Eyeworld

EW FEATURE 28 by Vanessa Caceres EyeWorld Contributing Editor Evaluating the femtosecond laser for cataract surgery Accuracy and safety touted—surgical outcome improvements still under review "T he femtosecond laser is a very excit- ing technology, and I think it's rea- sonable to be en- thusiastic about this technology," said Stephen S. Lane, M.D., clinical professor of ophthalmology, Univer- sity of Minnesota, Minneapolis. "However, it's also in its early stages, and there are a lot of questions to be answered … There's a lot of sizzle right now with this, but not a lot of substance. We need to get to the point where there's more substance than sizzle." "We're looking at early genera- tion equipment, which is interest- ing because we as surgeons tend to be inventive and if you give us a tool, we'll find new ways to use it," said William J. Fishkind, M.D., clinical professor of ophthalmology, University of Utah, Salt Lake City, and clinical instructor of ophthal- mology, University of Arizona, Tuc- son. "I think the femtosecond laser for cataract surgery is a fertile area for this kind of thinking. As we use it more, we'll better understand how to use it and find new ways to use it." The pool of users for these lasers is still small as only two models cur- rently have U.S. FDA approval. The LenSx Laser (Alcon, Fort Worth, Texas) is available now in the United States for anterior capsulotomy and lens fragmentation. The LensAR Laser System (Winter Park, Fla.) was approved by the FDA in March for anterior capsulotomy and lens frag- mentation. The OptiMedica Catalys (Santa Clara, Calif.) and the Technolas Customlens (St. Louis) are not yet available in the United States. EyeWorld interviewed users of this technology to find out individ- ual strengths, weaknesses, and slated improvements. LensAR Laser System Dr. Fishkind performed 14 cases with the LensAR model in Mexico City approximately a year ago and anticipates getting his own unit in the third or fourth quarter of this year. For him, the biggest strength is how it can potentially more easily remove chunks of lens material than a chopping procedure. "Can you quantify how much easier? No, but it was clearly efficient. In softer cataracts, it allowed aspiration with- out phaco energy. With grades 3, 4, and 5, phaco energy was necessary, but the cataractous pieces were more easily mobilized, and emulsification was very well controlled," he said. "Where I see this being helpful as a cataract surgeon is that you won't have to use as much phaco energy to remove a cataract, and you can potentially do it more safely," Dr. Fishkind said. "There's not as much manipulation, and there's less power necessary for the emulsifica- tion process." He cited his own data, which found that when using pie- shaped algorithms, the cumulative dissipated energy was reduced by 64% in grade 2 cataracts, 40.5% in grade 3 cataracts, and 41.6% in grade 4 cataracts. "In grade 1, we didn't use power at all, they were just aspirated" (Figure 1). Dr. Fishkind also sees advan- tages with this technology when performing capsulorhexis, as the capsulorhexis could be created to any desired size, and would be sym- metrical and perfectly round. "You should be able to center the capsu- lorhexis over the visual axis, and then center the implant in the cap- sulotomy and therefore in the visual axis," he said (Figure 2). LensAR has an imaging system —3D-CSI, or Confocal Structured Illumination—to help users con- struct a 3D image of the cornea, iris, and anterior and posterior capsules with micron-level sensitivity, Dr. Fishkind said. This kind of imaging can particularly help with treating grade 4 and 5 cataracts as well as brown cataracts because of the capa- bility to image these dense cataracts, he said (Figure 3). Like other femtosecond cataract lasers, the LensAR unit can help sur- geons perform the incision, paracen- tesis, and limbal relaxing incisions with greater accuracy, Dr. Fishkind said. Use of these lasers may require some innovative logistical thinking in terms of where to perform the laser-based portion of the procedure and where to perform the remaining surgery, he said. Dr. Fishkind hopes that Medicare will eventually update its payment model to allow patients to pay extra for premium technology such as laser use. This would affect not only ophthalmic devices but also hip and knee joints, pacemak- ers, and other devices, he said. Alcon's LenSx Laser As of late May, Eric D. Donnenfeld, M.D., clinical professor of ophthal- mology, New York University, along with other surgeons at his practice, had performed 150 laser cataract sur- geries with the LenSx model over a 6-week period. The laser is used in patients with pre-existing astigma- tism or in those who request a pre- mium IOL. "The procedure has significantly raised the bar with accuracy and pre- cision while reducing the energy re- quired, making it, in my opinion, safer and more effective with better outcomes," Dr. Donnenfeld said. The arcuate incisions that are created have a uniform depth and length, leading to more regular to- pography, he said. In the future, Dr. Donnenfeld hopes to change the ar- cuate pattern to make it even more adjustable. According to Dr. Donenfeld, an- other advantage of the laser is that all capsulorhexes performed have been precisely created to the desired diameter and centered in the desired location. Once the lens is chopped into four quadrants, a chopper or an- other device still needs to be used to divide and remove the lens, Dr. Donnenfeld said. To better facilitate surgery, a pa- tient needs to be moderately compli- ant and able to lie still so as not to knock off the suction plate, Dr. Donnenfeld said. He expects the laser software to have better lens disruption programs in the future. He also would like to see future changes to the incisions for reverse side cuts. February 2011 Laser-assisted cataract surgery July 2011 Figure 1. Laser fragmentation algorithms Source: William J. Fishkind, M.D. AT A GLANCE • Surgeons who have used femtosec- ond lasers in cataract surgery believe the laser helps create a more reproducible procedure • At this time, only two femtosecond lasers created for cataract surgery are approved for use by the U.S. FDA • Improvements can be made to the lasers, which are still in the early generation of technology • Surgeons would like to see a sus- tainable economic and logistical model to purchase and use these lasers

• Cover