This article is more than 5 years old. Information may no longer be current.
Publication Exclusive: Horizontal phaco chop makes cataract surgery more efficient with less ultrasonic energy
Click Here to Manage Email Alerts
Learning phaco chop is a straightforward transition for experienced surgeons who use the divide-and-conquer technique.
More than 20 years ago, Dr. Kunihiro Nagahara described the technique of phaco chop, which transformed cataract surgery by making it more efficient. His idea was simple: Use mechanical energy to break the cataract nucleus into smaller pieces instead of using the standard divide-and-conquer technique. Phaco chop requires less ultrasonic energy to disassemble the nucleus, and that means less damage to the delicate corneal endothelial cells, which makes for less inflammation and a faster postoperative recovery.
About phaco chop
Although the technique seems difficult, it is actually surprisingly simple to learn. Despite this reasonable learning curve, many cataract surgeons have not adopted this technique. During the course of the past 15 years, I have taught phaco chop to resident surgeons as part of their surgical training. Surgeons who currently use the divide-and-conquer technique are already adept at having a second instrument in the eye for the cracking portion of the nucleofractis technique. Learning phaco chop is a straightforward transition for these experienced surgeons.
The classic Nagahara technique is a horizontal chop, which means that the principal plane of movement is horizontal, parallel to the iris and lens surface. This is different from a vertical chop technique, whereby the goal is to propagate a crack vertically, toward the posterior capsule. For this article we will focus on the horizontal chop, which is suited to a wide range of nuclear densities and works well with most chopping instruments.
The only additional instrument that is needed is the chopper. This instrument has a tip that is just a few millimeters long in order to avoid touching the posterior lens capsule when the chopper is placed at the nucleus equator. The phaco platform settings must be adjusted so that the phaco probe is able to securely hold the cataract nucleus as the chopper divides it. This means that the vacuum level should be increased to 300 mm Hg to 500 mm Hg, depending on the size of the phaco tip, with a larger tip requiring less vacuum pressure than a smaller one. The flow rate and the bottle height/infusion pressure should be balanced and at a moderate range in order to facilitate nuclear fragment removal. Ultrasonic phaco power depends on the density of the nucleus, with a denser nucleus requiring more power.
Click here to read the publication exclusive, Back to Basics, published in Ocular Surgery News U.S. Edition, April 25, 2015.