EyeWorld India December 2014 Issue

64 EWAP NEWS & OPINION December 2014 Peristaltic pumps are traditional in phaco units. They separate vacuum and aspiration rate. However, the downside is they have a slow response time and require occlusion. “The lens material will not optimally come to the tip until occlusion is achieved,” he said. Meanwhile, with Venturi pumps the flow and vacuum are linked because the vacuum is always on and creates the flow. There is exquisite low vacuum low flow control, and the lens material comes to the phaco tip, Dr. Donnenfeld added. The downside with Venturi pumps is that because the vacuum creates the flow, there is danger of chamber instability if you create too high a vacuum. “Peristaltic is perfect when you have a large piece of nucleus and you want to bring it into the center of the eye,” Dr. Donnenfeld said. “This will grasp and hold more effectively because you’re using higher vacuum.” On the other hand, when you have small particles that will not occlude the tip, you want to use Venturi because it will allow phacoemulsification to occur even if you don’t have complete occlusion, he said. Presbyopia Solutions Remain ‘Uncut Stones’ Even after all these years of study and refinement, hearing them discussed and argued over by the greatest minds in ophthalmology at various scientific conferences around the world, options for presbyopia correction remain “uncut stones”—“they still have a lot of development to go,” Pannet Pangputhipong, MD , Bangkok, Thailand, said. Dr. Pangputhipong chaired a session titled “Perfect Presbyopia Solutions – Uncut Stones” in which world-renowned experts described the various options currently available for presbyopia correction. Kumar Doctor, MD , Mumbai, India, and Dr. Ang, Makati City, Philippines, each discussed a variation on the same concept: altering the shape of the cornea through the use of different ablation profiles, software or algorithms—PresbyMAX (Schwind, Kleinostheim, Germany) in Dr. Doctor’s case, SUPRACOR (B+L/ Technolas Perfect Vision, Munich, Germany) in Dr. Ang’s—in a presbyopic variation on LASIK. PresbyMAX creates a multifocal corneal ablation that works essentially as a bi-aspheric lens and must be applied binocularly to produce comfortable near and distance vision, Dr. Doctor said. Meanwhile, SUPRACOR, Dr. Ang said, uses a different algorithm to create a similar shape and effect—a cornea with an elevated center for near, with the periphery optimized for distance. Arguably the most popular presbyopia solution for cataract patients is multifocal IOLs. However, “We need to overcome the main problem of multifocal IOLs—image overlap and reduction in contrast sensitivity,” said Roberto Bellucci, MD , Verona, Italy. He described two “projects” directed at that very goal: the Bioanalogic IOL, a hydrophilic acrylic lens with no haptics and no apodization; and the Mini Well IOL, a hydrophilic acrylic, small incision, apodized IOL. The design goal of these two lenses is to treat a continuum of foci rather than discrete multiple foci. These lenses, he said, introduce a new concept of IOL with very good depth of field relying on different types of optics. Whether or not your cataract patients are presbyopic, Dr. Donnenfeld, Rockville Centre, NY, U.S., provided pearls for making unhappy premium IOL patients happy. He enumerated his “5 Cs”: (1) Cylinder and residual refractive error; (2) Cornea and ocular surface disease; (3) Cystoid macular edema; (4) Capsular opacification; (5) Center pupil on IOL. All cataract surgeons, he said, should address all issues that make patients unhappy through an intelligent step-wise approach keeping these 5 Cs in mind. Finally, Dr. Barrett, Perth, Australia, and Paul Rosen, MD , London, UK, discussed monovision. Monovision, said Dr. Rosen, is a key component in all forms of cataract and refractive surgery, and an important concept in all forms of presbyopia correction. Meanwhile, although most surgeons believe there is no single solution that works for every presbyopia patient, from a practical point of view, Dr. Barrett believes that, for as long as they are made aware of their options and properly educated on the various compromises, offering every patient his particular version of monovision—modest monovision, aiming for emmetropia in one eye and –1.25 D in the other, and using an extended depth of field IOL— will work very well. Pearls for IOL power prediction Saturday afternoon’s “Prediction Pearls: A Survival Guide” symposium offered attendees pearls for predicting refractive error in IOL power calculations and a useful guide for selecting the best power calculation formula in patients with challenging biometric issues. Dr. Barrett, Perth, Australia, and Dr. Hill, Mesa, Ariz., U.S., chaired the session, offering pearls and discussing the best course of action for several different power calculation scenarios. In addition, panelists Dr. Cionni, Salt Lake City, Utah, U.S.; Chan Wing Kwong, MD , Singapore; Dr. Malyugin, Moscow, Russia; and Dr. Bellucci, Verona, Italy, provided input and comments on power formula Jewels - from page 62