A technical paper which throws light on the idea of combining Technology with Biology in order to provide a solution to visually impaired people

1. www.ijsetr.com
ISSN 2319-8885
Vol.04,Issue.36,
September-2015,
Pages:7862-7864
Copyright @ 2015 IJSETR. All rights reserved.
Bionic Eye-A Vision of Hope
MOHIT KHATRI
1
, SALIL VAIDYA
2
, MANAS KARANJEKAR
3
1
B.E Student, V.E.S Institute of Technology, Mumbai, India, E-mail: mohit.khatri@ves.ac.in.
2
B.E Student, V.E.S Institute of Technology, Mumbai, India, E-mail: salil.vaidya@ves.ac.in.
3
B.E Student, V.E.S Institute of Technology, Mumbai, India, E-mail: manas.karanjekar@ves.ac.in.
Abstract: 'Bionics' is an amalgamation of the words 'biology' and' electronics'. The 'Bionic Eye' utilizes a digital camera installed
on a pair of glasses and a video-processing micro-chip implanted in the eye. The camera captures images and transmits this data to
the chip which performs image sharpening, restoration, pattern analysis and recognition. An array of electrodes embedded on the
chip send out electrical impulses on the optic nerves connected to the vision processing centres of the brain, where they are
interpreted as an image. The continuous reception, analysis and transmission of signals along the optical nerve of the brain
enables a visually-impaired person to perceive objects.
Keywords: Prosthesis, Cortex, Implants, Phosphene, Transcranial.
I. INTRODUCTION
The current population of blind people is 285 million and
with the need for eye donors increasing, the actual amount of
people willing to donate is much less. The bionic eye
provides a feasible solution to this problem. The basic idea
behind the working of the device is stimulation of brain cells.
A phosphene is aphenomen on characterized by the
experience of seeing light without light actually entering the
eye. The word phosphene comes from the Greek word sphos
(light) and phainein (to show). Phosphenes that are induced
by movement or sound are often associated with
opticneuritis. Phosphenes can be directly induced by
mechanical, electrical, or magnetic stimulation of the retinaor
visual cortex as well as by random firing of cells in the visual
system. Phosphenes have also been created by electrical
stimulation of the brain, reported by neurologist Otfrid
Foersterasearlyas1929. Brindley and Lewin (1968)inserted a
matrix of stimulating electrodes directly into the visual cortex
of a 52-year-old blind man, using small pulses of
electricity to create phosphenes. These phosphenes were
points, spots, and bars of colorless or colored light. Brindley
and Rushton (1974) used the phosphenes to create a visual
prosthesis, in this case by using the phosphenes to
depict Braillespots.
Inrecent years, researchers have successfully developed
experimental brain computer inter facesor neuropros thesis
that stimulate phosphenes to restore vision to peopleblinded
through accidents. Notable success include the human
experiments by William.H.Dobelle and Mark Humayun and
animal by Dick Normann. A non- invasive technique that
uses electrodes on the scalp, transcranial magnetic
stimulation, has also been shown to produce phosphenes.
Experiments with humans have shown that when the visual
cortex is stimulated above the calcarine fissure, phosphenes
are produced in the lower part of the visual field, and
viceversa. Damaged photo receptors in the eye are one of the
major causes for blindness. The spatial mapping is plausibly
consistent between the reception at the retina and the initial
image processing centerV1ofthebrain. Failure of the damaged
photo receptors in the retina can be reinstated using Photo
diodes which are implanted with in this space. For every
1mm2 photoreception area of dedicated to fovea(central)
vision,correspondsa500 sq.mm processing area of the cortex.
The process of implantation is expedient and feasible as the
V1 region lies on the surface of the brain and is easily
accessible through a craniotomy.
II. PROSTHESISIMPLEMENTATION
A bionic eye consists of a camera that captures real time
videos and a micro chip implanted in the retin a.Certainly,
the implant hardware is the most important component in the
bionic eye, and the clinic alurgery is the most critical process
towards the success of these bionic eyes as shown in Fig.1.
However, current hardware technology limits the image
resolution of the implant device to be extremely
low.A100stimulation electrode array implant, which amounts
to approximately 12*9 pixel resolution, would be the most
reasonable and affordable device in the market for a number
of years. Therefore, it necessitates a visual processing unit to
provide useful information for microchip. The neuronal cell
bodies connecting the retina and the brain have dendrites
providing the input stimulation and axons as their outputs.
The stimulation caused by the potential field in the neuronal
cell bodies is mainly of the axons. An axon can be considered
as an insulating tube filled with conducting ions. Through the
membrane forming the tube are voltage-gated channels and
ion pumps. The ion pumps maintain a high concentration of

2. MOHIT KHATRI, SALIL VAIDYA, MANAS KARANJEKAR
International Journal of Scientific Engineering and Technology Research
Volume.04, IssueNo.36, September-2015, Pages: 7862--7864
potassium with in the axons, which causes a potential across
the axon’s membrane–the resting potential, whichisaround-
70mV.Ifthispotentialcan be madeless negative, voltage-gated
sodium channels will open, causing a huge increase
in(ionic)permeability for sodium which has a high
concentration outside the axon.
This causes the membrane potential to move positive,
creating an‘action potential’. This spike then propagates
along the axon to neighboring voltage-gated channels,
causing them to open. Thus, if we can alter them embrane
voltage at any part along the axon, we can get the channels to
open, and the axon to transmit a‘false’ message along itself to
neurons. This occurs if there is a sufficient transient
longitude in al field gradient imposed along the axon.
Typically 50μApulses of100μsduration will cause a visual
sensation. Normally a pulse of the opposite polarity is then
applied to discharge the charge around the electrode, which
can cause bio compatibility problems if too much charge
accumulates. Since we are penetrating the cortex, we can
getreasonably localized stimulation around ach electrode,
thus each electrode generally gives rise to a separate visual
sensation, or phosphene, which appears as agrey or colored
disk. We are placing our electrodes at aspacing of
approximately 1mm, for a variety of reasons including
reducing mechanical damage to the brain.
Fig.1.Internal Structure of a Bionic Eye.
III. FUNCTIONING OF PROSTHESIS
The working of the prosthetic unit is divided among three
units-
A. Camera and Image Processing Unit
High-resolution camera is installed on the glasses worn by
the deceased who provides continuous feed of images to a
Processor which employs signal processing techniques such
as transformative reality.
B. Wireless Power and Data Link
Multiple implant tiles consisting of inductive links with
tuned resonating transmitter and receiver coils is used to feed
data to the ASIC unit as shown in Fig.2. Resonance is used to
maximize power efficiency between transmitter and receiver.
The data fed by the processor is Amplitude modulated.
Fig.2. ASIC Unit.
C. Implant Tile
Amplitude demodulation takes place within the Implanttile.
The ASIC is connected to the electrodes via a multi-layer
distribution board which send electrical signals along the
optic nerves as shown in Fig.3. The ASIC contains sufficient
registers so that the pulse parameters for each electrode can
beset individually via the wireless link. A brown-out
detection circuit ensures that the link is reset if the registers
lose power and become corrupted. The electrodes then can be
commanded to produce a pulse.
Fig.3. Implant Tiles.
IV. CONCLUSION
In this paper, we have summarized the primary Bionic Eye
proto type. Multiple disciplines work in harmony and have
been successfuling enerating an approximate though not
accurateimagery which can help the visually impaired
avoiding obstacles at a very basic level. The bionic eye has
proven to be exemplary to the evolution of technology
deployed for a noble cause.
V. REFERENCES
[1]Technical paperon ‘Cortical Prosthesis’ by Arthur James
Lowery of Monash Vision Group.

3. Bionic Eye-A Vision of Hope
International Journal of Scientific Engineering and Technology Research
Volume.04, IssueNo.36, September-2015, Pages: 7862-7864
[2]Technical paperon‘ Psychophysics testing of bionic vision
image processing’by Horace Josh, Collette Mann, Lindsay
Kleemanand Wen Lik Dennis Luiof Monash Group.
[3]TheIEEEwebsite.[Online].Available: http://www.ieee.org/
[4]Bionic Eye website [Online] Available. http://
bionicvision.org.au/eye.
[5]To study about the Human brain -http://thebrain.
mcgill.ca.
[6] http://ieeexplore.ieee.org/Xplore/home.jsp.