Retinal Prosthesis posts encouraging results in clinical trial
By Darren Quick
February 7, 2012
After receiving European market approval for its Argus II Retinal Prosthesis in 2011, Second Sight has published interim results of an international clinical trial showing encouraging results in blind patients suffering severe retinitis pigmentosa (RP) - a group of genetic degenerative eye conditions that leads to incurable blindness.
The Argus II captures video images using a miniature camera housed in the patient's glasses and converts them into a series of small electrical pulses that are wirelessly transmitted to an array of electrodes on the surface of the retina. These pulses are designed to stimulate the retina's remaining cells which send messages along the optic nerve to the brain. The brain is then able to perceive patterns of light and dark spots corresponding to which electrodes have been stimulated.
The multicentered, long-term, controlled clinical trial involved 30 patients who were implanted with the Argus II Retinal Prosthesis, which is the only retinal prosthesis in the world so far approved for sale in Europe. The patients' progress was followed for periods of between six months and 2.7 years and they underwent a series of visual acuity tests performed using computer monitors - square localization, direction of motion and grating visual acuity. The patients were also given two types of real-world orientation and mobility (O&M;) tests. These involved finding a door across a room and following a white line on the floor.
Results published in the journal Ophthalmology indicate significant improvements in the O&M; tasks, as well as improvements of 96 percent in object localization, 57 percent in motion discrimination, and 23 percent in the discrimination of oriented gratings.
Second Sight says the results demonstrate the reliability and efficacy of the Argus II and that the safety profile of the prosthesis is comparable to other ophthalmic devices and procedures.
"The Argus II can, quite simply, help the blind see," said Dr. Stanislao Rizzo, Director of the U.O. Chirurgia Oftalmica, Azienda Ospedaliero Universitaria Pisana of Pisa, who on October 29, 2011, became the first surgeon to implant Argus II following European market approval. "Having an approved device backed by significant clinical data is cause for great hope among those patients suffering from RP. There is finally a real solution that means that their vision can be partially restored, safely."
Source: Second Sight