Let’s admit that phaco chop can be a tough technique to learn. It requires both hands to perform a different task at the same time and even more challenging, there is a time limit for performing the chop. With divide and conquer there is not a brief time window in which you must accomplish the nucleus separation after the grooves are sculpted. But with phaco chop, the holding power of the high vacuum will only last as long as the phaco tip is occluded. With a typical cataract, once 300 to 500 mmHg of vacuum is applied, the nuclear material begins to break down and suction is lost. This brief window of time where the vacuum level is highest will only last about 1 or maybe 2 seconds and that is the period in which the chop must be accomplished.
Placement of the instruments is very helpful in achieving this chop during the time window. The phaco probe should be placed in the nucleus just inside the sub-incisional capsulorhexis. The chopper tip placement depends on the technique: for horizontal chop it is placed around the lens equator whereas for vertical or combo chop, it is placed just inside the nasal capsulorhexis.
click to learn from this important video so that you can finally upgrade to quick chop: