COLLEGE FEST/BOOKS/ANY ADS

1000 VIEW PER DAY

2$ OR 100RS/ MONTH

PPT ON ELECTRONIC EYE


ABSTRACT: Electronic eye will be a wonderful boon that will restore eyesight for millions of people .25 million people are blind because one layer of cells on their retinas no longer works .By 2020 the figure is expected to be double .Now we are at the beginning of the end of blindness with this type of technology. Using advanced communication technology researchers are developing an artificial retina. They are investigating several electronic-based strategies designed to bypass various defects or missing links along the brain's image processing pathway and provide some form
of artificial sight. For example, with the help of an experimental artificial retina, a man who has been blind for 50 years is now able to see. This paper is about curing blindness. Due to the advanced communication technology, the scientists have made the commitment to the development of technology that will provide or restore vision for the visually impaired around the world. This paper describes the development of Electronic Eye system, which cures blindness to some extent. This paper explains the process involved in it and explains the concepts of artificial silicon retina, cortical implants etc. Finally the advancements made in this system and scope of this in the future is also presented clearly. INTRODUCTION: The eye is one of the most amazing organs in the body. Before we understand how an electronic eye is created its important to know about the important role that the retina plays in how we see. Here is a simple explanation of what happens when we look at an object: • Scattered light from the object enters through the cornea. • The light is projected onto the retina. • The retina sends messages to the brain through the optic nerve. • The brain interprets what the object is. Figures (1.2): the internal view of the eye and its path view The retina is complex in itself. This thin membrane at the back of the eye is a vital part of our ability to see. Its main function is to receive and transmit images to the brain. These are the three main types of cells in the eye that help perform this function: Rods, Cones and Ganglion Cells. The information received by the rods and cones are 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. There are a number of retinal diseases that attack these cells, which can lead to blindness. The most notable of these diseases are retinitis pimentos and age-related macular degeneration. 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. This concept laid the foundation for the invention of the ELECTRONIC EYE SYSTEM technology. HOW TO CREATE ELECTRONIC EYE? The current path that scientists are taking to create electronic eye 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. Today, such a device is very close to be available to the millions of people who have lost their vision to retinal disease. In fact, there are at least two silicon microchip devices that are being developed. The concept for both devices is similar, with each being: • Small enough to be implanted in the eye • Supplied with a continuous source of power • Biocompatible with the surrounding eye tissue Figures (3.4) the dot above the date on this penny is the full size of the Artificial Silicon Retina Perhaps the more promising of these two silicon devices is the ARTIFICIAL SILICON RETINA (ASR). The ASR is an extremely tiny device. It has a diameter of just 2 mm (.078 inch) and is thinner than a human hair. It contains approximately 5000 microscopic solar cells called “MICRO PHOTODIODES”, each with its own stimulating electrode 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. Groups of researchers have found that blind people can see spots of light when electrical currents stimulate cells, following the experimental insertion of an electrode device near or into their retina. Some patients even saw crude shapes in the form of these light spots. This indicates that despite damage to cells in the retina, electronic techniques can transmit signals to the next step in the pathway and provide some form of visual sensation. Researchers are currently developing more sophisticated computer chips with the hope that they will be able to transmit more meaningful images to the brain. How ARTIFICIAL SILICON RETINA works? The ASR contains about 5000 microscopic solar cells that are able to convert light into electrical pulses, mimicking the function of cones and rods. To implant this device into the eye, surgeons make three tiny incisions no larger than the diameter of a needle in the white part of the eye. Through these incisions, the surgeons introduce a miniature cutting and vacuuming device that removes the gel in the middle of the eye and replaces it with saline. Next, a pinpoint opening is made in the retina through which they inject fluid to lift up a portion of the retina from the back of the eye, which creates a small pocket in the sub retinal space for the device to fit in. The retina is then resealed over the ASR. Figure 5: Here you can see where the ASR is placed between the outer and inner retinal layers For any micro chip to work it needs power and the amazing thing about the ASR is that it receives all of its needed power from the light entering the eye. This means that with the ASR implant in place behind the retina, it receives all of the light entering the eye. This solar energy eliminates the need for any wires, batteries or other secondary devices to supply power. Another microchip device that would restore partial vision is currently in development called the artificial retina component chip (ARCC); this device is quite similar to the ASR. Both are made of silicon and both are powered by solar energy. The ARCC is also a very small device measuring 2 mm square and a thickness of .02 millimeters (.00078 inch). There are significant differences between the devices, however. According to researchers, the ARCC will give blind patients the ability to see 10 by 10 pixel images, which is about the size of a single letter on this page. However, researchers have said that they could eventually develop a version of the chip that would allow 250 by 250 pixel arrays, which would allow those who were once blind to read a newspaper. WORKING OF ELECTRONIC EYE SYSTEM: The main parts of this system are miniature video camera, a signal processor, and the brain implants. The tiny pinhole camera, mounted on a pair of eyeglasses, captures the scene in front of the wearer and sends it to a small computer on the patient's belt. The processor translates the image into a series of signals that the brain can understand, and then sends the information to the brain implant that is placed in patient’s visual cortex. And, if everything goes according to plan, the brain will "see" the image. Figures (6.7) illustrating the E- EYE SYSTEM. Light enters the camera, which then sends the image to a wireless wallet-sized computer for processing. The computer transmits this information to an infrared LED screen on the goggles. The goggles reflect an infrared image into the eye and on to the retinal chip, stimulating photodiodes on the chip. The photodiodes mimic the retinal cells by converting light into electrical signals, which are then transmitted by cells in the inner retina via nerve pulses to the brain. The goggles are transparent so if the user still has some vision, they can match that with the new information - the device would cover about 10° of the wearer’s field of vision. The patient should wear sunglasses with a tiny pinhole camera mounted on one lens and an ultrasonic range finder on the other. Both devices communicate with a small computer carried on his hip, which highlights the edges between light and dark areas in the camera image. It then tells an adjacent computer to send appropriate signals to an array of small electrodes on the surface of patient’s brain, Through wires entering his skull. The electrodes stimulate certain brain cells, making the person perceive the specks of light. The shifting patterns as scans across a scene tells him where light areas meet dark ones, letting him find the black cap on the white wall, for example. The device provides a sort of tunnel vision, reading an area about the size of a card 2 inches wide and 8 inches tall, held at arm's length. People with electronic eye: IMAGE PROCESSING IN BIONIC EYE: Once the image is entered the glass it is processed into 5kg computer it process the image and send signals to Asr in back of eye and from there it go to brain implant through optic nerves and brain is able to interrupt what the image is let us see how image looks in electronic eye What type of blind patients would not be able to use this device? We believe the device will be applicable to virtually all patients who are blind or who have very low vision. The only ones contraindicated would be a few blinded by serious brain damage, or who have chronic infections, etc. that preclude surgical implants. Patients who have a small amount of vision are not contraindicated. Visual cortex stimulation seems to work the same in both sighted and blind patients. ORGANISATIONS WORKING ON ARTIFICIAL RETINA: The blindness foundation groups research center at JOHNS HOPKINS UNIVERSITY, HARVARD MEDICAL SCHOOL, MASSACHUSETTS INSTITUTE OF TECHNOLOGY AND UNOVERSITY OF UTAH. DRAWBACKS OF ELECTRONIC EYE: 1. The first and foremost thing is the cost .The miniaturization of equipment and more powerful computers have made this electronic eye possible, but it's not cheap: The operation, equipment and necessary training cost $70,000 per patient. And also may be much higher depending upon the context and severity. 2. It may not work for people blinded as children or as infants, because the visual cortex does not develop normally. But it will work for the vast majority of the blind -- 98 to 99 percent. 3. Researchers caution, however, that artificial vision devices are still highly experimental and practical systems are many years away. Even after they are refined, the first wave will most likely provide only crude images, such as the outline of a kitchen doorway. It does not function as well as the real eye, and does not have crystal-clear vision (as it is only a camera).The device is a very limited navigational aid, and it's a far cry from the visual experience normal people enjoy. CONCLUSION: The electronic eye is the latest system aimed at helping millions of blind and visually impaired people. The first useful electronic eye is now helping a blind man walk safely around and read. Several efforts are now underway to create vision in other ways for blind people. While technically exciting, much more work in this area needs to be completed before anything is available to the majority of patients. Research is ongoing in two areas: cortical implants and retinal implants. There is still an enormous amount of work to be done in developing artificial retinas. In the long run, there could be the possibility of brain implants. A brain implant or cortical implant provides visual input from a camera directly to the brain via electrodes in contact with the visual cortex at the backside of the head. BIBILIOGRAPHY: BOOKS: 1. “ELECTRONICS FOR YOU” (SEPTEMBER 2006). 2. “Artificial Vision for the Blind by Connecting a Television Camera to the Brain" ASAIO Journal WEB: www.artificialvision.com www.optobionics.com

CSE PAPER PRESENTATIONS

0 comments:

Post a Comment

Note: only a member of this blog may post a comment.

 

© 2011 Study Unique - Designed by Mukund | ToS | Privacy Policy | Sitemap

About Us | Contact Us | Write For Us