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Micro Eye Chips:

For the record
Science &
Women and Men
Micro Eye Chips
M. H. Panhwar
Information Technology
Navigation systems for business websites
Isra University
Eradicating the corruption

From Diana J. Choyce
Dec 20 - 26, 1999

Science and Technology have grown so fast, that the lines between them have been crossing more and more. But this is a good thing because in co-operation the two have made many incredible advances for man and his environment. Recent research has made some remarkable breakthroughs in helping the blind. Though it will be quite some time before a full cure is found, these advances come as a gift to those who can't see. In a dark world, even a shadow or shade of light is better than nothing at all.

Our eyes work similar to that of a camera. The lens focuses images onto the retina which stimulates special nerve cells called retinal ganglions. They then send the information on to the optic nerve which is connected to the brain. That is where the picture of what we are seeing is developed. Over10 million people worldwide suffer from retinal degenerative diseases such as age-related macular degeneration (AMD) and retinitis pigmentosa (RP). In those with a healthy retina, photoreceptors start the signalling to the brain in response to light. These receptors are almost completely absent in those with RP or AMD. However many of the nerve cells remain active and attached. So the new approach is to replace photoreceptor function with electrical stimulation of these nerves.

The new technology uses a small video camera in a set of goggles to send images to the microchip fastened to the back of the retina. Electrodes on the chip form an image that can stimulate the retina and be "seen'' by blind people. An implanted chip, and its bank of 5000 solar cells, converts the light into electrical signals that travel through the optic nerve to the brain, and are interpreted as an image. Currently the device displays only black and white images. "The beauty of it is that you're hooked up to the most powerful computer in the world, which is the human brain,'' said Dr. Mark Humayun, an ophthalmologist at Johns Hopkins Hospital's Wilmer Eye Institute. If planned animal and human trials are successful, the eye chip could be available in the next five years. Dr. Humayun says the prosthetic eyes are most useful for people who had sight at one time. Or those whose eyesight is lessening due to a degenerative eye disease.

The full system hasn't been tried with humans yet, but its various components have been undergoing tests for the last ten years. To date, seventeen patients have been fitted with the electrodes that are inserted directly into the retina. Many have been able to see light and a few have seen colours and light forms. One patient, 72-year-old Harold Churchey of Sharpsburg, Md., was able to recognize that a series of lighted dots formed the letter H. "From the very first time they put that first probe in my eye, I knew they were on the right track,'' he said. Harold and his brother Carroll are identical twins who are both legally blind. They are both participating as volunteers in the research. "There's a lot of blind people in this whole world, a lot of blind people, and through this procedure, if I can help them, I'm all for it. I can't wait till I can see my wife, and my son and my grandson", said Harold Churchey, crying.

These tests are done as short term transplants. They are done over a two to three hour period, and the implant is then removed. The implants are not biocompatable and are therefore not safe for more long term sessions. Scientists have made this a priority in their studies. The ability to leave the implants in for longer periods would help the research progress much more rapidly. The research teams involved in ongoing projects come from Massachusetts Institute of Technology (MIT), Johns Hopkins Hospital's Wilmer Eye Institute, and the University of Bonn in Germany.

There are several obstacles that remain to be solved. One is that the chip being used can only transmit an image of one hundred pixels or points. Scientists hope to develop one that will transmit 500 pixels or more. The other problem is a safe and secure way to attach the microchip to the retina. The fabric of the retina is as delicate as wet tissue paper. Also it must fit very tightly in order to prevent eye fluids from corroding it. And its power source must be strong enough but sensitive enough not to heat up and damage the eye. Scientists are saying that one shouldn't expect this to be a cure for blindness. "It would help their quality of life because they could make out the general forms of a spouse or a child,'' he said. "But it's not going to give them the kind of high-acuity vision that you and I have.''

What a wonderful feat of technology this could be, if the blind can be made to see again. Most people agree that losing their sight would be the worst handicap to live under. If man would spend a little more money on this type of research, instead of the more foolish, we could then say we are truly working towards man's good. To enable people like Harold and Carroll Churchey to see their families again would indeed be a great accomplishment.