Retinal implant partially restores blind patients’ sight

An electronic implant that partially restores blind people’s sight has helped three patients in Germany to see shapes and objects again.

The device, developed by Retinal Implant and the University of Tuebingen, could help change the lives of up to 200,000 people worldwide who suffer from blindness as a result of retinitis pigmentosa, a degenerative eye disease.

Research published in the journal Proceedings of the Royal Society B showed that the one subject was able to walk around a room unaided, as well as identify objects placed in front of him, read a clock face and differentiate seven shades of grey.

The research was carried out by Prof Eberhart Zrenner, founding director of Retinal Implant and director and chairman of the University of Tuebingen Eye Hospital.

‘The results of this pilot study provide strong evidence that the visual functions of patients blinded by a hereditary retinal dystrophy can, in principle, be restored to a degree sufficient for use in daily life,’ he said in the journal.

Subretinal implants directly replace light receptors lost in retinal degeneration. They use the eyes’ natural image-processing capabilities beyond the light-detection stage to produce a stable visual perception that follows the patient’s eye movements.

Retinal Implant’s device achieved greater levels of clarity than other similar devices because it had more light receptors.

Other implants – known as epiretinal implants – sit outside the retina. Because they bypass the intact light-sensitive structures in the eyes they require the user to wear an external camera and processor unit.

‘The present study…presents proof-of-concept that such devices can restore useful vision in blind human subjects, even though the ultimate goal of broad clinical application will take time to develop,’ said Zrenner.