Safety Control Method of Robot-Assisted Cataract Surgery with Virtual Fixture and Virtual Force Feedback

Surgery is an effective means of treating cataracts and restoring vision. However, cataract surgery rate (CSR) in developing countries and regions is relatively low due to the lack of experienced high-level surgeons. In this paper, to reduce the reliance of surgery on physician experience and thereby increase CSR, a master-slave robotic system and safety control strategies with a virtual fixture and virtual force feedback are proposed to assist cataract surgery. First, the surgery is divided into four different stages with different robot control modes. Secondly, the virtual constraint area with virtual spring model in the operating stage is established, so that the doctor can distinguish the operation area where the end of the surgical instrument is located by feedback force. Thirdly, safety control algorithm guarantees that the surgical instrument strictly moves around the surgical incision point, which is regarded as a remote centre of motion, so that the cornea outside the incision point is not injured. Finally, the experimental results show that the proposed safety control strategy allows the robotic system to perform the procedure safely.