An infusion sleeve for use with a phacoemulsification needle has a hollow body with an open end by which the sleeve is attachable to a handpiece and an open tip through which a phacoemulsification needle is passed. Irrigating liquid is directed from the handpiece through the sleeve. At least one discharge ports is formed in the sleeve to provide increased flow of irrigating liquid into the eye. The port or ports may differ in size, shape and positioning on the sleeve. At least one such port has a slit extending therefrom cutting through the sleeve and adapted to distend or open up under certain flow conditions, effectively increasing the cross-sectional area of the port available for flow. When flow conditions return to normal the slit returns to its “closed” position. Another such port is formed as a flap which opens and closes responsive to the flow of the irrigating liquid.
