Implanted chip allows blind people to detect objects
A man with an inherited form of blindness has been able to identify letters and a clock face using a pioneering implant, researchers say.
Miikka Terho, 46, from Finland, was fitted with an experimental chip behind his retina in Germany. Success was also reported in other patients.
The chip allows a patient to detect objects with their eyes, unlike a rival approach that uses an external camera.
Prof Eberhart Zrenner, of Germany's University of Tuebingen, and colleagues at private company Retina Implant AG initially tested their sub-retinal chip on 11 people. Some noticed no improvement as their condition was too advanced to benefit from the implant, but a majority was able to pick out bright objects, Prof Zrenner informed.
However, it was only when the chip was placed further behind the retina, in the central macular area in three people, that they achieved the best results. The chip works by converting light that enters the eye into electrical impulses which are fed into the optic nerve behind the eye. It is externally powered and in the initial study was connected to a cable which protruded from the skin behind the ear to connect with a battery.
This is by no means the only approach being taken by scientists to try to restore some visual ability to people with retinal dysfunction — what is called retinal dystrophy.