The disclosure herein provides ophthalmic surgical systems, methods, and devices. In one embodiment, a handheld medical instrument for surgical procedures comprises a body having an exterior surface shaped to be held and manipulated by a human hand; a surgical tool extending from a distal end of the body; and a pressure-sensitive button for controlling operation of the surgical tool, the pressure-sensitive button comprising an actuation surface positioned adjacent the exterior surface of the body, the pressure-sensitive button further comprising a pressure detection device, the pressure detection device configured to enable output of a signal for controlling a function of the surgical tool, the signal being proportional to a position of the actuation surface.