EyeWorld Asia-Pacific December 2012 Issue

38 EWAP REFRACTIVE December 2012 Femtosecond - from page 37 and tighter interpalpebral fissures,” Dr. Waring said. “As a result, it should be a signal for companies to think about anatomic variations and custom tailor or at least offer different sizes for different anatomic variation.” Hazy outcomes Haze may be another issue with which femtosecond users may unexpectedly need to contend. Practitioners at Bascom Palmer Eye Institute in Miami recently found themselves in such a situation in a case involving a 42-year-old man who had undergone what seemed to be uncomplicated LASIK, according to Sonia H. Yoo, MD , associate professor of clinical ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Fla., USA. They reported on this case in the January issue of the Journal of Refractive Surgery. The haze wasn’t picked up initially but was noted some time later. “He wasn’t complaining of any light sensitivity or any post- operative problems in the early post-operative period,” Dr. Yoo said. “When he came back at 4 months, however, he did note blurred vision and had some recurrent refractive error, and that was at the same time that we noticed significant interface haze.” Investigators theorized that the haze was due to thin flaps. “When we measured the flaps they were calculated at much less than 100 microns,” Dr. Yoo said. “The right one was 73 microns and the left was 81 microns.” Using OCT, investigators found some very focal breaks in the basement membrane of the epithelium as well as Bowman’s layer that seemed to correspond with the areas of significant haze. “Our hypothesis was that if you make a very thin flap, potentially one of the causes of the haze is that you’re breaking through Bowman’s, and that’s what’s causing the haze,” Dr. Yoo said. “We assume that normally the epithelium is 50 microns but that there’s some variability between patients who may have a little thicker or thinner epithelium.” She thinks that if you start making a flap that’s thin in a patient who has a thicker epithelial layer than the average patient, you may start getting microscopic breakthrough of Bowman’s layer and even of the basement membrane that can cause haze. To avoid this, Dr. Yoo recommended limiting flap thickness to between 100 and 120 microns in most cases. “In my practice now my default flap thickness is 120 microns,” she said. “It’s rare that I go under 100 microns because I think there is some variability in epithelial thickness between patients.” In this particular case, the patient fared well. Because he had residual refractive error there was some question as to how to best re-treat this. “In this particular case you might consider using mitomycin-C to try and prevent the haze from recurring after the retreatment,” Dr. Yoo said. An alternative might be to do the retreatment as a surface ablation and remove the haze from the surface with the epithelium. Once again, Dr. Yoo recommended using mitomycin-C as an adjunctive agent to prevent haze recurrence. Overall, Dr. Yoo stressed caution in cases involving ultrathin flaps. “I would say to reserve ultrathin flaps for very specific cases because of the risk of haze,” she said. EWAP Editors’ note: The doctors mentioned have no financial interests related to this article. Contact information Waring: waringg@musc.edu Yoo: 305-326-6322, syoo@med.miami.edu