IRISS Teleoperated Surgical System

• IRISS Teleoperated Surgical System is a robotic platform for precise ophthalmic and minimally invasive intraocular surgery, featuring advanced control and scalable motion.
• It employs two control modes—Inside Control for direct telemanipulation and Outside Control for conventional movements—optimizing surgical precision and minimizing tissue trauma.
• The system integrates a VR-based simulation environment and modular design to enhance reproducibility and performance benchmarking in experimental and clinical settings.

The IRISS Teleoperated Surgical System is a robotic platform developed for high-precision teleoperation in ophthalmic and minimally invasive surgery, with specialized support for intraocular procedures. The system is characterized by advanced control interfaces, robust telemanipulation design, and a modular architecture. Its recent validation in virtual eye surgery environments and the integration of scaling optimization distinguish its role among contemporary robotic surgical apparatus.

1. Control Paradigms and Modes

The IRISS system’s teleoperation strategies are defined by two core control modes: Inside Control and Outside Control(Wang et al., 18 Jul 2025).

• Inside Control: In this method, operator inputs on the master device directly map to the tool tip’s movement inside the eye. This enables point-to-point direct telemanipulation, closely simulating the sensation of physically holding the intraocular instrument.
• Outside Control: Here, the operator manipulates the gripper’s position outside the scleral entry point, mapping master motions through spherical transformations (pitch, yaw, insertion) to the tool tip. This mimics the conventional “handle-outside” usage seen in manual vitreoretinal surgery.

Experimental findings indicate that while Outside Control matches familiar manual strategies, Inside Control achieves superior performance—particularly in speeding completion times, reducing trajectory variance, and minimizing retinal penetration. Thus, for delicate intraocular tasks, Inside Control is generally favored when paired with appropriate scaling.

2. Scaling Factors and Their Implications

Scaling factors govern the sensitivity of the teleoperation interface, with the IRISS system supporting adjustable values per degree of freedom(Wang et al., 18 Jul 2025).

• Low scaling factors translate small master displacements to larger slave movements, favoring agility but amplifying noise.
• High scaling factors require larger physical input to generate equivalent slave movement, thus dampening mechanical noise and stabilizing precision micro-motions.

Empirical evidence demonstrates that higher scaling values (α = 20 or 30) in Inside Control result in reduced excessive tool trajectory, lower tissue penetration, and generally improved surgical precision across a range of vitreoretinal tasks (e.g., touch and reset, grasp and drop, injection, circular tracking). The optimal scaling, however, may need adjustment in relation to the task complexity; for example, very fine manipulation may demand different scaling than gross handling.

Mathematically, tool movement is mapped as:

$$dx^{\text{master}}_{4 \times 1} = \alpha_{4 \times 1} \cdot dx^{\text{slave}}_{4 \times 1}$$

with $\alpha_{4 \times 1}$ representing the scaling per axis, and rotational scaling often fixed to avoid disorientation.

3. System Architecture and Virtual Reality Integration

IRISS’s user interface centers on a surgical cockpit with dual master arms and a foot pedal (clutch/emergency stop)(Wang et al., 18 Jul 2025). An innovative design aspect is the replacement of conventional 2D monitoring with a VR interface. An Oculus Rift S headset projects a simulated stereo microscope view of the intraocular environment, rendering physical phenomena such as the retina’s curvature and procedural complications (e.g., simulated bleeding).

The system’s simulation environment, constructed using Microsoft C#, Blender, and Unity, provides strict control over task reproducibility and quantification, thus serving both as a research tool and as a framework for rigorous performance benchmarking.

4. Experimental Validation and Performance Metrics

The IRISS system has been validated in simulation by both expert vitreoretinal surgeons and engineers without surgical experience(Wang et al., 18 Jul 2025). Experiments were conducted using one master arm under standardized tasks, with the following metrics:

• Completion Time: Reflects efficiency; Inside Control (scaling 10–30) consistently outperformed Outside Control.
• Accumulated Trajectory: Measures the total path length of the tool tip; lower values denote better motion stability and reduced tissue trauma risk.
• Accumulated Penetration: Quantifies unintended sub-retinal contact.
• Task-specific metrics: Include average error and accumulated out-of-target path segment.

Results indicate that pairing Inside Control with high scaling leads to the shortest completion time and the lowest accumulated trajectory and penetration, particularly in tasks simulating injection and precise tracking. Data analysis uses non-parametric statistics (e.g., Wilcoxon Signed-Rank, Cliff’s delta effect size) to rigorously compare experimental conditions.

5. Implications for Surgical Practice and System Design

Optimizing both control mode and scaling factors is shown to be critical for operational safety and efficiency in IRISS-guided intraocular procedures(Wang et al., 18 Jul 2025).

Key implications include:

• Reduced tissue risk: High scaling dampens excessive micromovement, minimizing unintentional retinal impact.
• Enhanced precision: Fine control, especially using Inside Control, supports stable and accurate microsurgical maneuvers.
• Workflow adaptability: The modular design and VR interface allow flexible adaptation to additional surgical tasks or environments.

A plausible implication is that adaptive scaling strategies—potentially responsive to real-time task demands or feedback signals—could further enhance operator performance, tailoring control sensitivity dynamically as intraoperative context evolves.

6. Context in the Field and Future Prospects

The IRISS system’s telemanipulation strategies and scalable VR-enabled simulation place it at the forefront of digital surgical innovation. By empirically validating control paradigms and scaling effects in a VR environment, the system lays the groundwork for the next generation of robotic intraocular surgical systems.

The reported results inform future robotic platform design, advocating:

• User-adaptive control methods that maximize performance for both expert and inexperienced operators,
• VR-based training and prototyping for controlled experimental research,
• Safety mechanisms (hardware and software, including emergency clutch) for risk mitigation.

Continued research is likely to extend these findings toward integration with real-world robotic hardware, adaptive haptic feedback, and broader application domains within and beyond ophthalmology.