messages from the
rods and cones and send the information on to the
brain by way of the optic nerve.
Department of ECE Engineering
,SDMCET Dharwad-02 8
9. Blindness
Blindness means loss of vision.
Rods and Cones are biological solar cells in the retina
that convert light to electrical impulses which travel
along the optic nerve to the brain where images are
formed.
Without them, eyes lose the capacity to see, and are
declared blind.
Degenerative retinal diseases result in death of
photoreceptors .
Rod-shaped cells at the retina's periphery are
responsible for night vision and cone-shaped cells at
its center responsible for color vision.
Department of ECE Engineering
,SDMCET Dharwad-02 9
10. Retinal Diseases
There are a number of retinal diseases that attack
these cells, which can lead to blindness. The most
notable of these diseases are:
1.Retinitis Pigmentosa (RP)
2. Age-related macular degeneration(AMD)
Together, AMD and RP affect at least 30 million
people in the world. They are the most common
causes of untreatable blindness in developed
countries and, currently, there is no effective means
of restoring vision
Department of ECE Engineering
,SDMCET Dharwad-02 10
11. Retinitis Pigmentosa (RP)
RP is a general term for a number of diseases that
predominately affect the photoreceptor layer or “light
sensing” cells of the retina.
These diseases are usually hereditary and affect
individuals earlier in life.
RP affects the mid-peripheral vision first and sometimes
progresses to affect the far -periphery and the central
areas of vision. The narrowing of the field of vision into
“tunnel vision” can sometimes result in complete
blindness.
Department of ECE Engineering
,SDMCET Dharwad-02 11
13. Age-Related Macular
Degeneration(AMD)
AMD refers to a degenerative condition that occurs
most frequently in the elderly.
AMD is a disease that progressively decreases the
function of specific cellular layers of the retina’s
macula.
It degenerates cones in macula region, causing
damage to central vision but spares peripheral
retina, which affects the ability to read and perform
visually demanding tasks.
Although macular degeneration is associated with
aging, the exact cause is still unknown
Department of ECE Engineering
,SDMCET Dharwad-02 13
15. Bionic Eye : Two Approaches
There are two approaches by which we can implant
a bionic eye:
Artificial Silicon Retina – ASR
Multi-unit Artificial Retina Chipset - MARC
Department of ECE Engineering
,SDMCET Dharwad-02 15
16. Artificial Silicon Retina
(ASR)
The ASR is a silicon chip 2 mm in diameter and
1/1000 inch in thickness.
It contains approximately 3,500 microscopic solar
cells called "microphotodiodes," each having its own
stimulating electrode.
These micro photodiodes are designed to convert the
light energy from images into thousands of tiny
electrical impulses to stimulate the remaining
functional cells of the retina in patients suffering with
AMD and RP types of conditions.
Department of ECE Engineering
,SDMCET Dharwad-02 16
17. ASR (con’t)
The ASR is powered solely by incident light and does
not require the use of external wires or batteries.
When surgically implanted under the retina, in a
location known as the sub retinal space, the ASR is
designed to produce visual signals similar to those
produced by the photoreceptor layer.
From their sub retinal location these artificial
"photoelectric" signals from the ASR are in a position
to induce biological visual signals in the remaining
functional retinal cells which may be processed and
sent via the optic nerve to the brain.
Department of ECE Engineering
,SDMCET Dharwad-02 17
19. Multi-unit Artificial Retina Chipset
(MARC)
The other revolutionary bio electronic eye is the
MARC.
This uses a CCD camera input and a laser beam or RF
to transmit the image into the chip present in the
retina.
Using this, a resolution of 100 pixels is achieved by
using a 10x10 array.
It consists of a platinum or rubber silicon electrode
array placed inside the eye to stimulate the cells.
Department of ECE Engineering
,SDMCET Dharwad-02 19
20. More about MARC
MARC basically consists of
A secondary receiving coil mounted in close
proximity to the cornea.
A power and signal transceiver.
A processing chip.
A stimulation-current driver and a proposed
electrode array fabricated on a material such as
silicone rubber thin silicon or polyimide with ribbon
cables connecting the devices.
Department of ECE Engineering
,SDMCET Dharwad-02 20
21. MARC (con’t)
An external miniature low-power CMOS camera worn
in an eyeglass frame will capture an image and
transfer the visual information and power to the
intraocular components via RF telemetry.
The intraocular prosthesis will decode the signal and
electrically stimulate the retinal neurons through the
electrodes in a manner that corresponds to the image
acquired by the CMOS Camera.
Department of ECE Engineering
,SDMCET Dharwad-02 21
24. Outside Eye:
The video input to the marc system block is given
through a CCD camera.
This image is further processed using a PDA sized
image processor & to transmit it, we do pulse width
modulation in first stage and then ASK modulation is
done.
This signal is further amplified using a class E power
amplifier and transmitted using RF telemetry coils.
Department of ECE Engineering
,SDMCET Dharwad-02 24
25. Inside Eye:
The signal received from the RF telemetry coils is
power recovered and then these signal is ASK
demodulated and the data and clock is recovered
from this signals .
These signals are sent to the configuration and
control block of the chip which from its input decode
what information has to be sent to each of the
electrodes and sends them this data.
The electrodes in turn stimulate the cells in the eye
so as to send this stimulation to the brain through
optic nerve and help brain in visualizing the image.
Department of ECE Engineering
,SDMCET Dharwad-02 25
26. CHALLENGES
Current retinal implants provide very low resolution
just a few hundred pixels.
There are many doubts as to how the brain will react
to foreign signals generated by artificial light sensors.
Expensive, too clunky and too fragile to withstand
decades of normal wear and tear.
There are 120 million rods and 6 million cones in the
retina of every healthy human eye. Creating an
artificial replacement for these is no easy task.
Department of ECE Engineering
,SDMCET Dharwad-02 26
27. On-Going Development:Argus III
The Argus III will work by taking the image from a
camera and wirelessly transmitting it to an electronics
package. That package will stimulate undamaged retinal
tissue using a thin film transistor electrode array.
Department of ECE Engineering
,SDMCET Dharwad-02 27
28. Conclusion
About 1.5 million people worldwide have Retinitis
Pigmentosa, and one in 10 people over the age of 55
has age related macular degeneration.
The invention and implementation of artificial eye
could help those people.
Bionic eye may not restore the vision completely but
can help patients to least to find their way, recognize
faces, read books, above all lead an independent life .
Department of ECE Engineering
,SDMCET Dharwad-02 28
29. References
IJCST Paper Artificial Vision-A Bionic Eye Vol 3, Issue
1, Jan-March 2012
James D. Weiland and Mark S. Humayun. "Retinal
Prosthetic Systems for Treatment of Blindness”
Frontiers of Engineering 2011: Reports on Leading-
Edge Engineering from the 2011 Symposium.
Washington, DC: The National Academies
Press, 2012, pp. 115–121
www.stanford.edu
www.bionicvision.org
Department of ECE Engineering
,SDMCET Dharwad-02 29
