SEP 2012

EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.

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22 EW NEWS & OPINION Cortical continued from page 21 September 2012 Figure 1. Anterior capsule is tented up by the cannula, fluid wave is moving posteriorly, and capsulorhexis is enlarged (arrows fluid wave) and creating a path of least resist- ance that may disallow later cortical cleaving hydrodissection. Once the cannula is properly placed and the anterior capsule is elevated, gentle, continuous irrigation results in a fluid wave that passes circumferen- tially in the zone just under the capsule, cleaving the cortex from the posterior capsule in most locations (Figure 1). When the fluid wave has passed around the posterior aspect of the lens, the entire lens bulges forward because the fluid is trapped by the firm equatorial cortical- capsular connections. The procedure creates, in effect, a temporary intra- operative version of capsular block syndrome as seen by enlargement of the diameter of the capsulorhexis (Figure 2). At this point, if fluid in- jection is continued, a portion of the lens prolapses through the capsu- lorhexis. However, if prior to pro- lapse the capsule is decompressed by depressing the central portion of the lens with the long arm of the can- nula in a way that forces fluid to come around the lens equator from behind, the cortical-capsular con- nections in the capsular fornix and under the anterior capsular flap are cleaved. The cleavage of cortex from the capsule equatorially and anteri- orly allows fluid to exit from the capsular bag via the capsulorhexis, which constricts to its original size (Figure 3), and mobilizes the lens in such a way that it can spin freely within the capsular bag. Repeating the hydrodissection and capsular de- compression starting in the opposite distal quadrant may be helpful. Adequate hydrodissection at this point is demonstrable by the ease with which the nuclear-cortical complex can be rotated by the cannula. Figure 2. Capsulorhexis is enlarged by the posterior loculated fluid pushing the lens forward Following at least two cortical cleaving hydrodissection injections and rotation of the lens, we then perform hydrodelineation.1,7 Hydrodelineation circumferentially separates the endonucleus from the epinucleus and facilitates mobiliza- tion of the endonucleus separate from the epinucleus. The epinucleus remains in the capsule and keeps the bag stretched throughout the proce- dure, thereby making it much more unlikely that a knuckle of capsule will vault anteriorly, occlude the phaco tip, and rupture. In addition, hydrodelineation reduces the size of the nucleus that has to be mobilized through disassembly and emulsifica- tion, thereby reducing the amount of energy into the eye. Circumferen- tial division reduces the volume of the central portion of nucleus removed by phacoemulsification by up to 50 percent. This allows less deep and less peripheral grooving and smaller, more easily mobilized quadrants after cracking or chop- ping. Hydrodelineation thus creates additional safety and reduces the invasiveness of the procedure. Once all of the endonucleus has been mobilized we address the epin- ucleus. The bevel of the phaco tip is now turned up and the epinuclear rim and roof are purchased distally, in foot position two, pulled centrally and then swept with the phaco nee- dle at a low power, in foot position three, to trim the roof and rim of the epinucleus. This is associated with mini-occlusion breaks and mini-surges, more pronounced with 19 gauge tips, which allow the cor- tex in that quadrant to flow over the rim of the epinucleus and into the phaco needle. The epinucleus is allowed to settle back and then is ro- tated twice more, and two additional quadrants of peripheral epinuclear Figure 3. Return of the capsulorhexis to its previous size after decompression of the capsule Source (all): I. Howard Fine, M.D. roof and rim are mobilized along with the cortex under them. The final quadrant of epinuclear rim is rotated distally, purchased with the phaco tip in foot position 2, and pulled centrally, while the second handpiece is used to push the floor of the epinucleus, distally, thereby creating anti-parallel forces that flip the residual floor and last quadrant of the epinuclear rim upside down within the confines of the anterior chamber, removing it from its prox- imity to the posterior capsule, as it is mobilized mostly by vacuum with low power bursts of ultrasound energy. If there is residual cortex, more common with smaller gauge phaco tips, we simply sweep the cortical as- pirator circumferentially around the capsulorhexis, port facing the fornix of the capsule, and easily bring the remaining fragments out. Because the connections to the capsule have previously been lysed by cortical cleaving hydrodissection, we rarely need to strip cortex centrally. If there are some fine strands of cortex still attached to the capsule, we find it efficacious to use a 0.2 mm aspira- tion port, compared to a 0.3 mm port, as it will occlude more easily. Prior to cortical cleaning hydrodis- section, the majority of capsule ruptures during phacoemulsification surgery occurred during aspiration of the cortex. EW References 1. Fine IH (1992) Cortical cleaving hydrodis- section. J Cataract Refract Surg 18(5):508- 512. 2. Faust, KJ (1984) Hydrodissection of soft nu- clei. Am Intraocular Implant Soc J 10:75-77. 3. Davison JA (1989) Bimodal capsular bag phacoemulsification: A serial cutting and suc- tion ultrasonic nuclear dissection technique. J Cataract Refract Surg 15:272-282. 4. Fine IH (1991) The chip and flip phacoemul- sification technique. J Cataract Refract Surg 17:366-371. 5. Gimbel HV (1991) Divide and conquer nucleofractis phacoemulsification: Develop- ment and variations. J Cataract Refract Surg 17:281-291. 6. Sheperd JR (1990) In situ fracture. J Cataract Refract Surg 16:436-440. 7. Fine IH, Packer M, Hoffman RS (2004). Hydrodissection and hydrodelineation. In Cataract Surgery: Technique, Complications and Management, 2nd edition, R Steinert, editor, IH Fine, HV Gimbel, DD Koch, RL Lindstrom, TF Neuhann, and RH Osher, associate eds., Saunders: Philadelphia, PA. Editors' note: This is a modification of Chapter 9 (pages 197-216), "Mini- mally Invasive Cataract Surgery," in the book Minimally Invasive Oph- thalmic Surgery published by Springer- Verlag Berlin Heidelberg, 2010. Contact information Fine: hfine@finemd.com EyeWorld factoid The estimated number of people visually impaired in the world is 285 million, 39 million blind and 246 million having low vision Source: World Health Organization

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