Calibration and Integration of B-Mode Optical Coherence Tomography for Assistive Control in Robotic Microsurgery

During retinal microsurgery, surgeons cannot adequately visualize subsurface anatomical structures. In our previous work, a customized B-mode optical coherence tomography (OCT) probe was integrated into an ophthalmic robotic system to provide depth perception. This paper presents new approaches for implementing and achieving real-time feedback and assistive robotic control based on B-mode OCT imaging. The robotic system was comprised of a parallel robot, a micro-injection tool, and a telemanipulation master interface. A method for calibrating the B-mode OCT image scaling and distortion was presented using thin plate splines. Determining the OCT scanning plane relative to the robot base frame is presented through experiments and analyzed for sensitivity. A dual-rate controller using low frequency OCT feedback and high frequency position servoing was presented and tested for accuracy and latency. Three-dimensional assistive telemanipulation virtual fixtures based on microscope and OCT feedback are presented. The experimental evaluation demonstrated following target anatomy and semi-automated micro-injection. These results present the key steps towards achieving an integrated system for OCT feedback control using a miniature intraocular B-mode probe.