Eyeworld

EW FEATURE 32 by Vanessa Caceres EyeWorld Contributing Writer Femtosecond laser advantages for cataract surgery evolving Ever-changing technology requires continuous study I dentifying the clinical advan- tages of femtosecond laser refractive cataract surgery is like shooting at a moving tar- get, as research studies in this hot area of cataract surgery continue to emerge. A PubMed search of the term "femtosecond laser cataract surgery" yielded 287 results in mid May. Surgeons speaking at the 2014 ASCRS•ASOA Symposium & Congress in Boston touted what the research shows but also where it still lacks. "It depends on what outcomes you're tracking," said William W. Culbertson, MD, professor of oph- thalmology, director of the cornea and refractive surgery services, and the Lou Higgins chair of ophthal- mology, Bascom Palmer Eye Insti- tute, Miami. "If you look at visual acuity outcomes or safety outcomes, the results of laser cataract surgery compared to manual phaco are simi- lar, largely because the results and safety of routine surgery are so good anyway. However, most surgeons who have used the lasers and who have done enough cases to make it through the learning curve for the laser are convinced that it makes the surgery easier and more precise." Refractive outcomes Some refractive advantages with the use of the laser have emerged in the existing studies, surgeons said. "What we do know is that refractive laser-assisted cataract surgery causes less endothelial cell loss, better IOL centration, and less decentration over time," said Jonathan H. Talamo, MD, associate clinical professor of ophthalmology, Harvard University, Boston. "All the markers that we look for such as lower phaco energy, less endothelial cell loss, precision of capsulotomy diameter, shape, posi- tion, and precision of the relaxing incision depth, and arc length have been well-documented in the litera- ture," Dr. Culbertson said. "To say that the laser does not help would be to say that these important pa- rameters don't matter and would fly against many of the basic assump- tions that we've made over 40 years using phaco small-incision cataract surgery." Ronald Krueger, MD, Depart- ment of Ophthalmology, Cleveland Clinic, Cleveland, said that astig- matic incisions created with the femtosecond laser are shown to offer an advantage because they are more controlled and performed with laser precision. "It makes sense that they would be better than a blade. In terms of depth and length of the in- cision, they can be more titratable," he said. That's in contrast to the primary incision, which can likely be cut to the same size with either a keratome or a laser, Dr. Krueger said. "I know surgeons who use the blade because it doesn't make much difference," he said. Another area with emerging evi- dence is the laser's ability to create a capsulorhexis that is perfectly cen- tered and sized to allow for better prediction of effective lens position, Dr. Krueger said. The data in this area are not yet conclusive, he said. However, in a presentation at the 2014 ASCRS•ASOA Symposium & Congress, Brendan Vote, FRANZCO, Launceston, Australia, cautioned that femtosecond laser refractive cataract surgery still needs randomized control trial data and long-term prospective comparative cohort data (rather than case series compared with historical data). "From the current evidence, I do not think we can yet say that femtosec- ond technology is safer than phaco. Similarly, I do not think we can yet say that femtosecond is better than phaco," he said. "The plusses may outweigh the minuses, but there remain significant safety signals such as capsulotomy integrity, cystoid macula edema, and posterior capsule opacity. Furthermore, corneal benefits of reduced, effective phaco time were lost by 6 months postoperatively with no difference. My impression is that early femto technology may offer some incre- mental benefits over phaco, but these are not cost effective at the current cost to patients." Areas to consider Some portions of femtosecond laser cataract surgery require further re- search, Dr. Krueger said. For exam- ple, lens fragmentation with a phaco instrument or a laser will not change refractive error or precision in most cases. "The only potential benefit is with more complicated cases, where maybe by doing a more gentler pro- cedure with pretreatment, you can avoid a more complicated outcome. That may affect the refractive results," Dr. Krueger said. Safety is another area where data will continue to emerge. For instance, there have been conflicting reports regarding anterior capsule tear rates. "The safety issues with that are equivocal and may have to do with the laser platform," Dr. Krueger said. From experience at his clinic in a phaco-only population, Dr. Talamo reported a low anterior capsule tear rate based on an un- planned vitrectomy rate of 0.45% Refractive results of femtosecond laser cataract surgery June 2014 AT A GLANCE • Emerging evidence indicates that femtosecond laser refractive cataract surgery has some refractive advantages over phacoemulsification, including the creation of astigmatic incisions and less endothelial cell loss. • Femtosecond laser refractive cataract surgery needs long-term, randomized trial data and studies to demonstrate benefit over traditional phaco. • Studies still need to conclusively show the advantage of lasers in complicated cataract cases. Anecdotally, surgeons will use the laser in these patients, but the small number of complicated cases makes it a difficult area to formally study. • Lasers will continue to improve, leading to refined outcomes. Comparative precision of a manual blade vs. laser incision. Depth, orientation, and length are more predictable and titratable with a laser, and will give a greater and more accurate effect than a manual blade, some surgeons believe. Source: Eyemaginations 32-41 Feature_EW June 2014-DL_Layout 1 6/3/14 12:31 PM Page 32

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