EC0271 BIONIC EYE (“Offers New Hope of Restored Vision”)
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EC0271 BIONIC EYE (“Offers new hope of restored vision”) [1]SOWMYA.U.L [2] KALYANI.D.P ICE-2/4 ICE-2/4 GNITS-Hyderabad GNITS-Hyderabad BIONIC EYE (“Offers light at the end of tunnel for blind”) Introduction: Blindness is more feared by the people than any ailment except cancer and AIDS. The bionic eye is a bionic replacement part in the human body. Bionic eyes allow for advanced vision and repairs sight like a camera. Scientists are developing a bionic eye that may help to restore sight to people affected by two of the most common forms of blindness. They are: 1. Retinitis Pigmentosa 2. Age-Related Macular Degeneration. In these diseases the photoreceptor cells slowly degenerate, leading to blindness. However, many of the retinal neurons that transmit signals from the photoreceptors are preserved for a prolonged period of time. The tiny implant employs technology similar to that of a digital camera. The device would contain an imaging detector with hundreds of pixels coupled to microscopic stimulating electrodes. If light forms an image on the detector, then the result will be electrical stimulation of the retina in the shape of this image. A bionic eye that can restore sight to the blind should be available commercially. The artificial retina has been cleared by US regulators to begin trials on between 50 and 75 people suffering from two of the most common causes of blindness, opening the way for millions more to benefit from similar implants in the future. If the research progresses well, a device could be on the market early in 2009. An early version of the prosthetic retina has already been fitted to six patients with retinitis pigmentosa, a degenerative and incurable eye condition that affects 1 in 3,500 people. All have recovered the ability to detect light and motion, and even to make out large letters and to distinguish between objects such as a cup, a knife and a plate. The second-generation device that is now starting trials should provide even better vision, as it contains 60 light-sensitive electrodes, compared with 16 in the previous model. More improvements are expected within five to seven years with a 1000-electrode implant that will enable previously blind people to recognize faces. “The ultimate aim is to allow people recognize faces, and to allow the completely blind to get around on their own.” Specifications: This diagram shows the functioning of a bionic when arranged in a human eye. BIONIC EYE TECHNOLOGY 1: Camera on glasses views image 2: Signals are sent to hand-held device 3: Processed information is sent back to glasses and wirelessly transmitted to receiver under surface of eye 4: Receiver sends information to electrodes in retinal implant 5: Electrodes stimulate retina to send information to brain History: Scientific research since at least the 1950s has investigated interfacing electronics at the level of the retina, optic nerve, thalamus, and cortex. Visual prosthetics, which have been implanted in patients around the world both acutely and chronically, have demonstrated proof of principle, but do not yet offer the visual acuity of a normally sighted eye. Biological considerations: The ability to give sight to a blind person via a bionic eye depends on the circumstances surrounding the loss of sight. For retinal prostheses, which are the most prevalent visual prosthetic under development (due to ease of access to the retina among other considerations), vision loss due to degeneration of photoreceptors (retinitis pimentosa, choroideremia, geographic atrophy macular degeneration) is the best candidate for treatment. Candidates for visual prosthetic implants find the procedure most successful if the optic nerve was developed prior to the onset of blindness. Persons born with blindness may lack a fully developed optical nerve, which typically develops prior to birth. Technological considerations: Visual prosthetics are being developed as a potentially valuable aide for individuals with visual degradation. The visual prosthetic in humans remains investigational. Field of View: 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. Currently recipients of the device experience a relatively narrow view, but more electrodes should provide a greater field of vision. By stimulating more ganglion cells, one can hope that visual acuity will increase dramatically. Hence, scientist’s next goal is to design a device with 1000 electrodes. Regaining sight has felt like a miracle to those involved in the preliminary trial. At the beginning, it was like seeing assembled dots - "now it's much more than that." People, whose blindness results from a range of causes, including retinitis pigmentosa and macular degeneration could benefit from it. Although not truly an active prosthesis, an Implantable Miniature Telescope is one type of visual implant that has met with some success in the treatment of end-stage age-related macular degeneration. This type of device is implanted in the eye's posterior chamber and works by increasing (by about three times) the size of the image projected onto the retina in order to overcome a centrally-located scotoma or blind spot. Brain change: The new implant has a higher resolution than the earlier devices, with 60 electrodes. It is also a lot smaller, about one square millimeter, which reduces the amount of surgery that needs to be done to implant the device. The technology has now been given the go-ahead by the US Food and Drug Administration to be used in an exploratory patient trial. Using space technology, scientists have developed extraordinary ceramic photocells that could repair malfunctioning human eyes. Capabilities: The idea of a bionic eye might sound like something out of science fiction. Instead it is serious research that is going on. Bionic eye encompasses both night vision (zero moon illumination) and infrared (IR) capabilities with auto focus 20/15 clarity at all distances. Automatic adjustment to all light levels. Flash resistant. Biological eye will be banked and replaced at the end of member’s service. Fifteen year internal power source based on normal combat age range. Selected units with night missions, voluntary receiver and mandatory removal. Enables IR identification of friendly forces. Limited battery life ensures return for replacement of original eye. This would be capable of producing an image similar to that of the LED display of a digital camera. This photo is a simulated comparison of normal vision (left), Vision impaired by acute macular degeneration affecting the area of the retina responsible for detailed central vision (center) and The vision of a person using the Implantable Miniature Telescope (right). Functioning: Rods and Cones. Millions of them are in the back of every healthy human eye. They are biological solar cells in the retina that convert light to electrical impulses -- impulses that travel along the optic nerve to the brain where images are formed. Without them, we're blind. Indeed, many people are blind -- or going blind -- because of malfunctioning rods and cones. Retinitis pigmentosa tends to be hereditary and may strike at an early age, while macular degeneration mostly affects the elderly. The tiny implant employs technology similar to that of a digital camera. It works by mimicking the action of the retina, the lining at the back of the eye that converts light into signals to the brain. The implant translates light into electrical impulses and stimulates the retina, fooling the brain into thinking the damaged eye works. The device would contain an imaging detector with hundreds of pixels coupled to microscopic stimulating electrodes. “If light forms an image on the detector, then the result will be electrical stimulation of the retina in the shape of this image. The stimulated cells then send the information via the optic nerve to the brain. The imaging part of the system is based upon the technology used in any digital camera. When looking into someone's eyes, we can easily see several structures: A black-looking aperture, the pupil that allows light to enter the eye (it appears dark because of the absorbing pigments in the retina). A colored circular muscle, the iris, which is beautifully, pigmented giving us our eye's color (the central aperture of the iris is the pupil). This circular muscle controls the size of the pupil so that more or less light, depending on conditions is allowed to enter the eye. Eye color, or more correctly, iris color is due to variable amounts of eumelanin (brown/black melanins) and pheomelanin (red/yellow melanins) produced by melanocytes. More of the former is in brown eyed people and of the latter in blue and green-eyed people. The Melanocortin-1 Receptor Gene is a regulator of eumelanin production and is located on chromosome(MCIR) 16q24.3. Point mutations in the MCIR gene will affect melanogenesis. The presence of point mutations in the MCIR gene alleles is a common feature in light skinned and blue/green eyed people a transparent external surface, the cornea that covers both the pupil and the iris. This is the first and most powerful lens of the optical system of the eye and allows, together with the crystalline lens the production of a sharp image at the retinal photoreceptor level. The "white of the eye", the sclera, which forms part of the supporting wall of the eyeball. The sclera is continuous with the cornea. Furthermore this external covering of the eye is in continuity with the durra of the central nervous system.