ABSTRACT
Phacoemulsification is comprised of two basic elements: (i) ultrasound energy is used to emulsify the nucleus, and (ii) a fluidic circuit is employed to remove the emulsate through a small incision while maintaining the anterior chamber (Fig. 9.1). This circuit is supplied by an elevated irrigating bottle which supplies both the fluid volume and pressure to maintain the chamber hydrodynamically and hydrostatically, respectively; anterior chamber pressure is directly proportional to the height of the bottle. The fluid circuit is regulated by a pump which not only clears the chamber of the emulsate, but also
provides significant clinical utility. When the phaco tip is unoccluded, the pump produces currents in the anterior chamber, measured in cc per minute, which attract nuclear fragments. When a fragment completely occludes the tip, the pump provides holding power, measured in mm Hg vacuum, which grips the fragment. In order to fully exploit the potential of a phaco machine the surgeon must understand the logic behind setting the parameters of ultrasound power, vacuum, and flow.
