A Shared Control Architecture for Vitreoretinal Surgery with Safety Guarantee Using Control Barrier Functions
Nicola Piccinelli, Federico Vesentini, Marius Briel, Ludwig Haide, Eleonora Tagliabue, Marco Pellegrini, Gernot Kronreif, Riccardo Muradore
AI summary
Problem
Vitreoretinal surgery demands micron-scale precision and constant depth awareness, yet existing robotic platforms rely on heuristic safety limits or lack formal, real-time guarantees to prevent retinal contact.
Approach
The method uses an instrument-integrated OCT to reconstruct the retinal surface in real time, then applies Control Barrier Functions to enforce a safe working band and provides proportional haptic feedback to guide the surgeon.
Key results
- CBF-based controller maintains tool position within a defined safety band above the retina
- Real-time 3D retinal surface reconstruction via iiOCT and radial basis function interpolation
- Ex vivo porcine eye validation demonstrates improved safety and depth tracking during vitreous shaving
- Proportional haptic feedback effectively guides operators to the optimal working distance
Why it matters
Provides a formal, real-time safety guarantee for delicate eye surgeries, reducing retinal damage risk and improving surgeon awareness for ophthalmologists and robotic surgery developers.
Abstract
Control Barrier Functions (CBFs) provide a pow- erful framework for enforcing real-time safety in control systems and have seen increasing applications in safety-critical domains, such as surgical robotics. In vitreoretinal microsurgery, where precision and tissue protection are crucial, we propose a shared control approach that leverages CBFs to maintain the robot’s end-effector within a safe zone above the retina. Using real- time 3D reconstruction from an instrument-integrated Optical Coherence Tomography (iiOCT) system mounted on the sur- gical tool, we define a safety band between two offset surfaces derived from the reconstructed retina. A hybrid controller drives the tool into the band when outside and then enforces forward invariance using a CBF-based quadratic program. Concurrently, haptic feedback proportional to the deviation from the band centre guides the surgeon toward the optimal working distance. We validate our method in ex vivo pig eye experiments, performing a simulated Vitreous Shaving (VS), showing improved safety and operator awareness.