Blindness, the most severe form of visual impairment, deprives people the ability to move about unaided. It is the most feared ailment in the present world. The leading causes of chronic blindness include cataract, glaucoma, age-related macular degeneration, corneal opacities, diabetic retinopathy, trachoma, and eye conditions in children (e.g. caused by vitamin A deficiency). Artificial vision has been a challenging task for the opto bionics. But now, a limited form of artificial vision is a reality. In this paper we present the various forms of artificial vision available for the blind in detail.
The Biomedical Instrumentation is the field in which various solutions for the medical problems is served. Linking electronics and biotechnology, the scientists has made the commitment to the development of technology that will provide or restore vision for the visually impaired around the world. Several investigations are being carried out on 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. We will discuss about the various development of artificial vision system, the concepts of artificial silicon retina, MARC (multiple artificial silicon retina chipset),and finally advancements and scope of this in future. ORIGIN OF ARTIFICIAL VISION:
Artificial-vision researchers has taken inspiration from another device, the cochlear implant, which has successfully restored hearing to thousands of deaf people and smart pacemakers which keeps heart beat rhythm normal. The eye is one of the most amazing organs in the body. Before we understand how artificial vision is created, it's important to know about the important role that the retina plays in how we see.
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, which interpret the message and send it to the brain through the optic nerve where images are formed, so with out them we are blind . There are a number of retinal diseases that attack these cells, which can lead to blindness. The most notable of these diseases are retinitis pigmentosa 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. RETINITIS PIGMENTOSA
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 TYPES OF ARTIFICIAL VISION:
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 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. There are mainly two types of artificial vision systems available at present, 1. ARTIFICIAL SILICON RETINA (ASR).
2. MULTIPLE UNIT ARTIFICIAL SILICON RETINA CHIPSET (MARC). ARTIFICIAL SILICON RETINA:
The ASR is an extremely tiny device. It is a silicon chip 2mm diameter and 25 microns thick, less than the thickness of a hair. It contains around 5000 microscopic solar cells called ‘micro photodiodes’ each will have its own stimulatory electrodes. These micro photodiodes converts...