Variation of cross-chop technique
I read with interest the cross-chop technique described by Kim1 during which the chopper is used to make a horizontal chop in the heminucleus with the phaco probe bracing the fragment; the name comes from the “X” configuration caused by crossing the instruments. This technique is said to be a safe and consistent method of disassembling the lens without rotating the nucleus; it is particularly recommended for weak zonules. I agree this is an excellent technique and have been using it successfully to avoid rotating the nucleus when tackling complicated cataracts, such as the dense posterior polar cataract.
My technique2 differs in that I prefer dividing the nucleus by making a central trough in the dense nucleus rather than by a quick-chop technique. Using adequate ultrasonic power and slow motion avoids rocking the nucleus during the sculpting process. The advantage of additional space created within the capsular bag outweighs the minimal movement induced during the sculpting maneuver, as it enables the phaco tip to comfortably settle deeply between the heminuclei under direct visualization, facilitating the cross chop. This step also avoids excessive nuclear manipulation and displacement, which may contribute to zonular stress, especially when dealing with a dense nucleus.
Chopping the first quadrant nucleus into smaller pieces also reduces zonular stress when removing the fragment from the capsular bag. Besides making a cross chop, the lamellar chop, which separates the nuclear fragment along its lamellar cleavage plane,2 enabling the smaller core of the hard nucleus of a segment to be eased out of the capsular bag, is highly relevant to preserving compromised zonules
1. Kim DB. Cross chop: modified rotationless horizontal chop technique for weak zonules. J Cataract Refract Surg. 2009;35:1335-1337.
© 2010 by Lippincott Williams & Wilkins, Inc.
2. Chee SP. Management of the hard posterior polar cataract. J Cataract Refract Surg. 2007;33:1509-1514.