An FBG Based 2-DOF Force Sensing Intraocular Lens Positioning Hook for Cataract Surgery

Intraocular lens (IOL) implantation is essential in cataract surgery. Intraocular lens positioning hook is used for position adjustment and accurate implantation of the IOL during the surgery. Effective force feedback of intraocular lens positioning hook can provide surgeons with imperceptible force information that will contribute to the accurate IOL implantation. Thus, accurate and effective force feedback is important for a hook. This letter presents an FBG based 2-DOF force sensing intraocular lens positioning hook for cataract surgery. In order to isolate the adhesive from human tissues, a layer of titanium coating has been plated on the adhesive surface through magnetron sputtering. The sensing performances of the hook have been tested. Calibration experiments demonstrate measurement sensitivities of 8.1 pm/mN and 7.4 pm/mN for $F_{x}$ and $F_{y}$ measurements, respectively. The linearities for $F_{x}$ and $F_{y}$ are 0.9997 and 0.9995, and the cross coupling on the $F_{x}$ and $F_{y}$ measurements are less than 0.8% full scale (F.S.) and 0.9% F.S., respectively. Moreover, the applicability of the proposed hook under steam sterilization environment has also been researched. The result indicates that the proposed hook can realize effective force feedback and valid isolation of the adhesive after repeated steam sterilization.