ANN ARBOR, Mich. (AP) — A few patients who have lost their sight due to a rare disorder are regaining some vision thanks to a procedure performed at the University of Michigan.

The Ann Arbor school's Kellogg Eye Center is the first such facility in the U.S. to implant an artificial retina since the U.S. Food and Drug Administration signed off on it last year.

Four such surgeries have been performed at Michigan. A fifth is scheduled for next month.

Patients get the "bionic eye" system. It includes a small video camera and transmitter mounted on a pair of glasses. Images from the camera are processed into electronic data that are wirelessly transmitted to electrodes implanted into the patient's retina.

The surgery gives those with retinitis pigmentosa the ability to see shadows and shapes.