Abstract: A surgical instrument provides improved precision and performance for use in highly intricate surgeries such as vitrectomy which frequently involves removing dense vitreous base firmly adherent to the retinal surface. The instrument includes two concentric tubes, an outer tube having ports near the closed end, and a slidable inner tube which fits snugly inside the outer tube. The inner tube includes a sharp cutting edge formed on one end that slides back and forth across the ports to cut vitreous, and an axial passage to pass the cut portions of vitreous. Such a surgical instrument maintains highly effective and accurate cutting device for removing vitreous without cutting into the retina.