An Integrated High-dexterity Cooperative Robotic Assistant for Intraocular Micromanipulation

Retinal surgeons are required to manipulate multiple surgical instruments in a confined intraocular space, while the instruments are constrained at the small incisions made on the sclera. Furthermore, physiological hand tremor can affect the precision of the instrument motion. The Steady-Hand Eye Robot (SHER), developed in our previous study, enables tremor-free tool manipulation by employing a cooperative control scheme whereby the surgeon and robot can co-manipulate the surgical instruments. Although SHER enables precise and tremor-free manipulation of surgical tools, its straight and rigid structure imposes certain limitations, as it can only approach a target on the retina from one direction. As a result, the instrument could potentially collide with the eye lens when attempting to access the anterior portion of the retina. In addition, it can be difficult to approach a target on the retina from a suitable direction when accessing its anterior portion for procedures such as vein cannulation or membrane peeling. Snake-like robots offer greater dexterity and allow access to a target on the retina from suitable directions, depending on the clinical task at hand. In this study, we present an integrated, high-dexterity, cooperative robotic assistant for intraocular micromanipulation. This robotic assistant comprises an improved integrated robotic intraocular snake (I²RIS) with a user interface (a tactile switch or joystick unit) for the manipulation of the snake-like distal end and the SHER, with a detachable end-effector to which the I²RIS can be attached. The integrated system was evaluated through a set of experiments wherein subjects were requested to touch or insert into randomly-assigned targets. The results indicate that the high-dexterity robotic assistant can touch or insert the tip into the same target from multiple directions, with no significant increase in task completion time for either user interface.