An incisional instrument and method of use for creating accurate, reproducible surgical incisions. An exemplary embodiment includes an incisional instrument configured for attachment to a patient's eye and for use performing arcuate limbal relaxing incisions (LRIs). The incisional instrument is made up of two coaxial, interconnecting pieces: a docking piece and a cutting piece. The docking piece includes a suction mechanism and is configured for being secured to a patient's eye just outside the corneal limbus. The cutting piece is configured to fit flush within the docking piece and includes cutting blades and one or more handles for rotating the cutting piece relative to the docking piece. When assembled, the cutting blades extend beyond the proximal end of the docking piece by a length equal to the desired depth of LRIs to be cut. The incisional instrument further includes measurement markings for properly positioning and measuring incisions.