The present invention related to an optical force sensing element for microsurgical instruments (22), for measuring force F in three orthogonal directions x, y, z, comprising a monolithic cylinder structure (1), a cylindrical surface (4) and a top surface (5) suitable to absorb and transmit the force F to be measured. The structure featuring three punch-like notches (6), all being parallel to the y-direction, spaced apart along the z-axis and forming exactly two blades (7) between the first and the second notch (6) as well as between the second and the third notch (6). The structure further comprises three channels (8) parallel to the z-axis, extending from the bottom surface (3) to the top surface (5) and crossing the first notch (6) while bypassing the other two notches (6) in the structure (2). The force sensing element further comprises three optical fibres (9), each fixed in one of the three channels (8), all entering the structure (2) from the bottom surface (3), crossing the first notch and ending at or near the top surface (5) while being interrupted in the first notch (6) building two surfaces (10, 12) of each fibre by defining Fabry-Perot interferometric cavities (13). The invention further relates to a microsurgical instrument comprising such an element and to a method for manufacturing such an element.