A medical device and method for eye surgery and method for illumination and fluid flow, particularly retinal surgery, combines a flow of infusing fluid and optical fiber illumination. The device uses a single strand of plastic optical fiber which extends through bores in a juncture device tube and needle cannula with sufficient clearance to permit the flow of the infusing fluid. The illuminating tip of the optical fiber is moved, during surgery, by loosening a cap of the junction device to release the optical fiber, moving the optical fiber within the junction device, and then re-tightening the cap to re-secure the optical fiber.