'Bionic eye' offers new hope of sight

American scientists hoping to give sight to the blind say they have successfully inserted silicon microchips in the eyes of three elderly men.

It was the second stage of a clinical trial being closely monitored by United States Government regulators and rival researchers around the world.

The device inserted, known as an artificial silicon retina or ASR, has been developed by a private research institute from Chicago called Optobionics, run by brothers Alan and Vincent Chow, in association with the University of Illinois.

The chip is smaller than a pinhead and narrower than a human hair. It is inserted beneath the retina, and the plan is for it to take over the light-sensing functions performed by a healthy human eye and permit people suffering from degenerative retinal disorders to make out shapes in a room or even read large-print books.

Optobionics announced that the operations - on a 72-year-old and a 59-year-old pair of twins - had been performed in two Chicago hospitals and that there were no initial signs of rejection. However, it would take several months to evaluate the success of the ASRs.

Just over a year ago, three other patients from the Chicago area had the device implanted. The Chows say one-year follow-up tests show that electrical signals are being sent to the patients' brains.

They have given no indication, however, of whether their eyesight has improved.

The Food and Drug Administration, which has given permission for the ASR to be inserted in up to 10 patients for experimental purposes, has to be briefed before the Chows can divulge results.

The search for a system of "bionic eyes", as this field of research has been dubbed, sounded like science fiction when first proposed a decade ago, but intensive research in Germany, Japan and the US has significantly raised hopes.

Surgeons insert the ASR by making tiny incisions in the eye and using a miniature cutting and vacuuming device to remove some of the gel in the middle of the eye and temporarily replace it with saline solution.

They then inject a tiny amount of fluid through the retina to create a small pocket behind, into which they insert the ASR.

- INDEPENDENT