EyeWorld Asia-Pacific March 2016 Issue

53 EWAP REFRACTIVE March 2016 SMILE vs. LASIK in terms of corneal sensitivity Source: Dan Reinstein, MD Beyond pure wavefront by Maxine Lipner EyeWorld Senior Contributing Writer Matching the ablation profile to the patient P atients who come in for refractive surgery today are more exacting than ever before. As a result, attaining great outcomes may mean straying from traditional wavefront LASIK, with practitioners concentrating on maximizing visual quality rather than solely attempting to hit the 20/20 mark, according to Sonia Yoo , MD , Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami. “I think now that refractive surgery is in a more advanced time in its evolution, our goals are not only to get patients to 20/20 vision but also to get them to the best quality of vision that we can,” Dr. Yoo said, adding that’s why practitioners may wish to customize ablation patterns based on their patients’ aberration patterns and not just their preoperative refractive error. This may mean considering cutting-edge procedures such as topography- guided approaches or the small incision lenticule extraction (SMILE) technique. Topography-guided inroads Topography-guided procedures have strong therapeutic roots, but there can be occasions where patients may benefit from the approach rather than a wavefront ablation. Dr. Yoo cited those who have slightly asymmetric corneal topography. “Those patients can get better quality of vision with topography-guided treatments,” she said. Edward E. Manche, MD, professor of ophthalmology, Stanford University School of Medicine, and director of cornea and refractive surgery, Stanford Eye Laser Center, Stanford, Calif., agreed that using the right type of ablation profile is of paramount importance. One set of patients that may be well suited for topography-guided treatment rather than wavefront is those with large angle kappa, he noted. In a case where the patient has this and the practitioner wants to center over the line of sight instead of over the entrance pupil, the ability to have a topography- guided procedure could have some advantage. Still, he stressed that this is controversial. “Some people are in the camp that all surgery should be centered on the entrance pupil—that’s how most lasers are set up,” he said. “There are others who say that in cases of hyperopic LASIK, you should center not necessarily over the entrance pupil but the line of sight that is approximated by the first Purkinje reflex.” The thinking is this could minimize visual issues like halos, Dr. Manche explained. He views the topographic approach as having wider potential than strictly therapeutic applications, pointing out that in November 2013, the WaveLight Allegretto Wave Eye-Q system (Alcon, Fort Worth, Texas) was recommended for FDA approval in primary cases. Results in the FDA clinical trial indicated that at the 3-month mark, 99.2% of patients had 20/40 or better acuity, 92% saw 20/20 or better, and 68.9 saw 20/16 or better, Dr. Manche said, adding that the results were comparable to those seen with the wavefront- optimized and wavefront-guided approaches. “It appears to have similar efficacy in virgin eyes.” Still, looking internationally, very few people are using topography-guided treatment as a primary treatment, Dr. Manche noted. He doesn’t think investing in the topography-guided approach would make sense for the casual user. When it comes to primary cases, this has not made inroads in larger practices either, Dr. Manche pointed out. “I spoke with someone who is the medical monitor of a group of laser centers in Europe, and out of 100,000 treatments a year, maybe 12 patients need to have topography-guided retreatments to address an issue after their primary LASIK surgery,” he said. Dr. Yoo sees the topography- guided approach as having considerable value from a therapeutic standpoint. “I have a specialty practice; it’s a referral practice and I see a lot of complicated cases,” she said. “One of the things that makes patients apprehensive about having refractive surgery is the notion of what will happen if something goes wrong.” Knowing that if this happens there is recourse would likely make patients less apprehensive about having surgery, Dr. Yoo thinks. “It certainly would be beneficial to have that available so if you were faced with an outcome that was less than ideal, you would have the tools to fix it,” she said. continue on page 54