Eyeworld

7 Supported by unrestricted educational grants from Abbott Medical Optics, Alcon Laboratories, and Bausch + Lomb Phacoemulsification settings for laser-assisted cataract surgery: Fluidics and pearls for success A s cataract surgery tech- nology evolves, sur- geons making the tran- sition to femto laser cataract surgery need to know how to adapt their phaco settings for venturi and peristaltic pumps for femto phaco. Venturi settings Keith A. Walter, MD, professor of ophthalmology, Wake Forest University, Winston-Salem, N.C., compared the features of the LenSx Laser System (Alcon, Fort Worth, Texas) and Catalys Preci- sion Laser System (Abbott Medical Optics, Abbott Park, Ill.). Surgeons can choose either a segmentation or cube option with LenSx or both options simultane- ously with Catalys, he said. "The Catalys goes out beyond the cap- sulotomy for your complete lens fragmentation and making the cubes," he said. "LenSx has a limit on how far out you can go based on the capsulotomy size." Femtosecond cases rotate and crack more easily, Dr. Walter said. "There's a little bubble layer that forms behind the lens in the Catalys cases between the epinucleus and cortex that makes that lens automatically rotate every time," he said. Because of the bubble layer, surgeons do not need to manage an epinucleus. With Catalys software, surgeons can customize their treatment, with segmentation and quadrants, sextants, and octants. "You can use softening patterns and change your cube size from 100 microns to 2,000 microns," Dr. Walter said. "I typically use 350 microns on most of my cases. If it's a denser lens, I might go down to 250 microns." With this lens treatment, surgeons use less ultrasound and phacoemulsification and more fluidics, he said. Dr. Walter likes the Whit- eStar Signature System (Abbott Medical Optics) with dual pumps for femto-treated cases. "I think you need to have different pumps, depending on whether cheese-wiring through, so having that off time gives me the control to pull that piece in slowly," she said. "Once I have engaged and gotten it away from the capsular crowding, I can go deeper into the third position of the foot pedal, engage more torsional ultrasound energy and disassemble that nuclear piece." With dense nuclei, she uses a slightly tighter grid pattern, which creates smaller cubes (Figure 1). "With the numerous femto-fragmented pieces, you often don't need to engage a lot of phaco energy. Also helpful is customizing the foot pedal to cre- ate greater excursion time in foot position 2, which will allow for more controlled aspiration of the pieces and is useful with laser-as- sisted cataract surgery as well as very soft lenses," she said. "When you're dealing with newer technology, there is a learn- ing curve," Dr. Yeu said. "Femto phaco has made cataract surgery more interesting, especially when you get to customize your patterns to best benefit patients." sular technique, surgeons can use a chop/cylinder or grid technique, she said. "But as a chop surgeon, the waffle or the grid fragmentation pattern is wonderful," Dr. Yeu said. "Of course, with the denser nuclei, it goes without saying, because there's ultimately going to be less ultrasound energy that is being transmitted into the eye." Dr. Yeu shared a video demonstrating cross-chop with a single cylinder and utilizing a "pre-chop" setting before sculpt- ing. The "pre-chop" setting has a slightly greater vacuum and less energy to first remove the central core delineated by the cylinder pattern. "When you debulk that cylinder, very little phaco is required, but it makes it easier to engage and split the rest of the nuclear pieces, and then you can go into your normal sculpt setting," she said. She uses a separate chop versus quad setting, with a linear burst and a fixed vacuum when she engages the nucleus. "I want to hold on really well, but I want to continue holding on without you want to hold a quadrant or try to grab a piece, versus venturi, where you want more followabili- ty for those small fragments." In a typical case, he uses the peristaltic mode for sculpting and to grab the first quadrant and may switch to venturi afterward. For a softer lens where he is working in the bag, he may remain in peri- staltic mode. With venturi, his goal is to prolapse the fractured nucleus out of the bag and allow the vacuum to do most of the work. "If you're getting too much surge, you can always change your vacuum, or you can also use a larger tip." Peristaltic extraction Elizabeth Yeu, MD, assistant pro- fessor, Eastern Virginia Medical School, and in private practice, Virginia Eye Consultants, Norfolk, Va., suggested the cross-chop/ single cylinder pattern for those beginning with laser-assisted cata- ract surgery. She explained that the chop/cylinder is useful for divide and conquer surgeons and for softer cataracts. With a supracap- Figure 1. Nuclear fragmentation pattern created by the LenSx laser with a 250-micron size grid pattern for a moderately dense brunescent cataract. The greater fragmentation and smaller cube sizes allow the lens to be chopped easily and the nucleus to be disassembled with less ultrasound energy. Source: Elizabeth Yeu, MD

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