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					BIONIC EYE
                                              BIONICS:
ABSTRACT:
                                                       The word Bionics (also known as
Imagine by placing VLSI circuits in the       biomimetics, biognosis, biomimicry, or
eye of a person with a defective eye, we      bionical creativity engineering) is the
can increase the efficiency and improve       application of biological methods and
the sight of that.Appropriately saying to     systems found in nature to the study and
create sight to the blind using VLSI          design of engineering systems and
designs                                       modern technology. The word 'bionic'
        Very-large-scale integration          was coined by Jack E. Steele in1958,
(VLSI) is the process of creating             possibly originating from the Greek word
integrated circuits by combining              "βίον", pronounced "bion", meaning "unit
thousands of transistor-based circuits into   of life" and the suffix -ic, meaning "like"
a single chip. VLSI began in the 1970s        or "in the manner of", hence "like life".
when complex semiconductor and                Some dictionaries, however, explain the
communication technologies were being         word as being formed from "biology" +
developed. The microprocessor is a VLSI       "electronics".
device. The term is no longer as common
as it once was, as chips have increased in
complexity into the hundreds of millions      BIONIC EYE:
of transistors.
        The first integrated circuits held            A visual prosthetic or bionic eye
only a few devices, perhaps as many as        is a form of neural prosthesis intended
ten diodes, transistors, resistors and        to partially restore lost vision or amplify
capacitors, making it possible to fabricate   existing vision. It usually takes the form
one or more logic gates on a single           of an externally-worn camera that is
device. Now known retrospectively as          attached to a stimulator on the retina,
"small-scale integration" (SSI),              optic nerve, or in the visual cortex, in
improvements in technique led to devices      order to produce perceptions in the visual
with hundreds of logic gates, known as        cortex.
large-scale integration (LSI), i.e. systems
with at least a thousand logic gates.
Current technology has moved far past
this mark and today's microprocessors
have many millions of gates and
hundreds of millions of individual
transistor
3.BIONIC EYE IS FOR WHOM:                              Macular Degeneration is also a
                                               genetically related disease in which cones
       For those who are blind because         in Macula region degenerate, resulting in
of                                             loss or damage of central vision and this
                                               disease is very common among old
       1.Retinitis Pigmentosa                  people.
       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.


               Fig.3.1 Normal eye

                                               Fig.3.4 Defective eye (Macular
                                               Degeneration)




Fig.3.2 Defective eye (Retinitis
Pigmentosa)
                                                       In the world, 1.5 million people
                                               suffer from retinitis pigmentosa (RP), the
                                               leading cause of inherited blindness. In
                                               the Western world, age-related macular
                                               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
grain-3 millimeters and allows users to
perceive 10 degrees of visual field at a
time. It's a flat rectangle of plastic
(eventually a silicon version is has been
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-stimulating
electrode. Pillar density dictates image
resolution, or visual acuity. The strip of
orchard across the top third of the chip is
densely planted. The strip in the middle is
                                               Figure 4: Designs of Bionic Eyes
moderately dense, and the strip at the
bottom is sparser still. Dense electrodes
lead to better image resolution but may
inhibit the desirable migration of retinal
cells into voids near electrodes, so the
                                               5.HOW DOES THE SYSTEM HELPS
different electrode densities of a current
                                               TO SEE?
chip design allow the researchers to
explore parameters and come up with a
chip that performs optimally. Another
design-pore electrodes-involves an array
of cavities with stimulating electrodes
located inside each of them.
         The chip will be placed right on
the retina replacing the defective rods and
cones
(photoreceptors)
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
sends its image of the flower to an
infrared LED-LCD screen mounted on
the goggles. The transparent goggles
reflect an infrared image into the eye and
onto the retinal chip.
                                                        Figure 6: A schematic diagram of
         Just as a person with normal           the retina -- a light-sensitive layer that
vision cannot see the infrared signal           covers 65% of the interior surface of the
coming out of a TV remote control, this         eye
infrared flower image is also invisible to
normal photoreceptors. But for those                     These ceramic micro-detectors
sporting retinal implants, the infrared         are invented by The Space Vacuum
flower electrically stimulates the              Epitaxy Center(SVEC) is a NASA-
implant's array of photodiodes.                 sponsored Commercial Space Center
         The result ? They may not have to      (CSC) at the University of Houston.
settle for merely smelling the roses."                   SVEC's ceramic detectors do not
There are a lot more advantages:                share the same problems with the silicon
                                                detectors in toxicity to the human body
1.Very Early in the visual pathway              and unfavourable reactions with fluids in
2.No Batteries implanted within body            the eye. Tests on the ceramic detectors
3.No complicated surgical procedure             for biocompatibility, and they are totally
4.Power Requirement - ¼ of milliwatt            stable. In other words, the detector does
                                                not deteriorate and neither does the eye.
But there are a few problems with the                    These detectors are thin films,
chip "MADE OF SILICON". Silicon is              grown atom-by-atom and layer-by-layer
toxic to the human body and reacts              on a background substrate -- a technique
unfavourably with fluids                        called epitaxy."Well-ordered, 'epitaxally-
                                                grown' films have [the best] optical
in the eye. Furthermore, all of the             properties", said Dr. Alex Ignatiev, a
nutrients feeding the eye flow from the         professor at the University of Houston.
back to the front. If a large, impervious
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.

AND THERE IS A SOLUTION TO THIS
SERIOUS PROBLEM !!
                                             cones) that allow nutrients to flow around
7.DO BIONIC EYE HAVE ANY                     them.
OTHER SPECIALITIES?

        The arrays are stacked in a
hexagonal structure mimicking the
arrangement of rods and cones they are       8.SO HOW ARE THEY IMPLANTED
designed to replace.                         INTO THE EYES?
         The natural layout of the
detectors solves another problem that                As the detector is so small to
plagued earlier silicon research: blockage   handle, the arrays are attached to a
of nutrient flow to the eye as the ceramic   polymer film one millimeter by one
detector                                     millimeter in size. A couple of weeks
Figure 7: These first-generation ceramic     after insertion into an eyeball, the
thin film microdetectors, each about 30      polymer film will simply dissolve leaving
microns in size, are attached to a polymer   only the array behind. Clever isn't it? The
carrier, which image shows human cones       new bionic eyes will surely be promising
5-10 microns in size in a hexagonal arrays   to the blind.
helps surgeons handle them. The
background are individual, five-micron
                                                    Hope that more and more blind
       .-size units   (the exact size of     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
switch into brain cells normally                        How well electrodes would work
insensitive to light, enabling the            depends on the density of the electrode
researchers to turn the cells on with green   array and how well you can marry the
light and turn them off with ultraviolet      electrodes with the neural elements
light.                                        underneath.This approach is not a mere
                                              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,
Fig.9.1: Potassium channels normally          Kramer noted.
open in response to a voltage difference                 Trauner, Kramer and their team
between the inside and outside of a nerve     designed a way to re-engineer the
cell, letting potassium ions (K+) flow out    potassium channel to respond to light
to equalize the voltage and turn the cell     rather than voltage. To create this man-
off. This channel has been broken, then       made channel and insert it into living
re-engineered to open when hit with           cells, they took a two-step approach.
ultraviolet light and close when hit with     First, they mutated the gene for the ion
green light. The opening and closing is       channel -- using as their starting material
achieved with a molecule that kinks and       the potassium channel found in fruit flies
unkinks in response to different              -- so that, when expressed in a cell, the
wavelengths of light. This photoswitch        channel is broken and always stays open.
can be used to selectively silence nerve      They also added an extra molecule -- the
cells or to give the gift of "sight" to       amino acid cysteine -- to the channel
normally sightless organisms or cells.        protein so that, once the protein gets in
                                              place in the cell membrane, this molecule
       This trick could potentially help      dangles off the outer surface of the cell
those who have lost the light-sensitive       like a fish hook.
rods and cones in their eyes because of                 They then inserted the mutated
nerve damage or diseases such as retinitis    potassium channel gene into cells from
the hippocampus of a rat -- cells that are    Fig.10.1:Professor Minas Coroneos
found inside the brain and never see the      holds a model of the human eye
light of day. To achieve this in their cell
culture experiment, they flooded the                    The type of vision we think will
culture with the mutated gene inside a        happen initially won’t be anything like
circular piece of DNA called a plasmid,       yours or my eyesight. It’s not going to be
which cells readily take up. They checked     normal vision. The current Cochlear
to see how many of the hippocampus            devices have about 30 electrodes.
cells took up the gene by also washing        Imagine having 30 electrodes on the outer
the cells with a plasmid containing a gene    wall of the eye, which in theory means
for green fluorescent protein, which          that if you turn them on at the same time,
glows green when hit with UV light.           you will get 30 flashes of light. The idea
Cells taking up one plasmid usually take      is that you will have a series of flashes
up other plasmids, and nearly all the cells   outlining objects.
glowed green.
           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
PEOPLE?                                       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
                                              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
cuff electrode around the optic nerve at              The brothers Alan Chow and
the back of the eye. It is connected to a     Vincent Chow have developed a
stimulator implanted in a small               microchip containing 3500 solar cells,
depression in the skull. The stimulator       which detect light and convert it into
receives signals from an externally-worn      electrical impulses, which stimulate
camera, which are translated into             healthy retinal ganglion cells. The ASR
electrical signals that stimulate the optic   requires no externally-worn devices.
nerve directly.
                                              12.5. OPTOELECTRONIC RETINAL
12.2. IMPLANTABLE MINIATURE                   PROSTHESIS:
TELESCOPE:
                                                      Daniel Palanker and his group at
        Although not truly an active          Stanford University have developed an
prosthesis, an Implantable Miniature          optoelectronic system for visual
Telescope is one type of visual implant       prosthesis that includes a subretinal
that has met with some success in the         photodiode array and an infrared image
treatment of end-stage age-related            projection system mounted on video
macular degeneration. This type of            goggles. Information from the video
device is implanted in the eye's posterior    camera is processed in a pocket PC and
chamber and works by increasing (by           displayed on pulsed near-infrared (IR,
about three times) the size of the image      850-900 nm) video goggles. IR image is
projected onto the retina in order to         projected onto the retina via natural eye
overcome a centrally-located scotoma or       optics, and activates photodiodes in the
blind spot.                                   subretinal implant that convert light into
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        pulsed bi-phasic electric current in each
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
can see shapes after having the company's                Washington have for the first time
artificial retina implanted. Optobionics        used manufacturing techniques at
hopes to have the artificial retina on the      microscopic scales to combine a flexible,
market in five years, but critics say it will   biologically safe contact lens with an
take years of independent testing to prove      imprinted electronic circuit and lights.
it helps the blind.                             There are many possible uses for virtual
                                                displays. Drivers or pilots could see a
14.3.1 SILICON CHIPS IMPLANTED INTO
THE EYES OF THREE PATIENTS TO                   vehicle's speed projected onto the
TREAT BLINDNESS:                                windshield.
                                                         Video-game companies could use
        Three people who had lost most          the contact lenses to completely immerse
of their vision from retinitis pigmentosa -     players in a virtual world without
a condition that causes degeneration of         restricting their range of motion. And for
the retina, received similar type chips.        communications, people on the go could
The chips are 2 mm in diameter, about           surf the Internet on a midair virtual
the width of the head of a pin, and a           display screen that only they would be
thousandth of an inch thick - thinner than      able to see.
a sheet of paper. Each chip contains                     The prototype device contains an
approximately 3500 microscopic solar            electric circuit as well as red light-
cells designed to stimulate remaining           emitting diodes for a display, though it
retinal cells from underneath the retina in     does not yet light up. The lenses were
a pattern resembling the light images           tested on rabbits for up to 20 minutes and
focused on the chip. The chips are              the animals showed no adverse effects.
completely self-contained and receive                     Ideally, installing or removing
their power entirely from the light that        the bionic eye would be as easy as
enters the eye - requiring no wires or          popping a contact lens in or out, and once
batteries.                                      installed the wearer would barely know
                                                the gadget was there, Parviz said.
14.3.1.1       Contact lenses with              Building the lenses was a challenge
       circuits, lights a possible              because materials that are safe for use in
       platform for superhuman                  the body, such as the flexible organic
       vision:                                  materials used in contact lenses, are
                                                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      to the conical cornea shape. The custom-
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
15.The Road to Artifical Vision                17.REFERENCES:

1929                                             1.   www.google.com
German neurologist Otfird Foerster               2.   www.optobionics.com
electrically stimulates the visual cortex of     3.   www.wikipedia.com
a human volunteer's brain causing his            4.   www.science.nasa.gov
subject to “see” small points of light.          5.   www.physorg.com
1968                                             6.   www.howstuffworks.com
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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posted:5/29/2012
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