1

INTRODUCTION

An ocular prosthesis or artificial eye is a type of craniofacial prosthesis that replaces an absent

Natural eye following an enucleating, evisceration, or orbital exenterating. The prosthesis fits

Over an orbital implant and under the eyelids. Belonging to the community of engineers there is

no frontier that we cannot conquer. If scientists give birth to ideas, then it is we engineers who

put life into those ideas. Today, we talk of artificial intelligence that has created waves of interest

in the field of robotics. When this has been possible, then there is a possibility for artificial

vision. `Bionic eye’ also called a Bio Electronic eye, is the electronic device that replaces

functionality of a part or whole of the eye. It is still at a very early stage in its development, but if

successful, it could restore vision to people who have lost sight during their lifetime. This

technology can add life to their visionless eyes [1].

A bionic eye works by stimulating nerves, which are activated by electrical impulses. In this case

the patient has a small device implanted into the body that can receive radio signals and transmit

those signals to brain through nerves and can interpret the image. One of the most dramatic

applications of bionics is the creation of artificial eyes. Early efforts used silicon-based photo

detectors, but silicon is toxic to the human body and reacts unfavorably with fluids in the eye.

Now, scientists at the Space Vacuum Epitaxial Centre (SVEC) based at the University of

Houston, Texas, are using a new material they have developed, tiny ceramic photocells that

could detect incoming light and so repair malfunctioning human eyes [2].

`Bionic eye,' also called a Bio Electronic eye, is the electronic device that replaces functionality

of a part or whole of the eye. It is still at a very early stage in its development, but if successful,

it could restore vision to people who have lost sight during their lifetime. A bionic eye work by

stimulating nerves, which are activated by electrical impulses. In this case the patient has a small

device implanted into the body that can receive radio signals and transmit those signals to nerves.

One of the most dramatic applications of bionics is the creation of artificial eyes. Early efforts

used silicon-based photo detectors, but silicon is toxic to the human body and reacts unfavorably

with fluids in the eye. Now, scientists at the Space Vacuum Epitaxial Centre (SVEC) based at the

University of Houston, Texas, are using a new material they developed, tiny ceramic photocells

that could detect incoming light and so ‘repair’ malfunctioning human eyes

Today, high-tech resources in microelectronics, Optoelectronic, computer science, biomedical

2

engineering and also in vitreo retinal surgery are working together to realize a device for the

Electrical stimulation of the visual system. Artificial Eye, which works through retinal implants,

could restore sight to millions of people around the world who suffer from degenerative eye

diseases. This technology is still in its infancy, but has progressed to human trials. This report

aims to present a brief overview about the basic aspects of this technology and where it’s headed

prior to World War II, ocular prosthetics were made of specialized blown glass that collapsed to

Form a concave shape. During and after World War II this glass became increasing difficult to

Obtain. Soon, acrylic and other plastic polymers were being used for many of the uses previously

Exclusive to glass. An exciting use of this new material was for artificial eyes, or ocular

prosthetics. Acrylic revolutionized the art and process of making ocular prosthetics. In

comparison to glass, acrylic provided better comfort and fit. Glass artificial eyes frequently

needed replacing and broke easily. Acrylic improved the techniques for making artificial eyes

Such as impression molding, blending and allowed for easier changes in shape, color or size of

an ocular prosthesis.

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LITERATURE SURVEY

1. Tillman, Walter. An Eye for an Eye, a Guide for the Artificial Eye Wearer. F.A.S.O.,

1987.

2. Johnson, R. Colin. "Joint 'biochip' project eyes artificial retina," Electronic Engineering

Times, September 18, 1995.

3. Munro, Margaret. "Building a better eyeball," Montreal Gazette, April 19, 1995.

4. American Academy of Ophthalmology, 655 Beach St., San Francisco, CA 94109, 415-

561-8500

5. Biomedical Engineering McGraw-Hill: New York, Chicago, San Francisco, Lisbon,

London, Madrid, Mexico City, Milan, New Delhi, San Juan, Seoul, Singapore, Sydney,

Toronto 2003 The McGraw-Hill Companies, Inc.

6. Humayun MS, de Juan E Jr., Dagnelie G, et al. Visual perception elicited by electrical

stimulation of retina in blind humans. Archives of Ophthalmology; vol 114.

7. “Artificial Vision for the Blind by Connecting a Television Camera to the Brain" ASAIO

Journal 2000

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1. “History of Artificial Eyes”

1.1 Background

Prior to World War II, ocular prosthetics were made of specialized blown glass that collapsed toForm a concave shape. During and after World War II this glass became increasing difficult to

Obtain. Soon, acrylic and other plastic polymers were being used for many of the uses previously

Exclusive to glass. An exciting use of this new material was for artificial eyes, or ocular

prosthetics. Acrylic revolutionized the art and process of making ocular prosthetics. In

comparison to glass, acrylic provided better comfort and fit. Glass artificial eyes frequently

needed replacing and broke easily. Acrylic improved the techniques for making artificial eyes

Such as impression molding, blending and allowed for easier changes in shape, color or size of

an Ocular prosthesis. An artificial eye is a replacement for a natural eye lost because of injury or

disease. Although

The replacement cannot provide sight, it fills the cavity of the eye socket and serves as a

Cosmetic enhancement. Before the availability of artificial eyes, a person who lost an eye usually

wore a patch. An artificial eye can be attached to muscles in the socket to provide eye

Movement. Today, most artificial eyes are made of plastic, with an average life of about 10

years. Children require more frequent replacement of the prosthesis due to rapid growth changes.

As many as four or five prostheses may be required from infancy to adulthood. There are two

key steps in replacing a damaged or diseased eye. First, an ophthalmologist or eye surgeon must

remove the natural eye. There are two types of operations. The enucleating removes the eyeball

by severing the muscles, which are connected to the sclera (white of eyeball). The surgeon then

cuts the optic nerve and removes the eye from the socket. An implant is then placed into the

socket to restore lost volume and to give the artificial eye some movement, and the wound is

then closed. With evisceration, the contents of the eyeball are removed. In this operation, the

surgeon makes an incision around the iris and then removes the contents of the eyeball. A ball

made of some inert material such as plastic, glass, or silicone is then placed inside the eyeball,

and the wound is closed.

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1.2. History

Early artificial eye makers may not have been creating prostheses at all, but rather decorations

For religious and aesthetic purposes. In the millennia B.C., the people of Babylon, Jericho,

Egypt, China, and the Aegean area all had highly developed arts and a belief in the afterlife.

Radiographs of mummies and tombs have revealed numerous artificial eyes made of silver, gold,

rock crystal, lapis lazuli, shell, marble, enamel, or glass. The Aztec and Inca also used artificial

eyes for similar reasons. The skill of the Egyptian artists was so great that they were probably

asked to create artificial eyes for human use, especially if the afflicted were royalty. In 1579, the

Venetians invented the first prosthesis to be worn behind the eyelids. These artificial eyes were

very thin shells of glass, and therefore, did not restore the lost volume of an atrophied or missing

eyeball. Because the edges were sharp and uncomfortable, the wearers had to remove the eyes at

night in order to get relief from discomfort and to avoid breakage. After the invention of this

glass shell prosthesis, there were no significant advances in artificial eyes until the nineteenth

century. In the early 1800s, a German glassblower by the name of Ludwig Muller-Uri, who made

life-like eyes for dolls, developed a glass eye for his son. Though In 1880, Dutch eye surgeon

Hermann Smelled developed the Reform eye design. This design was a thicker, hollow glass

prosthesis with rounded edges. The increase in thickness restored most of the lost volume of the

eye and the rounded edges gave the patient much more comfort. Germany became the center for

manufacturing glass artificial eyes. Several years later in 1884, a glass sphere was implanted for

the first time in the scleral cavity (the hollowed out interior of the white of the eyeball) after

evisceration. An English doctor, Phillip Henry Mules, used the implant to restore lost volume

and to give the prosthesis some movement. The sphere implant was subsequently adapted for the

enucleated socket as well. Many materials such as bone, sponge, fat, and precious metals have

been used for implants since then, but 100 years later, the Mules sphere is still used in the

majority of cases. Eye sockets with spheres within the scleral cavity following evisceration

continue to result in excellent cosmetic results. For the enucleated socket another solution had to

be found. During World War II, the glass eyes from Germany were unavailable, and therefore

During World War II, the glass eyes from Germany were unavailable, and therefore, the United

States had to find an alternate material. In 1943, the U.S. Army dental technicians made the

First plastic artificial eye.

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2. “SYSTEM OVERVIEW”

2.1 Human Eye

Fig.2.1: Human Eye

We are able to see because light from an object can move through space and reach our eyes.

Once light reaches our eyes, signals are sent to our brain, and our brain deciphers the information

in order to detect the appearance, location and movement of the objects we are sighting at. The

internal working of eye is as follows [3], scattered light from the object enters through the

cornea.

1. The light is projected onto the retina.

2. The retina sends messages to the brain through the optic nerve.

3. The brain interprets what the object is.

2.2 Human Eye Conditions

The purpose of this section is to provide some background on human eye conditions that can lead

to vision loss and eye removal. The journey that leads one to our office is often not a pleasant

One. We feel quite privileged to be involved in the restoration and "return to normalcy" of our

Patients. We hope this information will be helpful. The various sections we cover are:

Anatomy of the eye

3 types of eye removal

Orbital eye implants

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Possible conditions leading to an artificial eye

Possible conditions leading to a scleral shell

Eye care specialists

Leading causes of eye loss in children

Fig.2.2: Anatomy of the eye

The choroid, which carries blood vessels, is the inner coat between the sclera and the

retina.

The conjunctiva is a clear membrane covering the white of the eye (sclera).

The cornea is a clear, transparent portion of the outer coat of the eyeball through which

light passes to the lens.

The iris gives our eyes color and it functions like the aperture on a camera, enlarging in

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Fig.2.3: Internal Structure of Human Eye

The eyeball is set in a protective cone-shaped cavity in the skull called the orbit or socket and

measures approximately one inch in diameter. The orbit is surrounded by layers of soft, fatty

tissue which protect the eye and enable it to turn easily. 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. Its main function is to receive and transmit images to

the brain. In humans there are three main types of light sensitive cells in the retina. They are [3],

• Rod Cells

•Cone Cells

• Ganglion Cells

There are about 125 million rods and cones within the retina that act as the eye’s photoreceptors.

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 1 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 [2].

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2.3 Vision Impairment

Damage or degeneration of the optic nerve, the brain, or any part of the visual pathway between

them, can impair vision.

2.4 Causes of Blindness

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.

2. Age-related macular degeneration

Retinitis Pigmentosa (RP) is the name given to a group of hereditary diseases of the retina of the

eye. In macular degeneration, a layer beneath the retina, called the Retinal Pigment Epithelium

(RPE), gradually wears out from its lifelong duties of disposing of retinal waste products [4].

Both of these diseases attack the retina, rendering the rods and cones inoperative, causing either

loss of peripheral vision or total blindness. However, it’s been found that neither of these retinal

diseases affects the ganglion cells or the optic nerve. This means that if scientists can develop

artificial cones and rods, information could still be sent to the brain for interpretation.

2.5. Corneal Transplants

Surgical removal of opaque or deteriorating corneas and replacement with donor transplants is a

common medical practice. Corneal tissue is a vascular; that is, the cornea is free of blood vessels.

Therefore corneal tissue is seldom rejected by the body’s immune system. Antibodies carried in

the blood have no way to reach the transplanted tissue, and therefore long-term success

following implant surgery is excellent [5].

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2.6 How eyes work?

The light coming from an object enters the eye through cornea and pupil. The eye lens converges

These light rays to form a real, inverted and diminished image on the retina. The light sensitive

Cells of the retina get activated with the incidence of light and generate electric signals. These

Electric signals are sent to the brain by the optic nerves and the brain interprets the electrical

Signals in such A way that we see an image which is erect and of the same size as the object.

Fig.2.4:How Eye Work

At the conclusion of the surgery, the surgeon will place a conformer (a plastic disc) into the

socket. The conformer prevents shrinking of the socket and retains adequate pockets for the

prosthesis. Conformers are made out of silicone or hard plastic. After the surgery, it takes the

patient from four to six weeks to heal. The artificial eye is then made and fitted by a professional

ocularist.

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2.7. The Surgery

This concept of Artificial Vision is also interesting to engineers, because there are a number of

technicalities involved in this surgery apart from the anatomical part. The microsurgery starts

with three incisions smaller than the diameter of a needle in the white part of the eye. Through

the incisions, surgeons introduce a vacuuming device that removes the gel in the middle of the

eye and replaces it with saline solution. Surgeons then make a pinpoint opening in the retina to

inject fluid in order to lift a portion of the retina from the back of the eye, creating a pocket to

accommodate the chip. The retina is resealed over the chip, and doctors inject air into the middle

of the eye to force the retina back over the device and close the incisions. During the entire

surgery, a biomedical engineer takes part actively to ensure that there is no problem with the chip

to be implanted. Artificial retinas constructed at SVEC consist of 100,000 tiny ceramic detectors,

each 1/20 the size of a human hair. The assemblage is so small that surgeons can’t safely handle

it. So, the arrays are attached to a polymer film one millimeter by one millimeter in size. A

couple of weeks after insertion into an eyeball, the polymer film will simply dissolve leaving

only the array behind [6].

The main part in our visual system is the eye. Our ability to see is the result of a process very

Similar to that of a camera. A camera needs a lens and a film to produce an image. In the same

Way, the eyeball needs a lens (cornea, crystalline lens, vitreous) to refract, or focus the light and

A film (retina) on which to focus the rays. The retina represents the film in our camera. It

Captures the image and sends it to the brain to be developed.

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Fig.2.5: Implanted Chip

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3. “SYSTEM FEATURES”

3.1. Artificial Silicon Retina

The brothers Alan Chow and Vincent Chow have developed a microchip containing 3500 photo

diodes, which detect light and convert it into electrical impulses, which stimulate healthy retinal

ganglion cells. The ASR requires no externally-worn devices. 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 “micro photodiodes,” 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 [7].

Fig.3.1: Magnified Image of ASR

Fig.3.2: ASR Implant in Eye

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

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“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. The original Opt bionics Corp. stopped operations, but Dr. Chow acquired the Opt bionics

name, the ASR implants and will be reorganizing a new company under the same name. The

ASR microchip is a 2mm in diameter silicon chip (same concept as computer chips) containing

~5,000 microscopic solar cells called “Micro photodiodes” that each have their own stimulating

electrode [8].

Fig.3.3: The Dot above the Date on this Penny is the Full Size of the ASR

As you can see in the picture at the top of this page, the ASR is an extremely tiny device, smaller

than the surface of a pencil eraser. It has a diameter of just 2 mm (.078 inch) and is thinner than a

human hair. There is good reason for its microscopic size. In order for an artificial retina to work

it has to be small enough so that doctors can transplant it in the eye without damaging the other

structures within the eye [2].

3.2. MARC System

The intermediary device is the MARC system. The schematic of the components of the MARC

to be implanted consists of a secondary receiving coil mounted in close proximity to the cornea,

a power and signal transceiver and 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. The biocompatibility of polyimide is being studied, and its

thin, lightweight consistency suggests its possible use as a non-intrusive material for an electrode

array. Titanium tacks or cyanoacrylate glue may be used to hold the electrode array in place [9].

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Fig.3.4: The MARC System

. The MARC system will operate in the following manner. An external camera will acquire an

image, whereupon it will be encoded into data stream which will be transmitted via RF

telemetry to an intraocular transceiver. A data signal will be transmitted by modulating the

amplitude of a higher frequency carrier signal. The signal will be rectified and filtered, and the

MARC will be capable of extracting power, data, and a clock signal. The subsequently derived

image will then be stimulated upon the patient’s retina [10].

Fig.3.5: Circuit of MARC System

The MARC system would consist of two parts which separately reside exterior and interior to the

eyeball. Each part is equipped with both a transmitter and a receiver. The primary coil can be

driven with a 0.5-10 MHz carrier signal, accompanied by a 10 kHz amplitude modulated

(AM/ASK) signal which provides data for setting the configuration of the stimulating electrodes.

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A DC power supply is obtained by the rectification of the incoming RF signal. The receiver on

the secondary side extracts four bits of data for each pixel from the incoming RF signal and

provides filtering, demodulation, and amplification. The extracted data is interpreted by the

electrode signal driver which finally generates appropriate currents for the stimulating electrodes

in terms of magnitude, pulse width, and frequency [11].

3.3. Engineering Details

First, for visually impaired people to derive the greatest benefit from an enhanced-vision system,

the image must be adapted to their particular blind areas and areas of poor acuity or contrast

sensitivity. Then the information arriving instantaneously at the eye must be shifted around those

areas. The thrust of all prosthetic vision devices is to use an electrode array to give the user

perceptions of points of light (phosphenes) that are correlated with the outside world. Thus, to

achieve the expected shift of the image across the stimulating electrode array, the camera

capturing the image must follow the wearer’s eye or pupil movements by monitoring the front of

the eye under Infrared (IR) illumination. The eye-position monitor controls the image camera’s

orientation. If the main image-acquisition camera is not mounted on the head, compensation for

head movement will be needed, as well. Finally, if a retinal prosthesis is to receive power and

signal input from outside the eye via an IR beam entering the pupil, the transmitter

Must be aligned with the intraocular chip. The beam has two roles: it sends power, and it is pulse

or amplitude-modulated to transmit image data. Under the control of eye movement, the main

imaging camera for each eye can swivel in any direction. Each of these cameras--located just

outside the users’ field of view to avoid blocking whatever peripheral vision they might have-

captures the image of the outside world and transmits the information through an optical fiber to

a signal-processing computer worn on the body. The chip which is inserted on the retina is coded

using the computer programmatic languages. After the implantation, the working of the bionic

eye is compared with the normal view through necessary algorithms so that measures are taken

that can rectify the abnormalities.

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3.4 Visual System

The human visual system is remarkable instrument. It features two mobile acquisition units each

has formidable preprocessing circuitry placed at a remote location from the central processing

system (brain). Its primary task include transmitting images with a viewing angle of at least

140deg and resolution of 1 arc min over a limited capacity carrier, the million or so fibers in

each optic nerve through these fibers the signals are passed to the so called higher visual cortex

of the brain. The nerve system can achieve this type of high volume data transfer by confining

such capability to just part of the retina surface, whereas the center of the retina has a 1:1 ration

between the photoreceptors and the transmitting elements, the far periphery has a ratio of 300:1.

This results in gradual shift in resolution and other system parameters. At the brain’s highest

level the visual cortex an impressive array of feature extraction mechanisms can rapidly adjust

the eye’s position to sudden movements in the peripherals filed of objects too small to se when

stationary. The visual system can resolve spatial depth differences by combining signals from

both eyes with a precision less than one tenth the size of a single photoreceptor.

Fig.3.6: Visual System

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4. “WORKING PROCEDURE”

An artificial eye provokes visual sensations in the brain by directly stimulating different parts of

the optic nerve.

Fig. 4.1: Working of Bionic Eye

A bionic eye works by stimulating nerves, which are activated by electrical impulses. In this case

the patient has a small device implanted into the body that can receive radio signals and transmit

those signals to nerves. The Argus II implant consists of an array of electrodes that are attached

to the retina and used in conjunction with an external camera and video processing system to

provide a rudimentary form of sight to implanted subjects The Argus II Retinal Prosthesis

System can provide sight, the detection of light, to people who have gone blind from

degenerative eye diseases. Diseases damage the eyes’ photoreceptors, the cells at the back of the

retina that perceive light patterns and pass them on to the brain in the form of nerve impulses,

where the impulse patterns are then interpreted as images. The Argus II system takes the place of

these photoreceptors. The second incarnation of Second Sight’s retinal prosthesis consists of five

main parts:

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Digital Camera - built into a pair of glasses, captures images in real-time sends images to

microchip.

Video processing microchip - built into a handheld unit, processes images into electrical

pulses representing patterns of light and dark; sends pulses to radio transmitter in glasses

Radio transmitter - wirelessly transmits pulses to receiver implanted above the ear or

under the eye

Radio receiver - receiver sends pulses to the retinal implant by a hair-thin, implanted

wire

Retinal implant - array of 60 electrodes on a chip measuring 1 mm by 1 mm [12]

The entire system runs on a battery pack that is housed with the video processing unit. When the

camera captures an image-of, say, a tree-the image is in the form of light and dark pixels. It

sends this image to the video processor, which converts the tree-shaped pattern of pixels into a

series of electrical pulses that represent “light” and “dark.” The processor sends these pulses to a

radio transmitter on the glasses, which then transmits the pulses in radio form to a receiver

implanted underneath the subject’s skin. The receiver is directly connected via a wire to the

electrode array implanted at the back of the eye, and it sends the pulses down the wire. When the

pulses reach the retinal implant, they excite the electrode array. The array acts as the artificial

equivalent of the retina’s photoreceptors. The electrodes are stimulated in accordance with the

encoded pattern of light and dark that represents the tree, as the retina’s photoreceptors would be

if they were working (except that the pattern wouldn’t be digitally encoded). The electrical

signals generated by the stimulated electrodes then travel as neural signals to the visual center of

the brain by way of the normal pathways used by healthy eyes -- the optic nerves. In macular

degeneration and retinitis pimentos, the optical neural pathways aren’t damaged. The brain, in

turn, interprets these signals as a tree, and tells the subject, “You’re seeing a tree” [12].

All of this takes some training for subjects to actually see a tree. At first, they see mostly light

and dark spots. But after a while, they learn to interpret what the brain is showing them, and

eventually perceive that pattern of light and dark as a tree. Thus bionic eye helps a blind people

to see the objects and recognize them.

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Fig.4.2: After Surgery

4.1. Structure of the Micro Detectors

The ceramic micro detectors resemble the ultra-thin films found in modern computer chips. The

arrays are stacked in a hexagonal structure, which mimics the arrangement of the rods and cones

it has been designed to replace.

4.2. The Prototype Implant

The first implant had just 16 electrodes on the retinal pad and, as a result, visual information was

limited. The new device has 60 electrodes and the receiver is shrunk to one-quarter of the

original’s size. It is now small enough to be inserted into the eye socket itself. The operation to

fit the implant will also last just 1.5 hours, down from 7.5 hours.

4.3. Implantation

An incision is made in the white portion of the eye and the retina is elevated by injecting fluid

underneath, comparing the space to a blister forming on the skin after a burn. Within that little

blister, we place the artificial retina [2].

A light-sensitive layer covers 65% of the interior surface of the eye. Scientists hope to replace

damaged rods and cones in the retina with ceramic micro detector arrays [2].

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Fig.4.3: What the Person Can See?

4.4. Some Facts about Bionic Eyes

Scientists at the Space Vacuum Epitaxy Centre (SVEC) based at the University of Houston,

Texas, are using a new material, comprising tiny ceramic photocells that could detect incoming

light and repair malfunctioning human eyes. Scientists at SVEC are conducting preliminary tests

on the biocompatibility of this ceramic detector. The artificial retinas constructed at SVEC

consist of 100,000 tiny ceramic detectors, each 1/20th the size of a human hair. The assemblage

is so small that surgeons can’t safely handle it. So, the arrays are attached to a polymer film one

millimeter in size. After insertion into an eyeball, the polymer film will simply dissolve leaving

only the array behind after a couple of weeks [16].

Prototyping Devices

Researchers at Bionic Vision Australia (BVA) have produced a prototype version of a bionic eye

implant that could be ready to start restoring rudimentary vision to blind people as soon as 2013.

The system consists of a pair of glasses with a camera built in, a processor that fits in your

pocket, and an ocular implant that sits against the retina at the back of the eye and electronically

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stimulates the retinal neurons that send visual information to the brain. The resulting visual

picture is blocky and low-res at this point, but the technology is bound to improve, and even in

its current form it’s going to be a major life-changer for those with no vision at all. And the

future potential - even for sighted people - is fascinating. There are two prototypes being

developed to suit the needs of different patient groups [13].

A. Wide-View Device

The first prototype bionic eye, known as the wide-view device, will use around 100 electrodes to

stimulate the nerve cells in the back of the eye. This will allow people with severe vision loss to

see the contrast between light and dark shapes regain mobility and independence. This device

may be most suitable for retinitis pigmentosa patients [14].

B. High-Acuity Device

The second prototype, known as the high-acuity device, will use 1000 electrodes to stimulate the

retina and will provide patients with more detailed information about the visual field, helping

them recognize faces and even read large print. The high-acuity device may be most suitable for

patients with age-related macular degeneration; however, it is still some years before the first

patient tests will commence [14].

C. Diamond Device

Melbourne researchers working to restore sight to the vision impaired believe diamond is the

best material with which to build a bionic eye and hope to have a prototype in testing within the

next few years.

Kumar Gamesman, a physicist helping to design a bionic eye for Bionic Vision Australia at the

University of Melbourne, says metals such as platinum and iridium are currently used for

implants. He says even the hardest metals deteriorate within five to 10 years, which is why

researchers have turned their focus to diamonds. “We made a diamond device so the implant

inside the eye will not deteriorate or will not be damaged by any other means,” he said [15].

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Fig.4.4: How the Bionic Person Looks? Fig.4.5: Fig. 13: The Bionic Eye

4.5 The Manufacturing Process

The time to make an ocular prosthesis from start to finish varies with each ocularist and the

individual patient. A typical time is about 3.5 hours. Ocularists continue to look at ways to

reduce this time. There are two types of prostheses. The very thin, shell type is fitted over a

blind, disfigured eye or over an eye which has been just partially removed. The full modified

impression type is made for those who have had eyeballs completely removed. The process

described here is for the latter type.

1. The oculists inspects the condition of the socket. The horizontal and vertical dimensions and

the periphery of the socket are measured.

2. The ocularist paints the iris. An iris button (made from a plastic rod using a lathe) is

Selected to match the patient's own iris diameter. Typically, iris diameters range from 0.4-

0.52 In (10-13 mm). The iris is painted on the back, flat side of the button and checked

Against the patient's iris by simply reversing the buttons so that the color can be seen through the

dome of plastic. When the color is finished, the ocularist removes the

Conformer, which prevents contraction of the eye socket.

3. Next, the ocularist hand carves a wax molding shell. This shell has an aluminum iris

Button imbedded in it that duplicates the painted iris button. The wax shell is fitted into

The patient's socket so that it matches the irregular periphery of the socket. The shell may

Have to be reinserted several times until the aluminum iris button is aligned with the

Patient's remaining eye. Once properly fitted, two relief holes are made in the wax shell.

4. The impression is made using alginate, a white powder made from seaweed that is mixed

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With water to form a cream, which is also used by dentists to make impressions of gums.

After mixing, the cream is placed on the back side of the molding shell and the shell is

Inserted into the socket. The alginate gels in about two minutes and precisely duplicates

The individual eye socket. The wax shell is removed, with the alginate

Fig.4.6: Manufacturing Process

4.6 Orbital Implants

Should eye removal be necessary, the surgeon will likely place an orbital implant to recover?

Some of the volume lost in the evisceration or enucleation. The orbital implant is attached to the

4 rectus muscles, providing movement of the implant with the fellow eye. Typically, the better

The movement of the implant, the better the motility of the artificial eye or scleral shell. Implant

choices may be dictated by the conditions indicating eye removal, the surgeon's

Preference and your post-removal objectives. Most implants are spherical in shape, but other

Shapes are possible. Implants can also be coated or wrapped in donor sclera or alloderm

Materials. Below is a list of typical orbital implants: While implant type is an important decision

to one facing enucleation or evisceration, the most

Important factor is surgical technique. If you are facing the option of eye removal, we

Recommend that you contact your local ocularist for a recommendation of oculoplastic or

Ophthalmic surgeons in your area.

25

CONCLUSION

Bionic devices are being developed to do more than replace defective parts. Researchers are also

using them to fight illnesses. If this system is fully developed it will change the lives of millions

of people around the world. We may not restore the vision fully, but we can help them at least to

find their way, recognize faces, read books, distinguish between objects such as cups and plates,

above all lead an independent life. Though there are a number of challenges to be faced before

this technology reach the common man, the path has been laid. It has enabled a formerly blind

patient to. But with only 16 electrodes, the device does not allow the patient to see a clear

picture. For that, thousands of electrodes are neede on the same size of the chip.The bionic eye

has changed the world of the visually challenged people.We are sure that higher quality,better

resolution,even color are possible in the future.Restoration of sight for the blind is no more

dream today.Bionic eye have made this true.

26

REFERENCES

1. www.studymafia.org

2. NAGARJUNA SHARMA “BIONIC EYE”, SCRIBD, 2010.

3. American Academy of Ophthalmology, 655 Beach St. San Francisco, CA 94109, 415-

561-8500.

4. http://www.eyenet.org/aao_index.html (http://www.eyenet.org/aao_index.html).

5. Ocular Surgery News. http://www.slackinc.com/eye/osn/osnhome.htm

6. http://www.slackinc.com/eye/osn/osnhome.htm.

7. "Integrated Orbital Implants." http://www.ioi.com

8. http://www.questia.com/library/1G168842005/twoviewsofartificialeyes

9. Artificial Intelligence with 'Eyes' ; IBM Buying Company to Enhance Medical.

10. http://www.questia.com/library/1P238597390/Artificial intelligence eye

27

APPENDIX

Researchers are already planning a third version that has 1,000 electrodes on the retinal implant,

which they believe could allow for facial-recognition capabilities and hope to allow the user to

see colorful images. Scientists believe the immediate goal after achieving above is to develop a

functioning artificial retina with resolution that mimics human sensors. Once this step has been

achieved, they says, then attention can be brought to bear on color vision, followed by the

replacement of some of the interconnecting neural cells that lead to the optic nerve. So, let us

hope to reach all these goals as soon as possible. The researchers note the device has some

limitations, and it will not restore perfect vision. However, they are sure it will give people the

advantage of having a general sense of their surroundings. Hopefully, the technology may enable

people to recognize faces and facial expressions. “The thing is to significantly improve the

quality of life for blind patients"

A bionic eye works by stimulating nerves, which are activated by electrical impulses. In this case

the patient has a small device implanted into the body that can receive radio signals and transmit

those signals to brain through nerves and can interpret the image. One of the most dramatic

applications of bionics is the creation of artificial eyes. Early efforts used silicon-based photo

detectors, but silicon is toxic to the human body and reacts unfavorably with fluids in the eye..