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                                   BIONIC EYE




                                              ten diodes, transistors, resistors and
ABSTRACT:                                     capacitors, making it possible to fabricate
                                              one or more logic gates on a single
                                              device. Now known retrospectively as
                                              "small-scale integration" (SSI),
        Imagine by placing VLSI circuits      improvements in technique led to devices
in the eye of a person with a defective       with hundreds of logic gates, known as
eye, we can increase the efficiency and       large-scale integration (LSI), i.e. systems
improve the sight of that. Appropriately      with at least a thousand logic gates.
saying to create sight to the blind using     Current technology has moved far past
VLSI designs                                  this mark and today's microprocessors
                                              have many millions of gates and
                                              hundreds of millions of individual
         Very-large-scale integration         transistor
(VLSI) is the process of creating
integrated circuits by combining
thousands of transistor-based circuits into
a single chip. VLSI began in the 1970s
when complex semiconductor and
communication technologies were being
developed. The microprocessor is a VLSI
device. The term is no longer as common
as it once was, as chips have increased in
complexity into the hundreds of millions      BIONICS:
of transistors.


        The first integrated circuits held          The word Bionics (also known as
only a few devices, perhaps as many as        biomimetics, biognosis, biomimicry, or
bionical creativity engineering) is the
application of biological methods and                         Fig.3.1 Normal eye
systems found in nature to the study and
design of engineering systems and
modern technology. The word 'bionic'
was coined by Jack E. Steele in1958,
possibly originating from the Greek word
"βίον", pronounced "bion", meaning "unit
of life" and the suffix -ic, meaning "like"
or "in the manner of", hence "like life".
Some dictionaries, however, explain the
word as being formed from "biology" +
"electronics".




BIONIC EYE:                                    Fig.3.2 Defective eye (Retinitis
                                               Pigmentosa)


        A visual prosthetic or bionic eye
is a form of neural prosthesis intended
to partially restore lost vision or amplify
existing vision. It usually takes the form
of an externally-worn camera that is
attached to a stimulator on the retina,
optic nerve, or in the visual cortex, in
order to produce perceptions in the visual
cortex.


3. BIONIC EYE IS FOR
                                                       Macular Degeneration is also a
WHOM:
                                               genetically related disease in which cones
                                               in Macula region degenerate, resulting in
       For those who are blind because
                                               loss or damage of central vision and this
of
                                               disease is very common among old
                                               people.
       1. Retinitis Pigmentosa
       2. Macular Degeneration.
                                                      Fig.3.3 Normal eye
        The following figures show
normal eye and the eye affected by
Retinitis Pigmentosa and Macular
Degeneration.

        Retinitis Pigmentosa is a
hereditary Genetic Disease which is the
degeneration of Peripheral Rods. The
disease gradually progresses towards
center of eye, and results in tunnel vision.
                                             grain-3 millimeters and allows users to
                                             perceive 10 degrees of visual field at a
                                             tim
                                             e.
                                             It's
                                             a
                                             flat
                                             rect
                                             ang
                                             le
                                             of
                                             pla
                                             stic
Fig.3.4 Defective eye (Macular               (ev
Degeneration)                                ent
                                             uall
                                             ya
                                             sili
                                             con
                                             ver
                                             sio
                                             n is
                                             has
                                             bee
                                             n developed) with one corner snipped off
                                             to create asymmetry so surgeons can
                                             orient it properly during implantation.
                                             One design includes an orchard of pillars:
                                             One side of each pillar is a light-sensing
                                             pixel and the other side is a cell-
        In the world, 1.5 million people     stimulating electrode. Pillar density
suffer from retinitis pigmentosa (RP), the   dictates image resolution, or visual
leading cause of inherited blindness. In     acuity. The strip of orchard across the top
the Western world, age-related macular       third of the chip is densely planted. The
degeneration (AMD) is the major cause
of vision loss in people over age 65, and
the issue is becoming more critical as the
population ages. Each year, 7, 00,000
people are diagnosed with AMD, with 10
percent becoming legally blind, defined
by 20/400 vision. Many AMD patients
retain some degree of peripheral vision.
        Currently, there is no effective
treatment for most patients with AMD
and RP but with the bionic eye; some of
the eyesight of the blind can be brought
back.

4. WHAT IS THE BIONIC EYE
MADE OF?
      The chip is the size of half a rice
strip in the middle is moderately dense,        sends its image of the flower to an
and the strip at the bottom is sparser still.   infrared LED-LCD screen mounted on
Dense electrodes lead to better image           the goggles. The transparent goggles
resolution but may inhibit the desirable        reflect an infrared image into the eye and
migration of retinal cells into voids near      onto the retinal chip.
electrodes, so the different electrode
densities of a current chip design allow                 Just as a person with normal
the researchers to explore parameters and       vision cannot see the infrared signal
come up with a chip that performs               coming out of a TV remote control, this
optimally. Another design-pore                  infrared flower image is also invisible to
electrodes-involves an array of cavities        normal photoreceptors. But for those
with stimulating electrodes located inside      sporting retinal implants, the infrared
each of them.                                   flower electrically stimulates the
         The chip will be placed right on       implant's array of photodiodes.
the retina replacing the defective rods and              The result ? They may not have to
cones                                           settle for merely smelling the roses."
(Photoreceptors)                                There are a lot more advantages:

                                                1.Very Early in the visual pathway
                                                2.No Batteries implanted within body
                                                3.No complicated surgical procedure
                                                4.Power Requirement - ¼ of milliwatt

                                                But there are a few problems with the
                                                chip "MADE OF SILICON". Silicon is
                                                toxic to the human body and reacts
                                                unfavourably with fluids

                                                in the eye. Furthermore, all of the
                                                nutrients feeding the eye flow from the
                                                back to the front. If a large, impervious
Figure 4: Designs of Bionic Eyes                structure [like the silicon detectors] in the
                                                eye is implanted, nutrients can't flow and
                                                the blockage of nutrients flow to the eye
                                                happens and the eye will atrophy.

5. HOW DOES THE SYSTEM HELPS                    AND THERE IS A SOLUTION TO THIS
                                                SERIOUS PROBLEM !!
TO SEE?



Let's take an example with viewing a                6.CERAMIC THIN FILM
flower.                                         MICRODETECTORS:

"First, light from the flower enters the
video camera. (Keep in mind that camera
technology is already pretty good at
adjusting contrast and other types of
image enhancement.) The video camera
then sends the image of the flower to the
wallet-sized computer for complex
processing. The processor then wirelessly
                                             7.DO BIONIC EYE HAVE ANY
                                             OTHER SPECIALITIES?

                                                     The arrays are stacked in a
                                             hexagonal structure mimicking the
                                             arrangement of rods and cones they are
                                             designed to replace.
                                                      The natural layout of the
                                             detectors solves another problem that
                                             plagued earlier silicon research: blockage
                                             of nutrient flow to the eye as the ceramic
                                             detector
        Figure 6: A schematic diagram of     Figure 7: These first-generation ceramic
the retina -- a light-sensitive layer that   thin film micro detectors, each about 30
covers 65% of the interior surface of the    microns in size, are attached to a polymer
eye                                          carrier, which image shows human cones
                                             5-10 microns in size in a hexagonal arrays
         These ceramic micro-detectors       helps surgeons handle them. The
are invented by The Space Vacuum             background are individual, five-micron
Epitaxy Center(SVEC) is a NASA-
sponsored Commercial Space Center                   .-size units(the exact size of
(CSC) at the University of Houston.          cones) that allow nutrients to flow around
         SVEC's ceramic detectors do not     them.
share the same problems with the silicon
detectors in toxicity to the human body
and unfavourable reactions with fluids in
the eye. Tests on the ceramic detectors
for biocompatibility, and they are totally   8.SO HOW ARE THEY IMPLANTED
stable. In other words, the detector does    INTO THE EYES?
not deteriorate and neither does the eye.
         These detectors are thin films,             As the detector is so small to
grown atom-by-atom and layer-by-layer        handle, the arrays are attached to a
on a background substrate -- a technique     polymer film one millimeter by one
called epitaxy."Well-ordered, 'epitaxally-   millimeter in size. A couple of weeks
grown' films have [the best] optical         after insertion into an eyeball, the
properties", said Dr. Alex Ignatiev, a       polymer film will simply dissolve leaving
professor at the University of Houston.      only the array behind. Clever isn't it? The
                                             new bionic eyes will surely be promising
                                             to the blind.


                                                    Hope that more and more blind
                                             people will be able to see the light again
                                             soon!!!!!
Fig. 8.1: How the Bionic eye implant
works?




                                       Fig.8.3:Bionic eye implanted!



Fig.8.2: Core view of Bionic eye
9.CONSTRUCTIONAL VIEW OF                      pigmentosa or age-related macular
BIONIC EYE:                                   degeneration. In these cases, the
                                              photoreceptor cells are dead, but other
         Scientists at the University of      nerve cells downstream of the
California, Berkeley, have given "blind"      photoreceptors are still alive. In
nerve cells the ability to detect light,      particular, retinal ganglion cells, which
paving the way for an innovative therapy      are the third cell in the path from
that could restore sight to those who have    photoreceptor to brain, could take over
lost it through disease.                      some of the functions of the
         A team lead by neurobiologist        photoreceptors if they could be
Richard H. Kramer, UC Berkeley                genetically engineered to respond to light.
professor of molecular and cell biology,
and Dirk Trauner, assistant professor of
chemistry, inserted a light-activated                   How well electrodes would work
switch into brain cells normally              depends on the density of the electrode
insensitive to light, enabling the            array and how well you can marry the
researchers to turn the cells on with green   electrodes with the neural elements
light and turn them off with ultraviolet      underneath.This approach is not a mere
light.                                        chip on the retina -- it may allow to
                                              cover the entire retina with light sensitive
                                              cells. If each nerve responds individually,
                                              one could do a very fine scan of the
                                              retinal field and create much, much better
                                              spatial resolution.

                                                       Current, admittedly early attempts
                                              at restoring sight with electrodes in the
                                              retinal ganglion cells, whose axons
                                              bundle together to form the optic nerve
                                              entering the brain, allow the patient to see
                                              little more than patches of light and dark,
                                              Kramer noted.
Fig.9.1: Potassium channels normally                     Trauner, Kramer and their team
open in response to a voltage difference      designed a way to re-engineer the
between the inside and outside of a nerve     potassium channel to respond to light
cell, letting potassium ions (K+) flow out    rather than voltage. To create this man-
to equalize the voltage and turn the cell     made channel and insert it into living
off. This channel has been broken, then       cells, they took a two-step approach.
re-engineered to open when hit with           First, they mutated the gene for the ion
ultraviolet light and close when hit with     channel -- using as their starting material
green light. The opening and closing is       the potassium channel found in fruit flies
achieved with a molecule that kinks and       -- so that, when expressed in a cell, the
unkinks in response to different              channel is broken and always stays open.
wavelengths of light. This photoswitch        They also added an extra molecule -- the
can be used to selectively silence nerve      amino acid cysteine -- to the channel
cells or to give the gift of "sight" to       protein so that, once the protein gets in
normally sightless organisms or cells.        place in the cell membrane, this molecule
                                              dangles off the outer surface of the cell
       This trick could potentially help      like a fish hook.
those who have lost the light-sensitive                 They then inserted the mutated
rods and cones in their eyes because of       potassium channel gene into cells from
nerve damage or diseases such as retinitis    the hippocampus of a rat -- cells that are
found inside the brain and never see the      Fig.10.1:Professor Minas Coroneos
light of day. To achieve this in their cell   holds a model of the human eye
culture experiment, they flooded the
culture with the mutated gene inside a                  The type of vision we think will
circular piece of DNA called a plasmid,       happen initially won’t be anything like
which cells readily take up. They checked     yours or my eyesight. It’s not going to be
to see how many of the hippocampus            normal vision. The current Cochlear
cells took up the gene by also washing        devices have about 30 electrodes.
the cells with a plasmid containing a gene    Imagine having 30 electrodes on the outer
for green fluorescent protein, which          wall of the eye, which in theory means
glows green when hit with UV light.           that if you turn them on at the same time,
Cells taking up one plasmid usually take      you will get 30 flashes of light. The idea
up other plasmids, and nearly all the cells   is that you will have a series of flashes
glowed green.                                 outlining objects.
           The second step was to wash the
cells with a chemically synthesized           11.BIONIC EYE AND ITS
switch that gloms onto the cysteine hook.     AVAILABILITY:
The photoswitch -- an azobenzene
compound -- was built like a drain plug                The bionic eye will be available
on a rigid tether, so that when the end of    in the next five years. Now that might
the tether binds to cysteine, the plug fits   sound like a long time but given that the
snugly into the potassium channel.            scientists have been working on this for
The chemical was also designed to be          only five years, and are half way through
sensitive to light -- when hit with long-     this cycle. Just to make it very plain - and
wavelength ultraviolet light (390             they have been very careful with any
nanometer wavelength), the tether kinks       publicity because they don’t want people
and shortens, pulling the plug and letting    to think that they are about to have a
potassium out of the cell. Green light        product- what they have achieved is an
(500 nanometer wavelength), on the other      important step forward.They took a
hand, makes the chemical tether straight      slightly different approach. Normally,
again, replugging the channel pore. They      most of the groups that are working on
refer to the altered channel as a synthetic   the retina have put electrodes on it. The
photoisomerizable azobenzene-regulated        retina is like a film in a camera. It has a
K (SPARK) channel, where K is the             layer of cells that detect light and turn
chemical signal for potassium.                light into electrical signals. Those signals
                                              go to nerves that join up and form the
10.IS THE BIONIC EYE THE                      optic nerve. Because the retina is very
ULTIMATE SOLUTION FOR BLIND                   delicate and also because you have to
                                              open the eye, that approach involves
                                              some risk.
                                                       Just imagine what might happen
                                              to someone with pieces of metal attached
                                              to their retina if they jump on a
                                              trampoline. The approach they took was
                                              to put electrodes on the outer wall of the
                                              eye and increase the current, so it still
                                              stimulates the retina. Because of this,
                                              they do not have to open the eye. They
                                              think that might be a more stable and
                                              safer system long term. So earlier this
PEOPLE?                                       year, They put some electrodes on the
                                              outer wall of the eye of a patient, we
stimulated those electrodes and the           were no noticeable changes to anatomical
patient was able to see flashes of light.     integrity.

                                                      The implants were successful in
12.ONGOING PROJECTS:                          producing evoked cortical potentials in
                                              half of the animals tested. The thresholds
12.1. MICROSYSTEM-BASED VISUAL                identified in this study were similar to
PROSTHESIS (MVIP):
                                              those required in epiretinal stimulation.
        Designed by Claude Veraart at the     12.4. ARTIFICIAL SILICON RETINA
                                              (ASR):
University of Louvain, this is a spiral
                                                      The brothers Alan Chow and
cuff electrode around the optic nerve at
                                              Vincent Chow have developed a
the back of the eye. It is connected to a
                                              microchip containing 3500 solar cells,
stimulator implanted in a small
                                              which detect light and convert it into
depression in the skull. The stimulator
                                              electrical impulses, which stimulate
receives signals from an externally-worn
                                              healthy retinal ganglion cells. The ASR
camera, which are translated into
                                              requires no externally-worn devices.
electrical signals that stimulate the optic
nerve directly.                               12.5. OPTOELECTRONIC RETINAL
                                              PROSTHESIS:
12.2. IMPLANTABLE MINIATURE                           Daniel Palanker and his group at
TELESCOPE:                                    Stanford University have developed an
                                              optoelectronic system for visual
        Although not truly an active
                                              prosthesis that includes a subretinal
prosthesis, an Implantable Miniature
                                              photodiode array and an infrared image
Telescope is one type of visual implant
                                              projection system mounted on video
that has met with some success in the
                                              goggles. Information from the video
treatment of end-stage age-related
                                              camera is processed in a pocket PC and
macular degeneration. This type of
                                              displayed on pulsed near-infrared (IR,
device is implanted in the eye's posterior
                                              850-900 nm) video goggles. IR image is
chamber and works by increasing (by
                                              projected onto the retina via natural eye
about three times) the size of the image
                                              optics, and activates photodiodes in the
projected onto the retina in order to
                                              subretinal implant that convert light into
overcome a centrally-located scotoma or
                                              pulsed bi-phasic electric current in each
blind spot.

12.3. MPDA PROJECT:
         The chip is located behind the
retina and utilizes microphotodiode
arrays (MPDA) which collect incident
light and transform it into electrical
current stimulating the retinal ganglion
cells. As natural photoreceptors are far
more efficient than photodiodes, visible
light is not powerful enough to stimulate
the MPDA. Therefore, an external power
supply is used to enhance the stimulation     pixel. Current can be further increased by
current. The German team commenced in         approximately an order of magnitude
vivo experiments in 2000, when evoked         using a common bias voltage provided by
cortical potentials were measured from        a radiofrequency-driven implantable
micropigs and rabbits. At 14 months post      power supply .Close proximity between
implantation, the implant and retina          electrodes and neural cells necessary for
surrounding it were examined and there        high resolution stimulation can be
achieved utilizing effect of retinal        13.1.1.BIONICEYE MAGNIFIES
migration.                                  ANYTHING 200 TIMES:
                                            Fig.13.3: Feather Magnified
12.6. THE VIRTUAL RETINAL
DISPLAY (VRD):

        Laser-based system for projecting
an image directly onto the retina. This
could be useful for enhancing normal
vision or bypassing an occlusion such as
a cataract, or a damaged cornea.

13.APPLICATIONS OF BIONIC
EYE:

13.1 EYECLOP BIONIC EYE:

Giant eyeball magnifies 200x:               Fig.13.4: Table Salt Magnified



                                                    The Bionic Eye comes with a
                                            viewing tube, viewing dish and the base
                                            for hands-free use, while you must
                                            provide it the 5 AA batteries.
                                                     For its capability to show table
                                            salt looking like blocks of ice, fine hair
                                            looking like twisted rope or your skin
                                            looking like an alien one, the device has
Fig.13.1: Eyeclops Bionic eye               won many awards such as Parents Choice
                                            Best Toy Award, Parents Magazine Best
                                            Toy Award, Children’s Technology
                                            Review, Editor’s Choice Award, Toy
                                            Insider Hot 20 Toys, and ToysRUs
                                            Fabulous 15 Toys.
                                                    To use the Bionic Eye, it is
                                            enough to plug it into the TV and turn it
                                            on.
                                            You’ll need no additional software to run
                                            or special system requirements to meet,
                                            and
                                            you can observe the details of any object
                                            or animal from your dog to your carpet
                                            and the
                                            Liquid in your glass.
Fig. 13.2
                                            13.1.2. PRODUCT FEATURES:
“EYECLOPS BIONIC EYE” a handled                    View virtually any item at 200
contraption that supposedly magnifies            times the regular size on any TV
whatever it sees on a order of 200x and          screen
displays it on whatever TV it is plugged
                                                  Plugs directly into your TV; No
into.
                                                 software to install
       Includes observation dish and        create a new cornea through technology.
     tube to view liquids, salt, bugs, etc   The cornea allows light into the interior
     and base for hands-free use.            of the eye.
                                             Dobelle is using a digital video camera
      3 built-in LED lights illuminate
                                             mounted on glasses to capture an image
     any object. BONUS - EXTRA
                                             and send it to a small computer on the
     VIEWING STAND
                                             patient's belt: The images are processed
                                             and sent to electrodes implanted in the
 13.2. EYECLOP BIONICAM:                     patient's visual cortex. The electrodes
                                             stimulate the brain, producing a pattern of
                                             bright spots that form an image.

                                             14.1.1 IMPLEMENTATION:

                                             A Canadian farmer and father of eight,
                                             Jens lost his sight 18 years ago in an
                                             accident. Now he's able to navigate
                                             through rooms, find doors and even drive
                                             a car to some degree.
                                             "I was able to very carefully drive and
                                             look from my left side to my right side,
                                             making sure I was between this row of
                                             trees on the right and the building on my
                                             left," he says. "When I got near any
                                             obstruction, I would see that there was an
                                             obstruction. I would also see the lack of
                                             obstructions, knowing I wasn't going to
                                             run over anybody .It was a very nice
                                             feeling."
                                                     The black and white image Jens
                                             sees is not solid, but resembles a dot
The wireless “EYECLOPS BIONICAM”             matrix pattern. It's like looking at a sport
has doubled the top magnification to         scoreboard with different light patterns
400x and has its own built-in color LCD      illuminated to show different scores.
instead of requiring a computer screen for
viewing .It also comes with a USB flash
                                             14.1.2 COST:
drive presumably to record and transfer
whatever images are projected on                  The miniaturization of equipment and
it,according to device.                      more powerful computers have made this
                                             artificial vision possible, but it's not
14.RESEARCH:
                                             cheap: The operation, equipment and
14.1. DOBELLE INSTITUTE:                     necessary training cost $70,000 per
                                             patient.
         Any scientific advance would
                                             14.2. NASA:
have broad implications. According to
statistics from Research to Prevent                  NASA hopes to begin human
Blindness, Inc., 1.1 million people in the   testing this year on ceramic detectors that
United States are legally blind, while       could be implanted in the retina to take
worldwide 42 million people are without      over the job of damaged retinal cells. And
sight.                                       the Office of Naval Research goes one
         The Dobelle Institute is among      step further -- it says it is on the way to
several institutions trying in essence to
developing a chip that would replicate the             Fig.14.1:Contact lens for
entire nerve center of the retina.              superhuman vision
                                                       The device to make this happen
14.3. OPTOBIONICS CORPORATION:                  may be familiar. Engineers at the
                                                University of
         Optobionics Corporation of
Wheaton, Illinois, says six blind or nearly
blind people can now see light and some                  Washington have for the first time
can see shapes after having the company's       used manufacturing techniques at
artificial retina implanted. Optobionics        microscopic scales to combine a flexible,
hopes to have the artificial retina on the      biologically safe contact lens with an
market in five years, but critics say it will   imprinted electronic circuit and lights.
take years of independent testing to prove      There are many possible uses for virtual
it helps the blind.                             displays. Drivers or pilots could see a
                                                vehicle's speed projected onto the
14.3.1 SILICON CHIPS IMPLANTED INTO
THE EYES OF THREE PATIENTS TO                   windshield.
TREAT BLINDNESS:                                         Video-game companies could use
                                                the contact lenses to completely immerse
        Three people who had lost most          players in a virtual world without
of their vision from retinitis pigmentosa -     restricting their range of motion. And for
a condition that causes degeneration of         communications, people on the go could
the retina, received similar type chips.        surf the Internet on a midair virtual
The chips are 2 mm in diameter, about           display screen that only they would be
the width of the head of a pin, and a           able to see.
thousandth of an inch thick - thinner than               The prototype device contains an
a sheet of paper. Each chip contains            electric circuit as well as red light-
approximately 3500 microscopic solar            emitting diodes for a display, though it
cells designed to stimulate remaining           does not yet light up. The lenses were
retinal cells from underneath the retina in     tested on rabbits for up to 20 minutes and
a pattern resembling the light images           the animals showed no adverse effects.
focused on the chip. The chips are                        Ideally, installing or removing
completely self-contained and receive           the bionic eye would be as easy as
their power entirely from the light that        popping a contact lens in or out, and once
enters the eye - requiring no wires or          installed the wearer would barely know
batteries.                                      the gadget was there, Parviz said.
                                                Building the lenses was a challenge
14.3.1.1       Contact lenses with              because materials that are safe for use in
       circuits, lights a possible              the body, such as the flexible organic
       platform for superhuman                  materials used in contact lenses, are
       vision:                                  delicate. Manufacturing electrical
                                                circuits, however, involves inorganic
                                                materials, scorching temperatures and
                                                toxic chemicals. Researchers built the
                                                circuits from layers of metal only a few
                                                nanometers thick, about one thousandth
                                                the width of a human hair, and
                                                constructed light-emitting diodes one
                                                third of a millimeter across. They then
                                                sprinkled the grayish powder of electrical
                                                components onto a sheet of flexible
                                                plastic. The shape of each tiny component
                                                dictates which piece it can attach to, a
microfabrication technique known as           designed lenses, on the other hand, have
self-assembly. Capillary forces – the         irregular front surface profiles designed
same type of forces that make water           to correct for specific aberrations of the
move up a plant's roots, and that cause the   cornea and crystalline lens. The scientists
edge of a glass of water to curve upward      designed the front profiles by measuring
– pull the pieces into position.              with wavefront sensors exactly how light
                                              enters the subjects’ eyes through the
14.4. KERATONIC EYE:                          misshapen cornea. In collaboration with
                                              Bausch & Lomb, an oscillating tool lathe
        Keratoconic eyes are rare but         sculpted the front surface of the lens.
disabling. From the side, the eyes look                Keeping the lenses exactly in
more pointed or cone-shaped than round.       place is still a challenge, as blinking
The apex shift from visual axis in the        notoriously shifts contacts. The scientists
cornea causes people with the condition       used existing stabilizing techniques, such
to see halos and double and triple images.    as making the lenses bottom-heavy, to
About 1 in 2,000 people suffer from the       coax them into correct orientation.
disease, usually in both “The condition                With all the new research
shows up in a relatively small population,    developments coming into view, one can
but it causes huge optical problems,” says    catch a glimpse of the future of blindness.
Geunyoung Yoon, assistant professor in
the Departments of Ophthalmology and
Biomedical Engineering, the Center for
Visual Science, and the Institute of
Optics. “These people have problems so
severe, they can’t tolerate glasses. They
can’t take laser vision correction because
they have a very thin cornea around the
apex, so it’s not an option. The only
available treatment is to wear hard
contact
lenses or corneal transplant with a
donored cornea if the disease is severe.
And with the corneal transplant, there is a
rejection rate.”
        All three subjects reported their
vision significantly improved with the
custom-designed soft contact lenses.
        The scientists tested several
designs of custom lenses on the subjects’
eyes for both high-contrast and low-
contrast visual acuity. They compared
vision with the custom-designed soft
lenses to vision with conventional lenses
and rigid gas permeable lenses, or hard
contact lenses. Corrections with the
custom lenses resulted in an average
improvement of 2.1 lines in visual acuity,
or from 20/48 to 20/29, over the use of
the conventional defocus and astigmatism
corrections alone. Conventional soft
contact lenses do not work for
keratoconic eyes, as they merely conform
to the conical cornea shape. The custom-
15. The Road to Artifical Vision               17.REFERENCES:
                                                  1. www.way2students.com
1929
German neurologist Otfird Foerster
electrically stimulates the visual cortex of
a human volunteer's brain causing his
subject to “see” small points of light.
1968
Giles S. Brindley of the University of
Cambridge implants 80 electrodes under
the scalp of a 52-year-old woman who
had gone blind. When he applies
electricity, the woman sees spots of light.
2004
Arman Tanguay and his colleague Noelle
Stiles conduct the first experiment to
implant a digital camera in an eye,
replacing a dog's natural lens with a glass
lens and a sensor.
2010
USC Researchers conduct the first human
trial of a implantable digital camera
connected to a 256-electrode retinal
implant.
2014
The introduction of a 1,000-electrode
implant allows blind volunteers to
recognize faces and read half-inch type
for the first time.




16.DEMERITS:

Dr. Bill Dobelle, of the Dobelle Institute,
says the technology has broad potential.
"It may not work for people blinded as
children or as infants, because the visual
cortex did not develop normally.”

				
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