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The mature, brunescent nucleus is a challenge for all phaco surgeons.
"There are several keys to the successful management of challenging eyes, including visualization of the anterior capsule, fragmenting the nucleus with minimal stress, and protecting the posterior capsule and endothelium," said Dr. Steinert, the Irving H. Leopold Professor, chairman of the Department of Ophthalmology, and director of the Gavin Herbert Eye Institute, University of California, Irvine.
Visualize the anterior capsule
Capsule staining is a mainstay here, he said, and cited some precautionary notes for surgeons.
"Apparently, there's a significant trend toward people trying to save money compared [with] the commercial trypan blue dye by using compounded pharmaceutical products," he said. "You have to be careful of a couple of things if you do this.
"First, you'd better have proof that you wrote an individual prescription for each and every patient," Dr. Steinert added. "It is illegal to have mass production of a substance by a compounding pharmacy. They must do it on a prescription basis, per person."
Secondly, endophthalmitis related to this has been reported, so surgeons must take care to be very cautious in their trust in the compounding pharmacy's ability to deliver sterile product, he added.
Next, Dr. Steinert continued, surgeons must be sure to fragment the nucleus with minimal stress to the capsule and the zonules.
"These dense nuclei are very thick, and if you do chop, you will have to do one of two things," he said. "You will either have to use a longer chopper [because] the standard 1.25-mm length is not long enough to get down into the center of the nucleus, or, alternatively, you need to create a groove first with the ultrasound, like a candy bar groove that creates a weak line for cracking."
Dr. Steinert continued, "The more of the procedure you can complete in the center and away from the cornea, the better you will protect the cornea from the ultrasound. Also, less total energy is expended with lateral tip motion by using either the torsional or transverse modes that are available.
"We've all learned the hard way that the posterior part of a 4+ nucleus is really tough," he said. "It's been called leathery for a good reason.
"It's got strands that try to hold things together," he said. "Ideally, I'd love to flip these over, but it's very hard to do that without breaking the capsule."
Surgically, he advises the use of a chopping or hook type of instrument brought along the edge of the nucleus and then used to snap these strands parallel to the posterior capsule.