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EW MEETING REPORTER 116 September 2017 Reporting from the Combined Ophthalmic Symposium (COS), August 11–13, Austin, Texas are constricted, is associated only with "anatomically perfect surgery," and may have symptoms that are uniocular despite similar anatomy. Negative dysphotopsia is likely multifactorial, she said, and can be prevented, relieved, or improved when the IOL optic edge overlies the anterior capsulotomy. The common pathway for negative dysphotop- sia is any in-the-bag IOL with the anterior capsulotomy edge overlying the optic. Surgical management of nega- tive dysphotopsia may be therapeu- tic or preventative. At the end of the session, Douglas Koch, MD, Houston, and Mitchell Weikert, MD, Houston, shared a number of cases, discussing IOL calculations. Dr. Weikert presented the case of a patient who had cataract sur- gery with a toric IOL and came back complaining of blurring and smear- ing of lights. The patient had been a high myope before surgery and still Dr. Donaldson discussed ultra- sound before sharing her tips for becoming a better phaco surgeon by decreasing phaco time and energy. She recommended using mechan- ical nucleus disassembly, less time on the foot pedal, decreasing the maximum phaco power setting, using phaco power modulation, and advanced power modulation. Nicole Fram, MD, Los Angeles, discussed dysphotopsia, covering positive and negative dysphotopsia. A dysphotopsia is a subjective, unde- sired optical image associated with otherwise uncomplicated cataract/ monofocal IOL surgery. Positive dys- photopsia (PD) includes light streak/ arcs, flashes, starburst, and shim- mering. Negative dysphotopsia (ND) may be described as a temporal dark shadow or "horse blinders." Negative dysphotopsia, Dr. Fram said, is stimulated by a temporal peripheral light source, may be blocked by the hand, may have worse symptoms when the pupils T o begin the session on cataract surgery, Kendall Donaldson, MD, Planta- tion, Florida, presented on phacodynamics, highlight- ing how to maximize settings. First, she spoke about the three principles of phaco, followability, stroke length, and using a minimal amount of power/energy. She went on to discuss fluidics and ultra- sound. The three purposes of fluidics are to maintain space, to create currents, and to keep things cool. Dr. Donaldson compared the two types of pumps. A peristaltic pump is flow based, the vacuum is created on occlusion of the phaco tip, the flow is constant until occlusion, and it drains into a soft bag. Meanwhile, a venturi pump is vacuum based, the vacuum is created instantly from the pump, the flow varies with the vac- uum level, and it drains into a rigid cassette. In the U.S., she noted, the peristaltic pump is most common. Reporting from the Combined Ophthalmic Symposium

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