This paper presents a robotic system that can achieve automatic positioning of surgical instruments for vitreoretinal surgery. Visual servoing can assist the surgeon in performing vitreoretinal surgery by automation of certain difficult tasks such as drug injection into blood vessels. Our system allows the surgeon to select a desired target location for the surgical instrument on a microscopic image. Thereafter, the robot moves the surgical instrument to the target location automatically. This system consists of tracking of the instrument in the microscopic image and a robust visual servoing loop. This paper presents the results from the implementation of visual servoing loop in this system.