EyeWorld Asia-Pacific December 2016 Issue

December 2016 16 EWAP FEATURE Pearls for soft lenses by Ellen Stodola EyeWorld Senior Staff Writer Considerations for patients with soft lenses W hen it comes to handling patients with soft lenses, surgeons may need to consider specific techniques, machine settings, and other tools to help enhance surgical outcomes. Elizabeth Yeu, MD , Virginia Eye Consultants, Norfolk, Virginia; David R. Hardten, MD , Minnesota Eye Consultants, Minneapolis; and Deepinder K. Dhaliwal, MD , Lac, professor of ophthalmology and director of the cornea and refractive surgery services, UPMC Eye Center, Pittsburgh, commented on their preferred techniques and machine settings in these cases and shared pearls for avoiding complications. Preferred capsulorhexis size, technique, and viscoelastic In these cases, Dr. Yeu uses her routine capsulorhexis size and aims for one that is between 5.0 and 5.5 mm. “I try not to go too small as the density or gumminess AT A GLANCE • For patients with soft lenses, a standard capsulorhexis size of 5.0 to 5.5 mm can still be ideal. • Using a vacuum-based system can be particularly helpful to remove the nucleus, and minimal phaco power should be needed. • Surgeons should be aware of the “bowl” effect, which occurs when they are unable to effectively draw the entire piece of the nucleus out of the capsular bag. of the lens when I start the case will often dictate whether I use a chop or supracapsular technique for nuclear disassembly,” she said. For very soft lenses, such as pediatric or adolescent cataracts, Dr. Yeu prefers to prolapse the lens forward. “For a lens that has some sclerotic change to it but is a softer cataract, my go- to is either a horizontal chop with the Nagahara chopper or a reverse chop technique using the Koch spatula,” she said. For soft lenses, Dr. Yeu prefers a cohesive viscoelastic, like BD Visc (Beaver- Visitec International, Waltham, Massachusetts) or ProVisc (Alcon, Fort Worth, Texas). Dr. Dhaliwal also uses a standard capsulorhexis size of between 5.0 and 5.5 mm. Although physicians can use a standard capsulorhexis size, these cases can be challenging when not handled appropriately, she said. “The key for soft lenses are the hydro steps: hydrodissection and hydrodelineation.” If one can achieve good hydrodissection and hydrodelineation, the case should be very straightforward, she added. If not, the case may be a little more challenging because the surgeon won’t be able to chop or crack well. After Dr. Dhaliwal gets good hydrodissection and hydrodelineation, she makes a central groove and tries to split the lens if possible. Sometimes, it’s so soft that the instruments go right through it, she said. If this happens, Dr. Dhaliwal recommended using a second instrument to scoop the lens nucleus in toward the center. For viscoelastic, Dr. Dhaliwal prefers dispersive viscoelastic to coat the endothelium, and she specifically uses VISCOAT (Alcon). She added that right before doing hydrodissection and hydrodelineation, she decompresses the anterior chamber by depressing the wound and allowing viscoelastic to exit. “You want to get a nice cleavage between the capsule and cortex and allow the balanced salt solution to travel easily around the back of the lens and into a non-pressurized anterior chamber to avoid a posterior capsule ‘blowout,’” she added. Then, before putting the phaco tip in, replenish the viscoelastic just below the endothelium especially in patients with Fuchs’ dystrophy, she suggested. Dr. Hardten also finds that a 5.25 mm rhexis is ideal for all lenses, mainly because it provides a good overlap for the IOL optic. “While it is tempting to use a larger rhexis in patients with a soft lens so that you can more easily perform a supracapsular technique, it is the ideal lens centration that should define the rhexis size,” he said. In soft lenses, Dr. Hardten prefers a supracapsular technique. This is almost always possible in these soft lenses, he said. “By using initial hydrodissection and then keeping the cannula in the same location while you continue to slowly inject fluid, you can almost always prolapse the lens into the iris plane and anterior chamber without causing undue pressure on the capsule,” he said. “This avoids any tendency for peripheral epinuclear cataract that otherwise is hard to remove.” Dr. Hardten said that either a dispersive or cohesive viscoelastic is likely adequate for these cases, but he prefers to use a moderate weight dispersive to provide endothelial protection. Preferred machine settings Generally, soft lenses do not need much ultrasound energy for nuclear disassembly, Dr. Yeu said. The younger the patient, the more likely the lens can be slurped, without ultrasound or the phacoemulsification tip, only using I/A settings and handpiece. “Softer lenses tend to be sticky and gummy, and will not split very easily,” she said. “The two most useful settings for soft lenses are a chop setting that has a higher vacuum and burst/pulse mode and the I/A setting.” These lenses can be more safely removed by prolapsing anteriorly above the lens plane. Dr. Yeu said that trying to disassemble the nucleus can be frustrating, and can often result in bowling out of the lens, which can be quite challenging to remove. “The second instrument tends to be more active with softer lenses, particularly blunt or flat ones like a Koch spatula, and they can actively help scoop pieces out of the capsular bag as well as keep the posterior capsule back,” she said. Dr. Dhaliwal said that she uses a Venturi-based system. The vacuum-