An optical force sensing element for microsurgical instruments and methods measures force F in three orthogonal directions and includes a monolithic cylinder structure, a cylindrical surface and a top surface that absorbs and transmits the force F. Three punch-like notches, all being parallel to the y-direction, are spaced apart along the z-axis and form two blades between the first and second notch and between the second and the third notch. Three channels parallel to the z-axis extend from the bottom surface to the top surface and cross the first notch while bypassing the other two notches. Three optical fibres, each fixed in one of the three channels, all entering the structure from the bottom surface, cross the first notch and end at or near the top surface while being interrupted in the first notch and forming two surfaces of each fibre that define a Fabry-Perot interferometric cavity.
