a phacoemulsification instrument that significantly reduces infusion fluid leakage by providing a silicone sleeve with a built in reinforcing member . also , the sleeve has only a single infusion hole in order to provide better infusion fluid flow without causing turbulence in the eye . in addition , the present invention provides either a valve or a variable aperture aspiration tube in order to regulate the aspiration rate . also , the present invention includes a single aspiration hole at the tip in order to amplify flow coming to the tip . to assist in cataract removal , the tip may be provided with a variety of different barrier and baffle configuration . a handpiece includes a variable capacity reservoir in the infusion line to account for surges in the aspiration line . the needle includes steps , angles and barriers to focus ultrasonic energy to aid in emulsifying nuclear tissue and to aid in pushing emulsified material in the direction of aspiration flow . a compressible sleeve is rotatably coupled to the handpiece to permit the handpiece and needle to be manipulated to a limited extent in the axial direction and rotated freely about the longitudinal axis while the sleeve remains stationary with respect to the cornea .