Development and experimental validation of a force sensing needle for robotically assisted retinal vein cannulations

Retinal Vein Occlusion is a common retinal vascular disorder which can cause severe loss of vision. Retinal vein cannulation and subsequent injection of anti-coagulant in the affected vein is a promising treatment. Given the scale and the fragility of retinal veins on one side and the surgeons limited positioning precision and force perception on the other side, this procedure is considered too risky to perform manually at the moment. The paper tackles the limited force perception problem. The development of a novel force sensing cannulation needle based on Fiber Bragg Gratings is reported. The design, the calibration method and the experimental characterization of the produced force sensor are discussed. The functionality of the needle is validated by measuring puncture forces during cannulations in a custom-made retina model.