Eyeworld

EW CATARACT 46 Text goes here and separating." The sharp vertical chopper is embedded in the nucleus near the end of the phaco tip, which has been buried in the middle of the nucleus. Dr. Packard recommends either a sculpt vacuum for medium nuclei or high vacuum for hard ones with vertical chop. Minimal vacuum is required for a horizontal chop. Me- dium cataracts are best broken down with a soft chop technique. To avoid going straight through a medium nucleus but obtaining an adequate hold to chop, he recommends using a relatively low, sculpting vacuum setting of 75 mm Hg 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 cen- ter of the nucleus. Hard cataracts entail certain surgical considerations due to the lack of a red reflex and the possibil- ity 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 under- stand," Dr. Packard said. "Hydro- dissection 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 cataracts, 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 endotheli- um during segment removal. The posterior plate can be quite rubbery and needs to be broken down care- fully. 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 whereby the dispersive OVD is used at the outset to fill the eye. After hydrodis- section, the cohesive OVD is inject- ed onto the top of the anterior cap- sule to push the dispersive against the endothelium. At the beginning of phaco, the cohesive 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." EW Editors' note: Dr. Packard has no finan- cial interests related to his comments. Contact information Packard: mail@eyequack.vossnet.co.uk Breaking continued from page 45 " In order to be a complete phaco surgeon, a variety of alternate techniques are required to deal with nuclei of differing densities: soft, medium, and hard. " —Richard Packard, MD

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