EyeWorld is the official news magazine of the American Society of Cataract & Refractive Surgery.
Issue link: https://digital.eyeworld.org/i/220233
February 2011 November 2013 EW REFRACTIVE SURGERY 27 Refractive editor's corner of the world Focusing on LASIK femtosecond side cuts by Maxine Lipner EyeWorld Senior Contributing Writer E nhancement rates, while getting better, are still an integral factor in LASIK surgery. Most LASIK surgeons would agree that retreating a LASIK patient within the first six months is best done by simply lifting the previously created flap. The incidence of complications, including epithelial ingrowth, is low, the morbidity is low, and the success is quite high. But what about the patient who presents for a LASIK enhancement more than one year after LASIK eye surgery? What is the best way to enhance that patient— PRK over the previously created LASIK flap? Many LASIK surgeons would suggest that this is a safe and effective way to manage enhancements in patients when the surgery was one or more years later. Mitomycin is commonly used in these settings. PRK with mitomycin avoids the issues of flap complications and epithelial ingrowth. Still, there are surgeons and patients who prefer the convenience and speed of recovery that a LASIK enhancement affords. What is the best approach here? Should the flap be lifted, should a new LASIK flap be created? Can a new side cut be performed using the existing LASIK bed? Does it matter if the primary surgery was performed with a microkeratome or a femtosecond laser in terms of the approach to a LASIK enhancement? Sonia Yoo, MD, and colleagues address all of these issues. Thank you, Dr. Yoo, for your contribution, and to our readers, I hope you find this information helpful for your refractive practice. Kerry D. Solomon, MD, refractive editor Watch this video on your smartphone or iPad using your QR code reader. (Scanner available for free at your app store.) A: Configuration of a side cut made with the femtosecond laser (red line) within the old flap margin and extending beyond the level of the old interface posteriorly. B: Slit lamp photograph after femtosecond laser-assisted retreatment showing old flap margin (arrow) and new side cut within the flap margin (arrowhead). Studying implications for epithelial ingrowth W hen patients come in for LASIK retreatments, practitioners must decide the best way to approach these. Recent study results published in the August issue of the Journal of Cataract & Refractive Surgery showed that cases involving flap lifts were at a 5.7 times higher risk of developing epithelial ingrowth than those involving femtosecond side cuts, according to Sonia H. Yoo, MD, professor of ophthalmology, Bascom Palmer Eye Institute, Miller School of Medicine, University of Miami. While the need for retreatments has fortunately decreased in recent years, Dr. Yoo pointed out that there are some new issues here. "Although the general retreatment rate has gone down over time, we're now facing patients that are 5 or 10 years out from their original LASIK who come to us for retreatments," she said. "They present different challenges than someone who has had LASIK within the last three years." After this three-year period, the incidence of epithelial ingrowth goes up dramatically, she said. growth," Dr. Yoo said. "Also, it can be difficult to get in the edge of the old cut either because you can't see it or because it has been so long that it's healed into place." As a result, when the practitioner goes to lift the original flap it can be challenging, she said, and the edge can tear because it has been so long since the original surgery. However, cutting a whole new flap can be risky, Dr. Yoo said. "We have learned from our early days with microkeratomes that if you cut a new flap, one of the risks is that you can have a lamellar flap that's partially new, but then skips into the old interface and you could poten- tially create an irregular stromal bed," she said. The result could be bad visual effects. A side cut, on the other hand, can be a natural here. Because of the lack of blood vessels and cells in the interface, when you get to this area the flap tends to lift very easily, Dr. Yoo explained, adding, "It's the edge of the flap that can be difficult to lift." Eyeing ingrowth With this in mind, investigators launched the recent study to determine whether epithelial ingrowth incidence during myopic LASIK continued on page 29 Retreatment options "One of the reasons why we looked at making a new side cut was to try to decrease that rate of epithelial in- Slit lamp photograph showing epithelial ingrowth in an eye after retreatment with flap relifting Source (all): Journal of Cataract & Refractive Surgery