Implanted eye chip in Germany gives blind man sight again

German scientists have pioneered a revolutionary new eye chip that will enable the blind to see again.

Professor Eberhart Zrenner of Germany’s University of Tuebingen and Colleagues at private complany Retina implant AG have recently fitted a sub retinal chip on 11 people suffering from varying degrees of inherited blindness with success.

Professor Zrenner said ‘This is proof of concept. In 1900, nobody knew if we would ever have powered flight, but then the wright brothers flew a couple of hundred metres and showed it was possible. We are in the same situation’

Among the patients are Finland native Miikka Terho, 46, who had lost sight as a teenager. He was able to identify letters and a clock face as well as different shades of grey. Terho, who was the most successful of the patients, was also able to identify cutlery and a mug on a table as well as walk around a room independently and approach people. Other patients whose condition of blindness was more developed did not have as good a result.

Surgery for each patient was completed in six hours and consisted of cutting a small flap in the retina and inserting a 3mm by 3mm chip which was connected via thin wire to an external battery on a necklace worn by the patients. The chip contains 1,500 light sensitive elements that replace defunct cells in the retina. These elements then send signals to the brain and help the patient differentiate light and darkness.

The chip is suitable for people with inherited conditions that effect the rod and cone cells in the retina such as retinitus pigmentosa (RP), and choroideraemia. RP is a degeneration of cells in the eye’s retina. Usually the symptoms begin in early childhood and progress onto night blindness, tunnel vision and eventually permanent blindness. The chip would not be successful in all cases of blindness, for instance where the optic nerve was damaged.

Terho said ‘Three or four days after the implantation, when everything was healed, I was like wow, there’s activity. Right after that, if my eye hit the light, then I was able to see flashes, some activity which I hadn’t had. Even having a limited ability to see with the chip, it will be good for orientation, either walking somewhere or being able to see that something is before you even if you don’t see all the tiny details of the object.’

British teams led in part by consultant retinal surgeon Robert Maclean at Oxford eye hospital will implant the chip in the first UK patients in a multicentre trial starting early next year.

Other eye experts are more sceptical of the eye chip. David Head, of the British RP society said ‘It’s really fascinating work, but it doesn’t restore vision. It rather gives people signals which help them to interpret.’

The prototype chip has now been removed from Terho but he has been promised an upgrade. The German science team are now creating a chip that will be completely internal, with power delivered through the skin via an external device that clips behind the ear.

by Adam Smyth