EyeWorld Asia-Pacific June 2012 Issue

June 2012 17 EWAP FEATURE Patrick VERSACE, MD Vision Eye Institute 2/75 Grafton St., Bondi Junction 2022, Australia Tel. no. +61-2-93863666 patrickv@vgaustralia.com T here was a dark time about 15 years ago when epithelial ingrowth was high on the list of possible problems after LASIK. Early microkeratomes were not great at creating a predictable flap architecture that included an edge profile that would act as a barrier to the ingress of proliferating epithelium. Happily, the femtosecond laser changed all that and we are now able to create an excellent flap edge profiles that really seal the opening against all but the most voracious epithelium. There are exceptions and femtoseconds that have no Z scanning (such as Ziemer) fail in this area. The higher incidence of ingrowth in hyperopic (as compared with myopic) ablations (Parker; Cornea 2011) may be due to flap architecture as the corneal surface area is increased in hyperopic ablations and the flap is less able to cover the gutter region. Unfortunately, we are still faced with the more frequent problem of epithelial ingrowth with flap lift enhancements. As the authors agree the best solution is to avoid the problem and do surface laser treatment enhancement but this is not always preferable for the patient. Certainly for the older age group discussed (post IOL enhancement) surface treatment is my preferred option and works well for the typically small corrections performed. The use of bandage contact lenses after flap lift enhancement is a commonly used intervention despite a confusing paper that suggested the contact lens may increase the incidence of ingrowth (Chan CC, Boxer Wachler BS. Comparison of the effects of LASIK retreatment techniques on epithelial ingrowth rates. Ophthalmology 2007;114:640-642). It would be easy to form the view from the discussion around management that ingrowth is often difficult to treat but in reality it is uncommon to need more than flap lift and clean out. A newer intervention that may make this a lot less stressful is the use of OcuSeal liquid Ocular Bandage (HyperBranch Medical Technology, Dunham, NC, USA)—the liquid sealant is painted on to the flap edge to close the gap and prevent epithelial ingress. No-flap LASIK may be better still; perhaps the near future will see the early adoption of lenticule extraction techniques as popularized by Zeiss with the Visumax femtosecond laser. Editors’ note: Dr. Versace has no financial interests related to his comments. Views from Asia-Pacific at that one spot one clock hour and open up the flap edge. He recommended tugging the edge of the flap a bit toward the center to demarcate this. Then he suggested using forceps to grasp the exposed edge and lift and peel it back to create a very smooth, perfectly torn edge. Many times it is possible to then go on to the enhancement. Other times there may be a little resistance. “If you feel you don’t want to tug on it any more after you get about halfway back, you can use a tri-cellulose sponge and just by pressing on the flap you could press it back all of the way,” he said. “After the laser ablation you take the cellulose sponge and go all the way around the edge of the flap and make sure that you haven’t left any epithelial tags over the edge of the stroma.” With this technique Dr. Wilson finds epithelial ingrowth is virtually unheard of. Innovative treatment options Of course, even with the best techniques practitioners may still find themselves battling an ingrowth case. Dr. Desai has found that one good way to combat this is to use ethanol on a Weck-Cel spear. He scrapes the back of the flap and the bed and uses the spear to devitalize any remaining epithelial cells. He also urged considering 10-0 nylon suture use to make sure the flap remains down for those who feel that they can do so without creating stria. Jorge L. Alio, MD , professor and chairman of ophthalmology, Miguel Hernandez University, Alicante, Spain, and medical director, Vissum Corporation, Alicante, has pioneered the use of the YAG laser in epithelial ingrowth cases. With the technique, practitioners position the patient under the YAG laser and choose the smallest spot possible using minimal energy to begin. This is increased until a visible bubble is seen at the interface. Dr. Alio finds that 1.5 millijoules of energy is usually sufficient here. “Once you have a bubble and the bubble is at the level of the epithelial ingrowth, then you start doing the same in the surrounding areas,” he said. “These bubbles have to be one by the other, not overlapping.” In addition to the bubble itself, the shockwave destroys epithelial cells, allowing practitioners to keep the needed number to a minimum. “I always start with the fistula, defining this as the place you know that most epithelial cells have been percolating inside the interface,” Dr. Alio said. He stressed, however, that there are two different types of epithelial ingrowth—one composed solely of cells and the other of cells and mucin. Cases involving mucin are the one indication he sees for flap lifting. Otherwise, Dr. Alio has been very successful with the technique, which he stressed can be repeated if needed. Overall, Dr. Desai worries that with older patients becoming more interested in refractive options for cataract surgery and the like, if practitioners aren’t careful, ingrowth rates will climb. “We’re going to see a rise in rates of epithelial ingrowth if we’re not careful to screen the patients, adjust our treatment planning, adjust our intraoperative technique, or guide the patient to a different option,” he said. EWAP Editors’ note: Dr. Alio has no financial interests related to this article. Dr. Desai has financial interests with Alcon (Fort Worth, Texas, USA/ Hünenberg, Switzerland) and Bio- Tissue (Miami, Fla., USA). Dr. Packer has financial interests with AMO and Bausch + Lomb (Rochester, NY, USA). Dr. Wilson has no financial interests related to this article. Contact information Alio: +34-670-33-33-44, jlalio@vissum.com Desai: +1-727-518-2020, desaivision@hotmail.com Packer: +1-541-687-2110, mpacker@finemd.com Wilson: +1-216-444-5887, wilsons4@ccf.org Epithelial ingrowth Source: Patrick Versace, MD