BIONIC EYE : BIONIC EYE MADE BY:
Vinit gaure TOPICS COVERED : TOPICS COVERED What is Bionic eye?
History of Bionic eye?
Introduction to bionic eye.
How does a bionic eye allow blind people to see?
Optoelectronic retinal prosthesis.
Bionic eye expected by 2011 in Australia. Slide 3: WHAT IS BIONIC EYE ? A visual prosthesis or bionic eye is a form of neural prosthesis intended to partially restore lost vision or amplify existing vision. Slide 4: HISTORY OF BIONIC EYE Scientific research since at least the 1950s has investigated interfacing electronics at the level of the retina, optic nerve, thalamus and cortex. INTRODUCTION TO BIONIC EYE : INTRODUCTION TO BIONIC EYE This is what the world looks like to someone withmacular degeneration. INTRODUCTION TO BIONIC EYECONTINUED… : INTRODUCTION TO BIONIC EYECONTINUED… In the past 20 years, biotechnology has become the fastest-growing area of scientific research, with new devices going into clinical trials at a breakneck pace. A bionic arm allows amputees to control movements of the prosthesis with their thoughts. A training system called brain port is letting people with visual and balance disorders bypass their damaged sensory organs and instead send information to their brain through the tongue. Now, a company called Second Sight has received FDA approval to begin U.S. trials of a retinal implant system that gives blind people a limited degree of vision. INTRODUCTION TO BIONIC EYECONTINUED… : INTRODUCTION TO BIONIC EYECONTINUED… The Argus II Retinal Prosthesis System can provide sight -- the detection of light -- to people who have gone blind from degenerative eye diseases like macular degeneration and retinitis pigmentosa . Ten percent of people over the age of 55 suffer from various stages of macular degeneration. Retinitis pigmentosa is an inherited disease that affects about 1.5 million people around the globe. Both 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. INTRODUCTION TO BIONIC EYECONTINUED… : INTRODUCTION TO BIONIC EYECONTINUED… The second incarnation of Second Sight's retinal prosthesis consists of five main parts:
A digital camera that's built into a pair of glasses. It captures images in real time and sends images to a microchip.
A video-processing microchip that's built into a handheld unit. It processes images into electrical pulses representing patterns of light and dark and sends the pulses to a radio transmitter in the glasses.
A radio transmitter that wirelessly transmits pulses to a receiver implanted above the ear or under the eye
A radio receiver that sends pulses to the retinal implant by a hair-thin implanted wire
A retinal implant with an array of 60 electrodes on a chip measuring 1 mm by 1 mm How does a "bionic eye" allow blind people to see? : How does a "bionic eye" allow blind people to see? A magnified image of an eye with age-relatedmacular degeneration How does a "bionic eye" allow blind people to see? : How does a "bionic eye" allow blind people to see? The entire system runs on a battery pack that's 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. How does a "bionic eye" allow blind people to see? : How does a "bionic eye" allow blind people to see? 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 pigmentosa, 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." Optoelectronic Retinal Prosthesis : Optoelectronic Retinal Prosthesis ->Blindness is one of the most devastating consequences of disease. We develop electronic retinal prosthesis for restoration of sight to patients suffering from degenerative retinal diseases such as Retinitis Pigmentosa and Age-Related Macular Degeneration. In these conditions the photoreceptor cells slowly degenerate, leading to blindness. However, many of the inner retinal neurons that transmit signals from the photoreceptors to the brain are preserved to a large extent for a prolonged period of time. -> Electrical stimulation of the remaining retinal neurons can produce phosphenes - perception of light, and the first retinal implants involving a small number of electrodes (16 to 60) yielded encouraging results in patients with retinal degeneration. However, thousands of pixels are likely to be required for functional restoration of sight, such as reading and face recognition. Optoelectronic Retinal Prosthesiscontinued... : Optoelectronic Retinal Prosthesiscontinued... Development of a high resolution retinal prosthesis faces multiple engineering and biological challenges, such as delivery of information to thousands of pixels at video rate, placement of the electrodes in close proximity to the target cells, avoidance of fibrotic encapsulation of the implant, signal processing that compensates for the partial loss of the retinal neural network, and many others. Optoelectronic Retinal Prosthesiscontinued... : Optoelectronic Retinal Prosthesiscontinued... System Design:- Optoelectronic Retinal Prosthesiscontinued... : Optoelectronic Retinal Prosthesiscontinued... System Design:- Data stream from a video camera is processed by a pocket PC, and the resulting images are displayed on a liquid crystal microdisplay (LCD), similar to video goggles. The LCD corresponding to approximately 30 degrees of visual field is illuminated with a pulsed (0.5 ms) near-infrared (~900 nm) light, projecting the images through the eye optics onto the retina. The IR image is then received by the photovoltaic pixels in a subretinally implanted chip. Each pixel converts the pulsed light into a proportional pulsed bi-phasic electric current that introduces visual information into diseased retinal tissue. Retinal chip is approximately 3 mm in diameter, corresponding to 10 degrees of visual field. The 30 degree visual field is accessible by eye scanning. Optoelectronic Retinal Prosthesiscontinued... : Optoelectronic Retinal Prosthesiscontinued... Proximity of Electrodes to Target Cells:- Figure (a) Figure (b) Figure © Optoelectronic Retinal Prosthesiscontinued... : Optoelectronic Retinal Prosthesiscontinued... Proximity of Electrodes to Target Cells:- Figure (a):- Scanning Electron Micrograph of a lithographically manufactured array with pillars of 10 μm in diameter and 65 μm in height. Figure (b):- Histology of the RCS rat retina 6 weeks after implantation of a pillar array into a subretinal space. Tops of the pillars achieve an intimate proximity with the cells in the inner nuclear layer Figure (c):- Conceptual diagram of the photovoltaic pixels with pillar electrodes (1) penetrating into the inner nuclear layer. The return electrodes (2) are located in the plane of the photodiodes. ONGOING PROJECTS : ONGOING PROJECTS -> Argus Retinal Prosthesis:- Drs. Mark Humayun and Eugene DeJuan at the Doheny Eye Institute (USC) were the original inventors of the active epi-retinal prosthesis and demonstrated proof of principle in acute patient investigations at Johns Hopkins University in the early 1990s. -> Microsystem-based Visual Prosthesis (MIVIP):- Designed by Claude Veraart at the University of Louvain, this is a spiral cuff electrode around the optic nerve at the back of the eye. It is connected to a stimulator implanted in a small depression in the skull. The stimulator receives signals from an externally-worn camera, which are translated into electrical signals that stimulate the optic nerve directly. ONGOING PROJECTScontinued… : ONGOING PROJECTScontinued… -> Visual Cortical Implant:- ONGOING PROJECTScontinued… : ONGOING PROJECTScontinued… -> Visual Cortical Implant:- The basic principle of Dr. Sawan’s technology consists in stimulating the visual cortex by implanting a silicium microchip on a network of electrodes made of biocompatible materials and in which each electrode injects a stimulating electrical current in order to provoke a series of luminous points to appear (an array of pixels) in the field of vision of the sightless person. ->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. Boston Retinal Implant Project : Boston Retinal Implant Project Boston Retinal Implant Projectcontinued... : Boston Retinal Implant Projectcontinued... -> 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. Although the bionic eye will only help individuals that were born with functional eyesight, the implant is expected to considerably improve their lives. -> 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. ->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. Slide 23: Bionic Eye Expected By 2011 In Australia:- Head of the Macular Research Unit at the Centre for Eye Research Australia, University, Professor Robyn Guymer says the boost in funding will increase chances of delivering a bionic eye with such high resolution that it does more than simply differentiate between shadows and large objects, as current bionic eyes enable. India could be the next destination for clinical trials for the artificial retina referred to as the retinal prosthesis or bionic eye developed by Texas Instruments Incorporated (TI), a world leader in analog