Control Modes of Teleoperated Surgical Robotic System's Tools in Ophthalmic Surgery

TL;DR

In ophthalmic robotic teleoperation, control mode and scaling critically influence precision and safety due to the eye’s constrained environment. The study uses the IRISS platform with a VR retina simulator to compare Inside Control, which maps the master tip directly to the distal end inside the eye, against Outside Control, which maps motions proximal to the eye, testing Inside scaling factors of $5$, $10$, $20$, and $30$ while fixing Outside at $5$, analyzed via nonparametric tests. Inside Control consistently outperformed Outside across four vitreoretinal tasks, with larger Inside scaling ($20$ and $30$) yielding the greatest reductions in trajectory error and retinal penetration, though completion times were task-dependent. The findings advocate prioritizing Inside Control with higher scaling for high-precision ophthalmic procedures and motivate future work on adaptive scaling, curved-retina 3D visualization, and clinical validation to translate VR-simulated results to real-world settings.

Abstract

The introduction of a teleoperated surgical robotic system designed for minimally invasive procedures enables the emulation of two distinct control modes through a dedicated input device of the surgical console: (1) Inside Control Mode, which emulates tool manipulation near the distal end as if the surgeon was holding the tip of the instrument inside the patient's body; (2) Outside Control Mode, which emulates manipulation near the proximal end as if the surgeon was holding the tool externally. The aim of this research is to compare the surgeon's performance on these two modes of operation along with various scaling factors in a simulated vitreoretinal surgical setting. The console of Intraocular Robotic Interventional Surgical System (IRISS) was utilized but the surgical robot itself and the human eye anatomy was simulated by a virtual environment projected microscope view of an intraocular setup to a VR headset. Five experienced vitreoretinal surgeons and five subjects with no surgical experience used the system to perform four fundamental tool/tissue tasks common to vitreoretinal surgery: touch and reset; grasp and drop; inject; circular tracking. Results indicate that Inside Control outperforms Outside Control across multiple tasks and metrics. Higher scaling factors generally performed better, particularly for reducing trajectory errors and tissue damage. This improvement suggests that larger scaling factors enable more precise control, making them the preferred option for fine manipulation. However, completion time was not consistently reduced across all conditions, indicating that surgeons need to balance speed and accuracy based on surgical requirements. By optimizing control dynamics and user interface, robotic teleoperation has the potential to reduce complications, enhance dexterity, and expand the accessibility of high precision procedures to a broader range of practitioners.

Figures (11)

• Figure 1: Experimental Teleoperation Setup (a) Master Manipulator and Cockpit (controlled by the surgeon). (b) Closeup view of Master Manipulator input device (c) Closeup view of input device Gripper Mechanism
• Figure 2: Slave Manipulator (IRISS Robot)
• Figure 3: Coordinate frames for Inside and Outside control modes
• Figure 4: Teleoperation system structure
• Figure 5: Experimental setup showing the surgical cockpit and master arm configuration