Bionic Eye

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BIONIC EYE (Electronically powered eye) Presented by:
Salma Khanam.H.M - VI SEMESTER Asfia Samreen – VI SEMESTER Department of Instrumentation Technology, KBN College of Engineering, Gulbarga

ABSTRACT
Researches working for the Boston Retinal Implant Project have been developing a Bionic eye implant that could restore the eye sight of people who suffer from age related blindness. The implant is based on a small chip that is surgically implanted behind the retina, at the back of the eye ball. An ultra-thin wire strengthens the damaged optic nerve; its purpose is to transmit light and images to the brain’s vision system, where it is normally processed. Other than the implanted chip and wire, most of the device sits outside the eye. The users would need to wear special eye glasses battery-powered camera and a transmitter, which would send images to the chip implanted behind the retina. The new device is expected to be quite durable, since the chip is enclosed in a Titanium casing, making it both water-proof and corrosion-proof. The researches estimate that the device will last for at least 10years inside the eye.

go inside your eye and couple your eye movement to where the camera is,” said Dr Humayun.

2. THE 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 whole process, as complex as it is, would not be possible if it were not for the presence of light. Without light, there would be no sight. The human eye is the organ which gives us the sense of sight, allowing us to learn more about the surrounding world than any of the other five senses.

1. INTRODUCTION
The purpose of the report is to provide an accurate and detailed description of the Bionic eye(Optoelectronic Retinal Prosthesis System) and its function. The new technology tested by Mrs.Moorfoot uses an external camera worn on a pair of dark glasses that sends images to a radio receiver implanted near the eye that transmits the signal on to a tiny silicon and platinum chip that sits on the retina. This information then goes down the optic nerve into the brain. The team lead by Dr. Mark Humayun, professor of ophthalmology and Biomedical engineering at the Doheny eye institute in Los Angeles, California have now developed a small and powerful camera that could be implanted inside the patient’s eye, rather than worn on a pair of glasses. “The camera is very, very small and very low power, so it can

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

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important part of an eye that is responsible for vision is retina. The retina lies at the back of the eye and it acts like the film in a camera, receiving and processing everything you see. In humans there are two types of light sensitive cells in the retina: • Rod Cells • Cone Cells

Age related Macular Degeneration (AMD) usually affects people over the age of 50 and there are two distinct types - "wet" AMD and "dry" AMD. "Wet" AMD results from the growth of new blood vessels in the choroid, causing an accumulation of fluid in the macula which leads to retinal damage. This type of degeneration can often be successfully arrested by laser surgery. "Dry" AMD represents at least 80% of all AMD cases and results in atrophy of the Retina. Usually yellowish-white round spots called drusen first appear in a scattered pattern deep in the macula. Later degeneration of both the Pigment Epithelium and the cones begins. While AMD is not inherited in a predictable way, heredity may be involved to some extent.

2.1 What are Rod cells and Cone cells?
Rod cells pick up movement out of the corner of the eye and also, in a normal eye it is the rods that operate in poor light or at night. There are about 120 million rods in each eye and they are more numerous towards the outer edge of the retina The cone cells are used in colour vision and in close precision work like reading. There are not as many cones and they are more concentrated in the centre of the retina (the Macula).

3. BIONIC EYE

2.2 Disease of eye
• • Retinitis pigmentosa Macular degeneration

2.2.1 Retinitis pigmentosa Retinitis Pigmentosa (RP) is the name given to a group of hereditary diseases of the retina of the eye. RP may be caused by a breakdown in the function of the rods or the cones in some part of the retina. The retina is so complex that breakdowns may occur in a variety of ways and so RP is not a single disorder but a great number of disorders. The breakdown of cone function may be called Macular Degeneration. 2.2.2 Macular Degeneration Macular is a sensitive area in the centre of the retina which provides us with sight in the centre of our field of vision. It allows us to see the fine details when we look directly at something. 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. A large proportion of macular degeneration cases are age- related.

A group of American scientists have given a visually impaired grandmother a chance to see her grandchildren dance and play football with a “Bionic eye”. Linda Moorfoot, who suffers from the eye condition Retinitis Pigmentosa that causes blindness,is thrilled after having part of her sight restored by a Bionic eye.

3.1 Artificial Silicon Retina (ASR)
The ASR is a silicon chip 2 mm in diameter and 1/1000 inch in thickness. It contains approximately 3,500 microscopic solar cells called "microphotodiodes," each having its own stimulating electrode. These microphotodiodes are designed to convert the light energy from images into thousands of tiny electrical impulses to

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stimulate the remaining functional cells of the retina in patients suffering with AMD and RP types of conditions.

ASR implant in eye 3.2 How Artificial Vision Will Work? Creating artificial sight: The current path that scientists are taking to create artificial vision received a jolt in 1988, when Dr. Mark Humayun demonstrated that a blind person could be made to see light by stimulating the nerve ganglia behind the retina with an electrical current. This test proved that the nerves behind the retina still functioned even when the retina had degenerated. Based on this information, scientists set out to create a device that could translate images and electrical pulses that could restore vision.

Magnified image of ASR The ASR is powered solely by incident light and does not require the use of external wires or batteries. When surgically implanted under the retina, in a location known as the sub retinal space, the ASR is designed to produce visual signals similar to those produced by the photoreceptor layer. From their sub retinal location these artificial "photoelectric" signals from the ASR are in a position to induce biological visual signals in the remaining functional retinal cells which may be processed and sent via the optic nerve to the brain. The dot above the date on this penny is the full size of the ASR Today, such a device is very close to becoming available to the millions of people who have lost their vision to retinal disease. 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.

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3.3 Bionic eye implants
A bionic eye implant that could help restore the sight of millions of blind people could be available to patients within two years.

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 [3,14], thin silicon[9], or polyimide[25] with ribbon cables connecting the devices. The biocompatibility of polyimide [10,11] is being studied, and its thin, lightweight consistency suggests its possible use as a non-intrusive material for an electrode array. Titanium tacks[12] or cyanoacrylate glue[13] may be used to hold the electrode array in place.

3.4 New Bionic Eye Could Restore Sight
Researchers working for the Boston Retinal Implant Project have been developing a bionic eye implant that could restore the eye sight of people who suffer from age-related blindness. The implant is based on a small chip that is surgically implanted behind the retina, at the back of the eyeball. An ultra-thin wire strengthens the damaged optic nerve; its purpose is to transmit light and images to the brain's vision system, where it is normally processed. Other than the implanted chip and wire, most of the device sits outside the eye. The users would need to wear special eye glasses containing a tiny batterypowered camera and a transmitter, which would send images to the chip implanted behind the retina. The new device is expected to be quite durable, since the chip is enclosed in a titanium casing, making it both water-proof and corrosion- proof. The researchers estimate that the device will last for at least 10 years inside the eye.

Figure 2A: The MARC System

3.6 Overall System Functionality
The MARC system, pictured in Figures 1-4 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. As shown in Figures 1-5, 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

3.5 The MARC System
In our case, the intermediary device is the MARC system pictured in Figures 2A and 2B. The schematic of the components of the MARC to be implanted consists of a secondary receiving coil

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who has co-directed the project with MIT's John Wyatt since 1988.

3.8 Disadvantages
The scientists explain that the bionic eye will be affective for individuals who once had sight, since their brain knows how to process visual information. The unfortunate people who were born blind do not have the neurological capability to process the data received via the wire. Furthermore, the optic nerve must be at least partly functional. Otherwise, the data will not be fully processed. For many individuals that were born blind, this is a problem as well, since their optic nerve has never been used. This new technology will not be helpfull for glaucoma patients.

receiver. The primary coil can be driven with a 0.510 MHz carrier signal, accompanied by a 10 kHz amplitude modulated (AM/ASK) signal which provides data for setting the configuration of the stimulating electrodes. 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.

4. CONCLUSION
Its been 40 years since Arne Larsson received the first fully implanted cardiac pacemaker at the Karolinska Institute in Stockholm.Researchers throughout the world have looked for ways to improve people's lives with artificial, bionic devices.Bionic devices are being developed to do more than replace defective parts. Researchers are also using them to fight illnesses.Providing power to run bionic implants and making connections to the brain's control system pose the two great challenges for biomedical engineering.We are now looking at devices like bionic arms, tongues, noses etc. YES, this is Bionic eye:

3.7 Advantages
Although the device will not be able to restore the eye sight of the entire blind community, researchers are certain many people will benefit from the technology. For instance, age-related macular generation is the leading cause of blindness in the industrialized world, with about 2 million Americans currently suffering from the condition. The new technology will hopefully assist people suffering from this condition, and individuals suffering from retinitis pigmentosa (a genetic condition), but will not help glaucoma patients. 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," said Joseph Rizzo of the Massachusetts Eye and Ear Infirmary,

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REFERENCES 
Image processing for a high-resolution optoelectronic retinal prosthesis. Asher, A; Segal, WA; Baccus, SA; Yaroslavsky, LP; Palanker, DV; IEEE Transactions on Biomedical Engineering, 54(6): 993-1004 (2007). Optoelectronic retinal prosthesis: system design and performance. J.D. Loudin, D.M. Simanovskii, K. Vijayraghavan, C.K. Sramek, A.F. Butterwick, P. Huie, G.Y. McLean, and D.V. Palanker. Journal of Neural Engineering, 4: S72–S84 (2007). High-Resolution Electronic Retinal Prosthesis: Physical Limitations and Design. D. Palanker, A. Vankov, P. Huie, A. Butterwick, I. Chan, M.F. Marmor and M.S. Blumenkranz; Chapter 14 in ARTIFICIAL SIGHT: BASIC RESEARCH,BIOMEDICAL ENGINEERING, AND CLINICAL ADVANCES; M.S. Humayun, J.D. Weiland, G. Chader, E. Greenbaum (Eds.), Springer Series: Biological and Medical Physics, Biomedical Engineering, New York, 2007. Effect of shape and coating of a subretinal prosthesis on its integration with the retina. A. Butterwick, P. Huie, B.W. Jones, R.E. Marc, M. Marmor, D. Palanker. Experimental Eye Research www.physorg.com/news3592.html www.timesonline.co.uk/tol/news/uk/health/a rticle3790683.ece www.switched.com/2008/04/22/electroniceye-implant-may-give-sight-to-blind gizmodo.com/366191/researchers-createbionic-eye-prototype-render-guide-dogsobsolete







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