Retinal implant trial expands

The Phase I three-year feasibility study of the Argus II Retinal Implant for Retinitis Pigmentosa (RP) will be expanded to enrol more patients in Europe, according to an announcement from Second Sight Medical Products, the implant's manufacturer. The multicentre trial is currently underway in Europe (Geneva, Paris and London), the United States and Mexico, and Second Sight is seeking FDA approval to expand the US arm of the trial. The Argus has so far been implanted into 17 subjects.

Preliminary results from the study, presented at the American Society of Retinal Specialists (ASRS) meeting in Hawaii, were positive. Patients who had been enrolled for a mean of 14 months demonstrated few serious adverse events, and no device failures, although one device was explanted due to adverse events. Study subjects were usually able to locate a door 20 feet (6.1 metres) away, and to walk to the end of a 20 foot line drawn on the floor.

Sixty electrodes, which conduct information acquired from an external camera to the retina, provide a rudimentary form of sight (motion and light and dark) to implanted subjects. The first generation of the implant, the Argus 16, comprised 16 electrodes and was tested in six RP patients between 2002 and 2004; the next generation device, currently under development, will have 1000 electrodes, allowing facial recognition. Although the implant is designed to be worn throughout the subject's life, it can also be removed safely.