EyeWorld Asia-Pacific March 2011 Issue

11 EW FEATURE March 2011 Lens fragmentation in process; in this case, pie-like cuts are used to fragment the cataract Rhexis after laser procedure Setup of the LensAR System Source: William J. Fishkind, MD The Optimedica Catalys Precision Laser System Source: Optimedica Femto technology changing the cataract landscape by Maxine Lipner Senior EyeWorld Contributing Editor Laser systems offer new approach for cataract removal F or years there has been essentially one modern way to do cataract surgery— phacoemulsification. In its day this was heralded as a huge step forward over extracapsular surgery. Now, however, a new 21st century method, which hinges on a high- tech, femtosecond component, is emerging. Currently there are four key players in the arena—the LenSx system (Alcon, Fort Worth, Texas, USA/Hünenberg, Switzerland), the LensAR system (Winter Park, Fla., USA), the Optimedica Catalys precision laser system (Santa Clara, Calif., USA), and the Technolas Workstation 520F (Munich, Germany). We took a closer look at each of these and what they had to offer. So far, the system that has made the most inroads in the United States is the LenSx with current 510K clearance for use in patients undergoing cataract surgery for removal of the crystalline lens. The LenSx system, recently acquired by Alcon, has clearance for four indications, according to Stuart C. Raetzman, area president of the United States, and vice president of global marketing, Alcon. Intended uses in cataract surgery include anterior capsulotomy, phacofragmentation, and the creation of single-plane and multi- plane arc cuts or incisions in the cornea. He points out that none of the other systems have been approved for all of these indications. Early investigational work Early international work with the LenSx system was done by Zoltan Nagy, MD, clinical professor of ophthalmology, Semmelweis University, Budapest, Hungary. In the United States, Stephen G. Slade, MD, director, Laser Center of Houston, Houston, and medical director, LenSx, has been the surgeon who has been shepherding the LenSx procedure through early Food and Drug Administration (FDA) rigors and performing early clinical work. “The second laser that was placed was here in Houston, and we’ve been doing cases after it was approved through the FDA, in February 2010,” he said. Dr. Slade has also participated in clinical studies considering safety and effectiveness. “We’ve looked at phaco times both here and in Budapest and we’ve found that we’ve reduced these [by] 40–50%,” Dr. Slade said. Investigators also found that endothelial cell count loss was lower when the LenSx system was used. “If you use less energy you should lose fewer cells,” Dr. Slade said. Also, he points out that with the femtosecond approach less maneuvering is needed, which could further preserve cells counts. Investigators also considered whether patients could see better uncorrected after cataract surgery. In work done by Dr. Nagy comparing femtocapsulotomy to manual capsulotomies, the femtosecond approach was found to be superior. “It turns out that we can make a much more precise capsulotomy,” Dr. Slade said. “The size and centration and regularity of the capsule do make a difference in the contraction of the capsule and how much variability you get in the sphere power of the lens.” They also looked at astigmatism induction and correction with the system. “We have shown that we can much more precisely control the incisions,” Dr. Slade said. “We can also treat preexisting astigmatism with astigmatic keratotomies.” LenSx essentials The LenSx system boasts two key components. “It’s a femtosecond laser with integrated optical coherence tomography (OCT),” Mr. Raetzman said. “The OCT is designed to provide the physiological landmarks that a surgeon can use to precisely plan many of the manual steps in a cataract procedure.” Mr. Raetzman sees the femtosecond cataract procedure as a remarkably precise one, which still allows for considerable surgeon input. “Just like a LASIK [femtosecond] procedure there’s a patient interface, so, the laser and the eye will be connected and then the OCT will take very precise measurements of the lens and the anterior chamber and the cornea,” Mr. Raetzman said. “Then it allows the surgeon to direct the laser to where the cuts need to be made.” The same is true for the capsulorhexis as well. For nuclear disassembly the surgeon tells the laser how many pieces to cut the nucleus into. “It takes the manual Surgical View System Video View steps, all of those steps that are kind of high-stress for the surgeons, like the capsulorhexis and it provides a level of confidence that you’re going to be able to do that predictably and reproducibly every time but that the surgeon is still in control,” Mr. Raetzman said. Dr. Slade finds that femtosecond approach ultimately simplifies the phacoemulsification procedure. To begin with the laser docks to the patient and then the practitioner gathers an image with the OCT. Then guided by that image the surgeon can design the procedure. “You design the capsulotomy, you design your incisions and the nuclear cracking and then any astigmatic incisions,” Dr. Slade said. The laser starts posteriorly, comes up through the nucleus, makes the capsulotomy, makes the cataract incisions, and makes any astigmatic incisions. Only after this is complete is the patient rolled into the operating room. “Cataract surgery has about five steps: the incisions, the capsulotomy, the nuclear cracking and removal, the cortex removal and then the implantation of the IOL,” Dr. Slade said. “This laser does about two and a half of those five steps.” Anterior capsulotomy after completion of laser procedure Source: Frieder Loesl, PhD; CustomLens by Technolas continued on page 12