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EW SHOW DAILY 58 Monday, May 9, 2016 limited effect, even if extenders are used to elevate the bottle higher than the phaco machine would usually allow. "As the nuclear pieces are being removed there is a very dynamic change in the intraocular pressure and therefore that is not as well compensated completely if you are just using elevation of the bottle as your strategy to countering surge," Dr. Basti said. Instead, active fluidics provid- ed by some phaco machines pairs microprocessors and sensors to esti- mate the IOP on an ongoing basis, provide feedback to the pump, and actively pump fluid into the anterior chamber. "The downside of active fluidics is the relatively short duration that it takes for a surge to be created," Dr. Basti said about the less than 100 milliseconds surges take to form. "Therefore, any intervention—both the sensing and the compensation —that active fluidics provides has to happen in that short period of time." Many software adjustments by the major phaco manufacturers have sought to address the problem. Additionally, narrower gauge tips many surgeons have moved to have reduced the outflow. Tubing chang- es also have sought to address this challenge. In addition to improved tech- nology, surgeons should use im- proved techniques to minimize the incidence of post-occlusion surge, Dr. Basti said. For instance, surgeons should ensure that their incisions have little leakage. "The more leak you have, the greater the impact of post-occlusion surge," Dr. Basti said. To reduce the heightened risk as later nuclear segments are removed, Dr. Basti urged surgeons to reduce the segment sizes and to engage the pieces further from the sides of the chamber. "That permits any intraocular pressure rise to not go all the way to the highest level," Dr. Basti said. EW Editors' note: This event was support- ed by education grants from Abbott Medical Optics (Abbott Park, Illinois), Alcon (Fort Worth, Texas), and Bausch + Lomb (Bridgewater, New Jersey). by Rich Daly EyeWorld Contributing Writer removal reaches the third or fourth quadrant. Bonnie Henderson, MD, Bos- ton, noted the surge challenge is in- herent in the tension between phaco machines being strong enough to remove the cataract but also able to leave everything in the eye stable and in control. "We hate surge, we don't like that immediate withdrawal of the piece and then the collapse of the anterior chamber," Dr. Henderson said. Post-occlusion surge is best avoided through better balancing of inflow and outflow. One of the first steps many sur- geons take to avoid the problem is elevating the bottle height on their phaco machine. "It's logical to expect that if the intraocular pressure is at a given level and you elevate the bottle then the intraocular pressure should go up because gravity is causing the fluid to flow in at a higher pressure level," Dr. Basti said. The downside to lifting the bottle to counter surge is that it has While some surge can occur when surgeons create their first chop, it's unlikely to cause a poste- rior capsule break. That is why Dr. Basti urged surgeons to use extra caution when their nuclear material T he danger of post-occlusion surge is greatest when most of the nuclear material has been removed from the eye, according to Surendra Basti, MD, Chicago. This insight on post-occlusion surge and other cataract surgery challenges was offered during an EyeWorld CME Educational Sympo- sium sponsored by the ASCRS Young Eye Surgeons Clinical Committee. "Post-occlusion surge is indeed a frustrating problem that can sig- nificantly alter the outcomes of our surgery," Dr. Basti said. The situation arises when the phaco tip is occluded by nuclear material while the pump is still rotating and builds vacuum in the tube proximal to the phaco tip. The occlusion causes partial collapse of the tubing, and when the occlusion breaks, there is rapid inflow into the tubing, which causes the tubing to expand. The rush of fluid and any nuclear material that's adjacent to the tip causes a shallowing of the anterior chamber. "That is occurring because there is an imbalance between inflow and outflow," Dr. Basti said. Dr. Basti noted that the risk of post-occlusion surge is most pro- nounced when the bag is relatively empty. "It's much less common when you have created that first chop," Dr. Basti said. Meeting Reporter When post-occlusion surge danger is greatest Dr. Basti explains the most dangerous time for post-occlusion surge to occur during cataract surgery. The winner of a hotel suite and transportation to and from the airport for the 2017 ASCRS•ASOA Symposium & Congress is Wasim Jaber, MD, Abu-Gosh, Israel. Today at 4:45 p.m. in the Exhibit Hall, a lucky participant's name will be drawn for the all-electric, deep blue Tesla Model S 90D.

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