An ophthalmic surgical system comprising: a vitrectomy probe comprising: a housing sized and shaped for grasping by a user; a cutter extending from the housing and being sized to penetrate and treat an eye of a patient, the cutter comprising: an outer cutting tube coupled to the housing, the outer cutting tube having an outer port formed therein, wherein the outer port is sized and shaped to receive tissue; an inner cutting member disposed within the outer cutting tube, the inner cutting member rotatable about a longitudinal axis thereof, wherein the inner cutting member includes a first cutting surface that rotates across the outer port to cut the tissue when the inner cutting member is rotated; characterised in that the vitrectomy probe further comprises a pneumatic vane actuator positioned within the housing, the pneumatic vane actuator coupled to the inner cutting member and configured to rotate the inner cutting member; wherein the pneumatic vane actuator reciprocates the inner cutting member such that the inner cutting member rotates in a first direction and in a second direction opposite the first direction, and wherein the pneumatic vane actuator is adapted to apply a first air pressure pulse to a first chamber of the pneumatic vane actuator to rotate the inner cutting member in the first direction, and a second air pressure pulse to a second chamber of the pneumatic vane actuator to rotate the inner cutting member in the second direction. a vitrectomy probe comprising: a housing sized and shaped for grasping by a user; a cutter extending from the housing and being sized to penetrate and treat an eye of a patient, the cutter comprising: an outer cutting tube coupled to the housing, the outer cutting tube having an outer port formed therein, wherein the outer port is sized and shaped to receive tissue; an inner cutting member disposed within the outer cutting tube, the inner cutting member rotatable about a longitudinal axis thereof, wherein the inner cutting member includes a first cutting surface that rotates across the outer port to cut the tissue when the inner cutting member is rotated; characterised in that the vitrectomy probe further comprises a pneumatic vane actuator positioned within the housing, the pneumatic vane actuator coupled to the inner cutting member and configured to rotate the inner cutting member; wherein the pneumatic vane actuator reciprocates the inner cutting member such that the inner cutting member rotates in a first direction and in a second direction opposite the first direction, and wherein the pneumatic vane actuator is adapted to apply a first air pressure pulse to a first chamber of the pneumatic a housing sized and shaped for grasping by a user; a cutter extending from the housing and being sized to penetrate and treat an eye of a patient, the cutter comprising: an outer cutting tube coupled to the housing, the outer cutting tube having an outer port formed therein, wherein the outer port is sized and shaped to receive tissue; an inner cutting member disposed within the outer cutting tube, the inner cutting member rotatable about a longitudinal axis thereof, wherein the inner cutting member includes a first cutting surface that rotates across the outer port to cut the tissue when the inner cutting member is rotated; characterised in that the vitrectomy probe further comprises an outer cutting tube coupled to the housing, the outer cutting tube having an outer port formed therein, wherein the outer port is sized and shaped to receive tissue; an inner cutting member disposed within the outer cutting tube, the inner cutting member rotatable about a longitudinal axis thereof, wherein the inner cutting member includes a first cutting surface that rotates across the outer port to cut the tissue when the inner cutting member is rotated; characterised in that the vitrectomy probe further comprises a pneumatic vane actuator positioned within the housing, the pneumatic vane actuator coupled to the inner cutting member and configured to rotate the inner cutting member; wherein the pneumatic vane actuator reciprocates the inner cutting member such that the inner cutting member rotates in a first direction and in a second direction opposite the first direction, and wherein the pneumatic vane actuator is adapted to apply a first air pressure pulse to a first chamber of the pneumatic vane actuator to rotate the inner cutting member in the first direction, and a second air pressure pulse to a second chamber of the pneumatic vane actuator to rotate the inner cutting member in the second direction.