Eyeworld

4 Optimizing machine settings for routine, complex, and femto phaco cases 4 Adjusting phacoemulsification settings during cataract surgery Figure 1. Stellaris segment removal settings presented by Bonnie An Henderson, MD Average lens Bottle height –135 cm Power – 40 Vacuum – 275 Pulse per second – 30 Duty cycle – 40% Dense lens Bottle height – 135 cm Power – 60 Vacuum – 290 Pulse per second – 70 Duty cycle – 60% Figure 2. Sculpting settings for WhiteStar Signature, presented by Kenneth L. Cohen, MD F luidics and ultrasound priorities change during phacoemulsification, depending on whether the surgeon is sculpting, chopping, or emulsifying the re- maining fragments of the nucleus. Experts share how they modify their settings on 3 major platforms to meet their changing needs during surgery. Stellaris PC Bonnie An Henderson, MD, clinical professor of ophthalmol- ogy, Tufts University School of Medicine, and in private practice with Ophthalmic Consultants of Boston, shared her practices with the Stellaris PC (Bausch + Lomb, Bridgewater, N.J.), a venturi ma- chine. During sculpting, power is reduced to decrease thermal ener- gy. As she sculpts, Dr. Henderson uses a bottle height of approx- imately 75 cm, which brings inflow into the eye. Her vacuum setting is 40 mm Hg; ultrasound, 50; pulses per second, 200; and duty cycle, 50%. "When you're sculpting, you want to be able to move your phaco tip smoothly through the nucleus without much resistance," she said. During segment removal or chopping, she increases her inflow, setting the bottle height at 135 cm. The vacuum is approx- imately 275 mm Hg, providing greater holding force. "Every time you want to increase your vacuum, you should increase your inflow," she said. Ultrasound power settings are reduced because she does not need to break through and sculpt the nucleus. Her pulse per second rate and duty cycle are also re- duced. Her bottle height is similar for average or dense cataracts, but she uses a slightly higher power and slightly increased vacuum for dense cataracts (Figure 1). "The pulse per second goes higher because I'm trying to emulsify the piece a little bit more and the duty cycle gets a little higher," she said. WhiteStar Signature Although the WhiteStar Signature Phacoemulsification System (Ab- bott Medical Optics, Abbott Park, Ill.) includes flow and venturi pump functions, Kenneth L. Cohen, MD, Sterling A. Barrett distinguished professor, Depart- ment of Ophthalmology, Univer- sity of North Carolina at Chapel Hill, only uses the flow pump. During the sculpt setting he uses for residents, the aspiration of flow rate and vacuum in the panel settings are fixed (Figure 2). Power has a linear setting controlled by the foot pedal. With the impale setting for chopping, residents have a slightly higher aspiration flow rate than for sculpting. "The vacuum is set much higher in a panel setting because you want to hold the piece firmly for chopping," he said. The power is linear to impale the nucleus. The Ellips function, employ- ing transversal energy, is used to emulsify the nuclear fragment. It is set with an occlusion mode, so aspiration flow rate is reduced as the vacuum is increased. In addi- tion, for the Ellips function they use the case mode. "When you have occlusion, it automatically lowers the vacuum for safety," he said. The epinuclear setting, using the occlusion mode, has a different threshold to reduce the aspiration flow rate as the vacuum increases. The aspiration flow rate and vacuum are linear, so they can be controlled with the foot pedal, he said. Infiniti and Centurion Lisa Park, MD, associate professor and associate director of residency training, Department of Oph- thalmology, New York University School of Medicine, compared the Infiniti Vision System and Cen- turion Vision System (Alcon, Fort Worth, Texas). When using the Infiniti for sculpting, vacuum and aspiration are low, she explained (Figure 3). However, during quadrant remov- al Dr. Park increases the vacuum and aspiration settings. She decreases the phaco power when she moves to the epi- nucleus so she doesn't eat through the pieces as quickly. In addition, she turns down the vacuum to hold the pieces more easily. continued on page 5

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