A groundbreaking eye implant composed of platinum and silicone has shown encouraging signs in its efforts to restore sight to the blind.

After a year of the first patient trial researchers involved in the project say the artificial retina is proving effective.

Mark Humayun, professor of ophthalmology at the Keck School of Medicine of the University of Southern California, one of the institutions behind the experiment, was optimistic about the results.

'We have successfully completed enrollment and implantation of three patients in the trial,' he explained.

'And we have found that the devices are indeed electrically conducting, and can be used by the patients to detect light or even to distinguish between objects such as a cup or plate,' he added.

Patients are fitted with a tiny sliver of silicone and platinum studded with 16 electrodes.

The implant works by electrically stimulating a patient's remaining healthy retinal cells, which in turn pass visual information to the brain.

The implant is intended to stand in for damaged retinal cells in people suffering from blinding disease such as retinitis pigmentosa and macular degeneration.

Doctors operated on the first trial participant in February 2002 with the results being presented at a meeting of the Association for Research in Vision and Ophthalmology in Ford Lauderdale, Florida.