EyeWorld Asia-Pacific September 2015 Issue

44 EWAP REFRACTIVE September 2015 Preop scan of keratoconus patient Scan at 18 months postop of the same patient following UV crosslinking as well as bilateral topography-guided PRK Source (all): Ken Dickerson, OD Emerging technologies aim to expand refractive treatment by Rich Daly EyeWorld Contributing Writer Newer refractive treatments are showing promise A growing number of refractive options aim to expand treatment beyond what is currently possible with laser vision correction and without some of the side effects of the established technology. However, there are important limitations to consider with some of the new options, even when the newer technologies show great potential. Unanswered questions Small incision lenticule extraction (SMILE, Carl Zeiss Meditec, Jena, Germany) was developed as an alternative to traditional LASIK and PRK. The procedure involves passing a dissector through a small 2–3 mm incision to separate the lenticular interfaces and allow the lenticule to be removed, thus eliminating the need to create a flap. The international results and the unpublished preliminary U.S. clinical trial results are quite good, AT A GLANCE • International SMILE results are good, but the procedure comes with some tradeoffs. • Topography-guided refractive surgery may be limited to extreme cases. • Collagen crosslinking could expand indications for LASIK, but more research is needed. especially for low corrections with limited amounts of astigmatism, said Coleman Kraff, MD , director of refractive surgery, Kraff Eye Institute, Chicago. Potential benefits of SMILE are the relatively higher biomechanical strength of the remaining cornea and a reduction in the variability of the biomechanical effects produced by refractive tissue removal. However, there are some trade-offs involved with the SMILE procedure. For instance, surface ablation is required for enhancements, which eliminates one of its primary advantages. “Initially it may be touted as a less invasive procedure, but if patients end up with PRK retreatment, they’re not going to regard that as very successful in terms of meeting their expectations,” said Scott M. MacRae, MD , professor of ophthalmology and visual science, University of Rochester, Rochester, NY. “We need to be cautious about what type of expectations we create.” Dr. MacRae noted that some presented data has indicated that SMILE is more successful in patients with high myopia by leaving fewer higher order aberrations. However, the lack of peer-reviewed published data has left it unclear whether SMILE actually provides superior dry eye results compared to laser vision correction. Other unanswered questions include how to finish the case if suction is lost in the coupling suction applied to the peripheral cornea, Dr. Kraff said. He also emphasized the need to discuss the technology’s limitations with the patient ahead of time, due to its differences with traditional laser vision correction procedures. “There may be some patients who perceive that since there is no flap it is safer, but the jury is still out on that,” Dr. Kraff said. Therapeutic option The emerging technology of topography-guided refractive surgery is expected to find a place in the practice of Douglas D. Koch, MD , professor and the Allen, Mosbacher, and Law