Eyeworld

EW CORNEA 28 December 2011 Considering whether FLAK improves corneal transplant outcomes A stigmatism outcomes for femtosecond laser-assisted keratoplasty (FLAK) are only significantly im- proved at the 4- to 6- month follow-up period compared to conventional penetrating kerato- plasty, according to Winston D. Chamberlain, M.D., assistant pro- fessor, Casey Eye Institute, Oregon professor of biomedical engineering, and director, Gavin Herbert Eye In- stitute, University of California, Irvine, agreed that technique came into play here. Dr. Steinert, who took part in the original study, thinks that even with femtosecond technology, the surgeon plays an important role. "There were major differences in the way that they did it," Dr. Steinert said. "The bottom line is no matter if you use a manual trephination or the laser, surgical technique matters in the approach; if you're really devoted to reducing the astigmatism, you can." He stressed that to do so practitioners need to monitor their outcomes and modify their techniques to drive re- sults in that direction. On the up side, investigators in Dr. Chamberlain's recent study demonstrated that with the FLAK technique they were able to remove sutures at an earlier time. "We think the designs that the femtosecond laser can cut are inducing faster healing and stronger graft host inter- face or corneal wounds that may allow us to remove sutures earlier," Dr. Chamberlain said. "That may allow for earlier visual recovery, and it also cuts down on risks associated with longer-term suture retainment in the cornea." Clinical possibilities From a clinical standpoint, Dr. Chamberlain sees the femtosecond technology as a major breakthrough in the keratoplasty surgery. "The laser certainly has applications to many types of corneal transplant techniques," he said. "The one that by Maxine Lipner Senior EyeWorld Contributing Editor Focusing on FLAK: Femtosecond technique compared to PK For Dr. Stein, while the concept is interesting, he said the question is whether it is right to do crosslinking when the incidence is about 1 in 3,000. "Surgeons certainly could make a case for crosslinking patients, whether they crosslink all patients or they crosslink patients who are at higher risk or patients with thinner corneas, slightly irregular topogra- phies, family history of keratoconus, and higher refractive corrections. We have not done this yet," he said. He wants to make sure from the data that there isn't an increase in complications from the laser por- tion. "For example, if there is a delay from putting the flap back down because surgeons have irrigated riboflavin under the flap and waited awhile and then irrigated again, is there a higher incidence of micro- striae?" While he hasn't heard of any re- ports that there is, it would certainly be concerning, he said. "We're wait- ing for published clinical studies be- fore getting involved with that." While clinicians wait for FDA approval, Dr. Donnenfeld said: "In the meantime, I don't think it's fair to our patients to allow them to de- velop progressive keratoconus and ectasia. Any patient who comes in to a clinician's office with progressive corneal thinning and ectasia should be directed to a doctor who is per- forming this treatment or sent abroad to another country where it's approved. We can't wait any longer and allow our patients to be need- lessly harmed by the lack of ap- proval of riboflavin UV crosslinking." EW Editors' note: Drs. Donnenfeld, Stein, and Stulting have no financial interests related to this article. Contact information Donnenfeld: 516-766-2519, eddoph@aol.com Stein: 416-960-2020, rstein@bochner.com Stulting: 770-255-3330, dstulting@ woolfsoneye.com Anxiously continued from page 26 Health & Science University, Port- land. Results published this past spring in Ophthalmology showed im- provement at just the one time point compared to several in an ear- lier study on this. The goal was to look at the first 50 patients who were done and compare them with 50 others who had very similar pathologies. "We wanted to try to analyze the out- comes to see if the femtosecond technique was actually improving our outcomes," Dr. Chamberlain said. A prior study published in the September 2009 issue of Ophthalmol- ogy had also looked at this but didn't have as many cases to consider. "They didn't have the power to analyze the results with similar pathologies in patients who received the conventional surgery," Dr. Chamberlain said. "I think this was one of the strengths of this study— we were able to do a much stronger comparison between conventional techniques and the femtosecond technique." Unexpected finding The first finding, which Dr. Chamberlain termed somewhat surprising, was that astigmatic out- comes in this study did not measure up to those in the original investiga- tion. "We only found a significantly different level of astigmatism in the femtosecond laser transplants at 6 months," Dr. Chamberlain said. By contrast, the original study found improvement in astigmatism results with the femtosecond laser at all early time points. A second finding indicated that there was no im- provement in best spectacle cor- rected acuity at any time point that was measured. Dr. Chamberlain thinks that the differences can be attributed to tech- nique variations. "The first study was done by one surgeon with one suture technique," he said. "We had three different surgeons with two different fellows involved using four different suture techniques." He thinks this introduced a variable, which needs to be assessed more. Roger F. Steinert, M.D., profes- sor and chair of ophthalmology,

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