At the moment, surgeons struggle curing a widespread eye disease known as retinal vein occlusion where clots obstruct the retinal vessels. Latter vascular disorder involves black spots in people's eyesight and lead eventually to blindness. A recent promising treatment consists in flushing a thrombolytic agent inside the clotted retinal vessels. The surgery implies puncturing vessels ranging from 50 to 400 microns diameter on the backside of the eye, namely the retina. Latest research succeeded in tackling several challenges around this operation: the surgeon's hand tremor and the high precision required amongst other requirements. Despite several breakthroughs, the surgeon only relies on a microscope to perform the surgery through the patient eye's lens, giving poor depth perception to properly puncture the retinal vessels. This way, the surgeon is most likely to pierce through the vessel and inject the thrombolytic drug under the retina, which would endanger the person's eyesight. In this paper, we investigate the use of a novel bio-impedance sensor developed for eye surgery. Together with this new sensor, a detection algorithm has been developed to detect the puncture and double puncture events to give a feedback to the operator of the system. As far as we are aware of, such technology doesn't exist yet in eye surgery to tackle the depth perception question. This paper aims at demonstrating the benefits of this technology.

Retinal Vein Occlusion is a common retinal vascular disorder which can cause severe loss of vision. Retinal vein cannulation followed by injection of an anti-coagulant into the affected vein is a promising treatment. However, given the scale and fragility of the surgical workfield, this procedure is considered too high-risk to perform manually. A first successful robot-assisted procedure has been demonstrated. Even though successful, the procedure remains extremely challenging. This paper aims at providing a solution for the limited perception of instrument-tissue interaction forces as well as depth estimation during retinal vein cannulation. The development of a novel combined force and distance sensing cannulation needle relying on Fiber Bragg grating (FBG) and Optical Coherence Tomography (OCT) A-scan technology is reported. The design, the manufacturing process, the calibration method, and the experimental characterization of the produced sensor are discussed. The functionality of the combined sensing modalities and the real-time distance estimation algorithm are validated respectively on in-vitro and ex-vivo models.