Bionic eye gives blind man sight
Updated: 06:38, Friday May 4, 2012
A blind man in Britain has had a bionic eye implant that gives him rudimentary vision.
Chris James, who had been totally blind for more than 20 years, is the first British patient to be fitted with a digital chip similar to those used in mobile phone cameras.
Sky News was present during the operation and, later, when the chip was switched on.
‘I’ve always had that thought that one day I would be able to see again,’ he said.
‘This is not a cure, but it may put the world into some perspective.
‘It’ll give me some imagery rather than just a black world.’
Surgeons at Oxford’s John Radcliffe Hospital and King’s College Hospital in London are testing the implant in a clinical trial of up to 12 patients with retinitis pigmentosa.
The inherited eye disease destroys the retina – the ‘seeing’ part of the eye that is equivalent to a film in an old camera.
Around 25,000 families in Britain are affected by the condition, for which there is no treatment.
Surgeons in Oxford fitted the chip beneath Chris’ retina in a complex eight-hour operation.
Professor Robert MacLaren, professor of ophthalmology at the University of Oxford, said the success of surgery was a ‘great relief’.
‘Chris is doing extremely well,’ he said.
‘With the first operation, with the new technology and the complexity of everything, we are all absolutely delighted with the result.’
A second patient has since been fitted with the chip and is also responding well.
The sensor, designed by the company Retina Implant, is just 3mm square and packed with 1,500 pixels.
Light falling on the pixels is converted into an electrical signal that is picked up by nerves and transmitted to the visual processing region of the brain.
Patients see a grainy, black and white image.
And because the chip only covers a small part of the retina, their field of view is limited to a window the size of a CD case held at arm’s length.
But, because Chris has been blind for so long, his brain will take weeks to make sense of the images.
Although he can see the curve of a plate, he does not see the whole circle.
Professor MacLaren said: ‘The image is fragmented.
‘A circle may be perceived as two half circles, or even four quadrants, perhaps in different parts of space. What the brain needs to learn to do is put that back into one single object.
‘It is repeating in many ways what we all did when we learned to see in early childhood.’
Professor MacLaren said future generations of the chip are likely to be bigger, to widen the field of view, and have greater resolution.
The technology could be a cost-effective alternative to guide dogs, which cost GBP50,000 to GBP75,000 to train.
The chip is likely to be suitable for several hundred patients with retinitis pigmentosa.
In future it could be used to restore sight in patients with macular degeneration, a common disease in the over-65s.
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