September 25, 2005.
Ahmedabad, September 25: An eye for an eye can, in a doctor's parlance, create magic. Especially for those who've never known the difference between sunrise and sunset.
Artificial vision can make the blind see what he's been trying to imagine, says this expert from Japan whose team has been conducting research on the subject since 10 years to convert the theory into reality. At the Renaissance Symposium 2005 - Retina and Vitreous - Dr Tohru Yagi, researcher and associate professor at Tokyo Institute of Technology, made an interesting presentation.
According to Yagi, visual images can be produced in brain by electrical stimulation of retinal cells. A layer of retinal cells can be stimulated using an electronic array that inputs electrical impulses. The cells then transmit the image through optic nerve to cells in the visual cortex to create a perception of an image.
''But it is not the vision we see. The image is in the form of dots - like the electric score board you see in a cricket stadium,'' says the 38-year-old.
There are 20 research groups across the world trying to break ground in this field using the principle.
Research in this area began in the US in the 1960s. At that time the implant device was in the skull.
Called cortical implant, it had electrodes attached to a cable which was attached to the video camera. The principle: Camera captures an image, sends it to the computer which processes it. This generates impulses which are sent to the electrodes in the device, which inturn stimulates neurons to get perception of the image.
Yagi and his teammates have designed an intraoccular device (with a chip which is connected to electrode array) that is much smaller in size (3 cm long and 5 mm wide) and can be fitted directly into the retina. Here, the signals between the camera and computer and the device are transmitted in a wireless way. Estimated to cost approximately US $ 100,000, the device, he says, is not the optimum solution.
''It is a bridge to biomedical techniques like retina regeneration and stem cell therapy which are still in stages of research. But till that becomes a possibility, artifical vision can be of good help to the blind.''
''Clinical trials on animals have proved successful. Our challenge is now to increase the number of dots (which form images). This can happen if we increase the number of electrodes and shrink these to fit into the present size of the device. And the number should be large enough to generate electricity that is required to stimulate the neuron. Now that is a task and we are working on devising a new technology,'' says Yagi.
''I've got 15 more years before I retire. And by that time I hope the artificial technology improves quality of vision by cent percent, though I know we can't be as perfect as God,'' he says
''India has very skilled doctors and the technology here is also advancing at a fast rate. If the situations permit, we would be at an advantage to collaborate with Indian enterprises,'' adds Yagi.
Source URL: http://cities.expressindia.com/fullstory.php?newsid=150261
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