Power for nuclear fragmentation in phacoemulsification -

Ans. is 'a' i.e., Ultrasonic o The ultrasound generating mechanism of the phaco handpiece causes the tip attached to it to vibrate rapidly back and forth. Tip excursion or stroke length is defined as the distance the tip displaces in the longitudinal direction at maximum power. Stroke length varies for different machines and normally ranges from 1.5-3.75 milli-inches. All phaco machines permit the user to alter phaco power and this is usually indicated as a percentage. Whenever the phaco power is set at 100 percent the stroke length is the maximum permissible for that machine. When the power is decreased by a given percentage, the stroke length also decreases. The frequency of a given handpiece is usually indicated in kilohertz (KHz). The frequency used most commonly is 40 KHz