EyeWorld India December 2018 Issue

Hard chop Soft slice Crack ergonomics: The long axis of the trench should bisect the surgeon’s instruments, cracking the nucleus from the bottom. Source (all): Richard Packard, MD tip, which has been buried in the middle of the nucleus. Dr. Packard recommends ei- ther a sculpt vacuum for medium nuclei or high vacuum for hard ones with vertical chop. Minimal vacuum is required for a hori- zontal chop. Medium cataracts are best broken down with a soft chop technique. To avoid going straight through a medium nu- cleus but obtaining an adequate hold to chop, he recommends using a relatively low, sculpt- ing vacuum setting of 75 mmHg to bury the phaco tip. Once the vacuum builds enough to gain purchase and reach full occlusion, chopping can begin from the periphery toward the center of the nucleus. Hard cataracts entail certain surgical considerations due to the lack of a red reflex and the possi- bility of fibrotic capsules or tense and swollen capsular bags. “There can be a small, mobile, often hard nucleus, or a large, dark, and hard nucleus, especially in older patients. The effect of advanced cataract on other ocular tissues is important to understand,” Dr. Packard said. “Hydrodissection of hard nuclei is usually easy, as there is less cortex holding the nucleus. White chalky cataracts are usually brittle and easy to chop. Multiple separations are important with dense brown cata- racts, using high vacuum with the phaco tip well buried to give good traction on the nucleus. Moderate flow will control nuclear pieces and avoid turbulence that might shoot pieces against and damage the endothelium during segment removal. The posterior plate can be quite rubbery and needs to be broken down carefully. Usually, there is no epinucleus in these cases, but the posterior capsule still needs to be protected. The use of a dispersive viscoelastic throughout nuclear removal will protect both the endothelium and the posterior capsule. A modified soft shell technique is used where- by the dispersive OVD is used at the outset to fill the eye. After hy- drodissection, the cohesive OVD is injected onto the top of the an- terior capsule to push the disper- sive against the endothelium. At the beginning of phaco, the cohe- sive is aspirated before using any ultrasound power. This will help to avoid wound burn. Using the dispersive OVD above and below the nuclear pieces will protect the ocular structures and hold these pieces in place for easier removal and less turbulence.” EWAP Editors’ note: Dr. Packard has no financial interests related to his com- ments. Contact information Packard: mail@eyequack.vossnet. co.uk Breaking down – from page 43 Surgeons should be comfortable mixing chopping approaches as the situation demands here, a soft chop. 46 EWAP CATARACT/IOL December 2018