A novel dual force sensing instrument with cooperative robotic assistant for vitreoretinal surgery

Robotic assistants and smart surgical instruments have been developed to overcome many significant physiological limitations faced by vitreoretinal surgeons, one of which is lack of force perception below 7.5 mN. This paper reports the development of a new force sensor based on fiber Bragg grating (FBG) with the ability not just to sense forces at the tip of the surgical instrument located inside the eye, but also to provide information about the interaction force between the instrument shaft and the sclera. The sclera section provides vital feedback for cooperative robot control to minimize potentially dangerous forces on the eye. Preliminary results with 2×2 degrees-of-freedom (DOF) force sensor and force scaling robot control demonstrate significant reduction of forces on the sclera. The design and analysis of the sensor is presented along with a simulated robot assisted retinal membrane peeling on a phantom with sclera constraints and audio feedback.