A Sensorized Ophthalmic Endo-illuminator for Intraocular Surgery

Unmet Need
Lack of force sensing is one of the most formidable technical challenges in retinal microsurgery. Incorporating high sensitivity force sensing into the ophthalmic tools has the potential to provide the surgeon useful force feedback and to enable safe robotic assistance.  Forces exerted in retinal microsurgery are generally well below the human sensory threshold.  75% of forces applied during in vitro retinal manipulation in porcine cadaver eyes are less than 7.5 mN, and only 19% of the events at this force level can be felt by the surgeons.  Large forces are undesired and can potentially damage the delicate retina. Incorporating force sensing capability into the ophthalmic instrument enables quantitative monitoring of force applied during retinal mircosurgery. It can be used to provide awareness of subtactile tool-tissue forces to the surgeon. The technology can also be incorporated into robotic systems to provide haptic feedback and motion guidance.
Technology Overview
integrate fiber optic sensors into the tool shaft, close to the tool tip, such that the sensors are located inside the eye when the tool is used to manipulate the eye tissue. We developed a family of two degrees of freedom (DOF) force sensing tools that can measure the transverse forces with 0.25 mN resolution.  The design provides a sub-millimetric 3-DOF force sensing instrument with integrated FBG sensors. In addition, a new flexure design improves the axial force sensing, and reduces crosstalk noise from the transverse force.
Stage of Development: 
Calibration and validation results demonstrate reliable measurement of the contact force as well as location of the sclerotomy. Preliminary experiments have been conducted to functionally evaluate robotic intraocular illumination.
 
Publications: 
Proc IEEE RAS EMBS Int Conf Biomed Robot Biomechatron. 2014 Aug; 2014: 252–258.

 

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