Innovations | Apr 2012

The Good, the Bad, and the Ugly—ie, the LASIK Flap

Over the years, many impressive innovations have revolutionized refractive surgery. One of the many genius surgeons who helped to transform this field was José Barraquer, who, in his clinic in Bogota, Columbia, developed the first microkeratome. He used the microkeratome to cut thin flaps in the cornea and alter its shape, in a procedure he called keratomileusis.

One of the first commonly used microkeratomes was the Automated Corneal Shaper from Chiron. At this early stage of refractive surgery, however, complications such as epithelial abrasions, buttonholes, incomplete or torn flaps, and free flaps became nightmares for surgeons all over the world. Due to these procedural difficulties, flaps got a bad reputation. In fact, many surgeons in certain countries, such as the United States and the Netherlands, abandoned LASIK and ultimately opted for surface ablation as the safer procedure. Unfortunately, surface ablation also had its share of problems, as it is difficult to control the associated pain and prolonged healing process.

I also worried about the flap complications of LASIK in those early days and, in 2003, I became a proponent for epi-LASIK. This technique was developed by Ioannis G. Pallikaris, MD, PhD, of Crete, Greece. In short, epi-LASIK is basically automatic LASEK without alcohol. One of the advantages of this technique is that the stromal bed is smoother than that obtained by mechanical methods or by brush; however, pain was still significantly worse than with LASIK. Additionally, haze formation could not be ruled out completely after an epi- LASIK procedure.

During more recent years, mechanical microkeratomes such as the Hansatome and the Zyoptix XP (both by Bausch + Lomb), the Carriazo-Pendular (Schwind eyetech- solutions), and the One-Use Plus and M2 single-use microkeratomes (both by Moria) helped to minimize these complications and became the standard of care. As these advances optimized LASIK results, many surgeons shifted their preferences back to LASIK.

One of the major advantages of LASIK is the ease with which a retreatment can be performed. Even many years after the initial surgery, lifting of a flap is still possible. In these cases, it is important to inform the patient that there is a higher risk of epithelial ingrowth as a possible side effect.

Today, the current trend in LASIK is the creation of a thin flap. Flaps of approximately 100 to 120 μm help to preserve the biomechanical stability of the cornea and reduce the risk for postoperative dry eye. With current femtosecond laser technologies—another revolution in refractive surgery—a stromal lamellar cut as thin as 80 μm is now possible. With this technique, not only dry eye but keratectasia as well may be minimized.

For the past several years, femtosecond lasers have been replacing mechanical microkeratomes as the gold standard for corneal flap creation all over the world. Although the cost is significantly higher, patients and surgeons are embracing this appealing technology. Platforms such as the LDV CrystaLine (Ziemer), Victus (Bausch + Lomb/Technolas Perfect Vision), VisuMax (Carl Zeiss Meditec), IntraLase (Abbott Medical Optics Inc.) and FS-200 (Alcon Laboratories, Inc.) all are capable of making high quality flaps in the cornea.

Contributors to this issue highlight the advantages of all-laser LASIK, but they also provide an overview of the LASIK flap, from its ideal size and construction, to dealing with complications, and to acknowledging when to abandon the procedure. The list of authors in this month’s issue is impressive, and the articles cover not only historic perspectives and future developments of the LASIK flap but also debate the pros and cons of this surgery. It is obvious that LASIK is here to stay for many years to come.

Finally, I would like to thank the editorial staff and all colleagues for their continued efforts to make CRST Europe the most up-to-date publication in the world of cataract and refractive surgery.