(Left) Implant behind eye. (Right) Retinal scan showing the sensor chip in place. (via University of Oxford)
Diagnosed with retinitis pigmentosa, the first symptom was night blindness. A few years later, vision was drastically reduced. Finally, another disease brought complete blindness in the left eye and the inability to distinguish light on the right. Chris James, a fifty-four year old council worker in Wiltshire U.K., had his life completely changed by his complications. He said, "It’s something you have to come to terms with and make the best of what you’ve got."
Chris James's new eye was switched on for the first time. The digital circuits flood with electricity. James could see light against a black background for the first time in decades. The retinal implants were a success. "As soon as I had this flash in my eye, this confirmed that my optic nerves are functioning properly which is a really promising sign. It was like someone taking a photo with a flashbulb, a pulsating light, I recognized it instantly."
Chris James was one of the first patients (along with Robin Millar, a 60 year old music producer) suffering from retinitis pigmentosa to receive retinal implanted circuitry to detect light and images from a collaboration between the University of Oxford (UO) and the company "Retina Implants" form Germany. A team led by ophthalmology professor Robert MacLaren were able to help the patients regain some semblance of vision. As the patients continue to use the implants, their vision continues to improve. Currently, the patients can see light differences and basic shapes.
X-ray image of the complete system installed into Chris James. (via University of Oxford)
The implant is a 3mm square chip containing 1,500 light sensitive diodes. The chip is attached to the back of the eye where a signal can be sent between electrodes and the patient's optical nerves. The system is powered by an implanted power supply buried behind the ear, similar to some cochlear devices. Professor MacLaren explained that the sensor will "stimulate the overlying nerves to create a pixellated image." He continued, "Apart from a hearing aid like device behind the ear, you would not know a patient had one implanted. We are all delighted with these initial results. The vision is different to normal , and it requires a different type of brain processing. We hope, however, that the electronic chips will provide independence for many people who are blind from retinitis pigmentosa."
The U.K based trials will continue with 12 patients overall thanks to funding from the National Institute of Health Research and the Oxford Biomedical Research Centre.
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