A device for performing at least one medical function on a user is proposed. The device has at least one medical functional element that is designed to perform the medical function. The medical function is selected from a diagnostic, a therapeutic and a surgical function. The device has at least one evaluation and control part that comprises at least one actuation component for controlling the medical function. The evaluation and control part has at least one casing and at least one battery receptacle. The battery receptacle comprises at least one electrical energy reservoir, more particularly at least one battery. The battery receptacle is designed to be opened irreversibly by the user for removing the energy reservoir.
