EyeWorld Asia-Pacific September 2014 Issue

41 EWAP CAtArACt/IOL September 2014 Femtosecond - from page 39 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 femtosecond 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 incremental 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 research, Dr. Krueger said. For example, 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 gentle procedure 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 unplanned vitrectomy rate of 0.45% among 30,000 cases. In contrast, “During our first 820 refractive laser-assisted cataract cases with the Catalys laser [Abbott Medical Optics, Santa Ana, Calif., U.S.], we only had two unplanned anterior capsular tears, one of which led to a vitrectomy,” he said—“and the case that resulted in vitrectomy was an outlier” (a hypermature cataract). Depending upon whether or not one excludes the hypermature cataract, that results in a 0.12% or 0.24% unplanned vitrectomy rate and an anterior capsule tear rate that is likely lower than the very good results seen in the manual phaco population. Surgeons will also want more data going forward on complicated cases and laser use, Dr. Krueger said. This is still a speculative area because complicated cases are so much less common, he said. For example, fragmentation via phaco or a laser may not make a big difference in most cases, but differing results could lead to safer surgeries for challenging cataracts, such as cases with zonular dehiscence or subluxation. Dr. Talamo said he prefers to use the laser for complicated cases, such as dense cataracts and loose zonules. He noted that some of his uses with complicated patients are off-label. Future studies should and will examine differences in safety and efficacy among the different laser platforms, Dr. Culbertson thinks. “To lump them all together and generically treat the experience with an individual machine as representative of all the machines is inaccurate,” he said. Looking ahead The next evolution of femtosecond laser cataract surgery could include a greater degree of connectivity between the laser and diagnostic preplanning for improved refractive outcomes, Dr. Krueger thinks. He cited intraoperative aberrometry, available now from two companies, as one way to meet this goal. “We will put the intraoperative imaging to work for us to help calculate effective lens position, and we will design special IOLs that take advantage of the precise shaping, sizing, and position of the capsulotomy,” Dr. Culbertson said. Another up-and-coming area is Scheimpflug imaging to measure lens density. “If you could couple the information on how dense a lens is with the laser, you can have the laser treat more aggressively when it’s harder and less aggressively when it’s softer. That would make things more elegant,” Dr. Krueger said. The data on femtosecond lasers will show increased sophistication because the earlier models had certain limitations—and surgeons faced a learning curve, said William B. Trattler, MD , director of cornea, Center for Excellence in Eye Care, Miami, Fla., U.S. He cited, for example, how the hard dock of the LenSx (Alcon, Fort Worth, Texas, U.S.) evolved into the SoftFit Patient Interface, which improves the surgical process and makes surgery more comfortable for patients. “There is continuous improvement that will move this technology forward,” Dr. Trattler said. EWAP Editors’ note: Dr. Culbertson has financial interests with Abbott Medical Optics, Alcon, and other ophthalmic companies. Dr. Krueger has financial interests with Alcon, LENSAR (Orlando, Fla., U.S.), Calhoun Vision (Pasadena, Calif., U.S.), and other ophthalmic companies. Dr. Talamo has financial interests with Alcon, Allergan (Irvine, Calif., U.S.), Abbott Medical Optics, and other ophthalmic companies. Dr. Trattler has financial interests with LENSAR, Abbott Medical Optics, Allergan, and other ophthalmic companies. Dr. Vote has financial interests with Novartis (Basel, Switzerland). Contact information Culbertson: wculbertson@med.miami.edu Krueger: Krueger@ccf.org talamo: jtalamo@lasikofboston.com trattler: wtrattler@gmail.com Vote: eye.vote@me.com