Distance-Based Shared Control for Vitreoretinal Surgery

The fragility of ocular tissues combined with the limited surgical workspace demands precise instrument control and focus, making sensor-integrated robotic systems a promising solution. In this paper, we introduce a surgical system for telemanipulated endolaser photocoagulation that leverages instrument-integrated optical coherence tomography (iiOCT) for accurate distance measurement. We have developed a controller that maintains a specified instrument-to-retina distance, complemented by haptic shared control to assist the ophthalmic surgeon throughout the procedure. We conducted a pilot study involving 12 participants, including an expert vitreoretinal surgeon, to evaluate the system's performance across three levels of user assistance. The distance-based controller demonstrated a significant improvement in axial precison compared to telemanipulated trials, achieving a mean error of 4μm and a standard deviation of 69μm across all subjects. Experiments conducted on porcine eyes confirmed the feasibility of our approach on ex vivo tissues.