Advanced Handheld Micro-Surgical System using an Hall Sensor and a Magnet Trocar for Retinal Microsurgery

Diseases affecting the retina, such as retinal detachment, diabetic retinopathy, and macular degeneration, are significant contributors to blindness globally, with a substantial risk of vision loss among those afflicted. Surgical treatment of these conditions is complex due to the delicate nature of retinal tissue and the challenges posed by involuntary hand movements. While existing methods aim to compensate for hand tremors using sensor-based systems, they are hindered by limitations in accurately tracking retinal surface movement during surgery, particularly in response to patient movements under anesthesia. To address these issues, this study proposes a novel handheld micro-surgical tool equipped with a 1-degree of freedom (DOF) mechanism and a 3-axis Hall sensor to mitigate physiological hand tremors effectively. By utilizing magnetic flux density measurements, the tool can pinpoint the position of a magnet embedded within the surgical instrument, enabling precise tremor compensation without reliance on a global coordinate system. The design incorporates a piezoelectric (PZT) linear actuator and a Hall sensor for compactness and sensitivity. Optimization of the magnet’s dimensions through simulation ensures optimal sensor performance. Experimental validation using artificial and ex-vivo porcine eye models demonstrates the tool’s effectiveness in reducing hand tremors, suggesting potential enhancements in the safety and accuracy of retinal surgeries. For the desired positions from 4000 µm to 1000 µm, the RMS error of the synthetic eye model and porcine eye decreased from 71.10 µm to 33.27 µm and 71.36 µm to 33.39 µm, respectively.