The challenge in performing traditional phaco chop is that the probe tip has to hold the nucleus with vacuum while the chop is propagated. Once the high vacuum is holding the nucleus there is a small window of time, perhaps 1 or 2 seconds, before the vacuum is lost as the nucleus crumbles. This can be challenging for resident surgeons to learn because of this time constraint. The crater chop technique is where a central crater is made in the nucleus and then the thick rim of nucleus is trapped between the chopper around the lens equator and the probe tip against the crater wall. This can be accomplished in foot pedal position 1 (infusion) without any vacuum and therefore without a time constraint. If you are struggling to learn phaco chop, try the crater chop technique.
