Eyeworld

EW FEATURE 40 Keratorefractive surgery August 2015 AT A GLANCE • According to the PROWL studies, 98% of patients were satisfied or very satisfied with the procedure. • The iDesign relies on 1,250 data points, honing in on imperfections in the eye for LASIK. • Topography-guided LASIK offers precise primary outcomes and secondary therapeutic potential. by Maxine Lipner EyeWorld Senior Contributing Writer my cohort of patients and my out- comes were tremendous," he said. The quality of vision in the iDesign study was also outstanding, he said. Patient questionnaires showed de- creased halos and glare. "My general sense is that the quality of vision is improved with the iDesign because there are more data points and the way that the treatment profile is laid down on the cornea is more custom- ized, more accurate," he said. Another unique approach now in use is topography-guided LASIK. Arthur B. Cummings, MD, Wel- lington Eye Clinic, Dublin, Ireland, explained that the technique can be applied to regularize the cornea while correcting the refractive error. "Consider doing a wavefront-guid- ed procedure with an eye that has wavefront errors despite having a perfect cornea. After the procedure, the cornea will be irregular to com- pensate for the intraocular irregular- ities. With topography-guided, that's not the case—the cornea is always made more regular," Dr. Cummings said. This offers the potential to get better results with customized, primary treatments. In addition, the topography maps are repeatable. "You can take 10 topography maps and the 10 will almost look identi- cal," he said. The topography-guided ap- proach adds significant value to retreatment, he said. For patients who have a decentered ablation or a small optical zone, this approach works best, he stressed. With wave- front corrections, the only option practitioners have is to strive for emmetropia and attempt to remove all aberrations, Dr. Cummings explained. The topography-guided approach, however, offers flexibility patient selection and preop educa- tion are a key part of the process. "The PROWL studies by no means take away the importance and the duty of surgeons to carefully evalu- ate patients as surgical candidates," Dr. McDonnell said. "It doesn't guar- antee wonderful outcomes, but it can reassure us that for appropriate candidates, appropriately performed LASIK has a high margin of safety and a high degree of efficacy." Evolving approaches In addition to wavefront-guided and wavefront-optimized approaches, other modern LASIK approaches have emerged. In May the iDesign Advanced WaveScan Studio System (Abbott Medical Optics, Abbott Park, Ill.) received FDA approval. This system is used to capture informa- tion on any given patient and drives a customized treatment, according to Stephen C. Coleman, MD, in private practice at Coleman Vision Center, Albuquerque, N.M. The technology, which uses wavefront diagnostic aberrometry to pinpoint imperfections in the eye, relies on more data points than ever before. "There are currently 1,250 data points that are provided on the cornea as opposed to the WaveScan, which was about 250," he said. Dr. Coleman thinks this new technology offers better outcomes and decreased enhancement rates. "My feeling has always been that the single most important number in a practice is the enhancement rate," he said. "It's incumbent on the surgeon to keep that number very low for a variety of reasons." When he took part in the FDA trial for the iDesign, he had excellent results. "I have a zero enhancement rate for patients' reports of their ability to function under different circum- stances. The study included a military and a civilian population, with the military-based PROWL 1 consisting mostly of young, healthy males, and PROWL 2 more apt to include older civilians, Dr. McDonnell said. These populations were very different. "Young military recruits tend to have fewer issues like dry eye, which may be a particularly important con- sideration in refractive surgery, and the civilian population tended to be older, more female," he said, adding that older females in particular are more likely to have dry eyes, which can be problematic for refractive surgery. So examining these two dif- ferent populations was very helpful. Traditional results from this study at 6 months indicated that following LASIK, 99.5% of patients had 20/20 binocular acuity or better, with 76% attaining acuity of 20/12.5 or better. The study also included patient-reported outcomes, some- thing Dr. McDonnell views as very important. "The way we measure visual acuity on a high contrast acu- ity chart may be reproducible and consistent among offices, but pa- tients don't live in our exam lanes," he said. "They live out in the real world." If you want to truly know how successfully patients are func- tioning, why not ask them? That's what the instruments in the PROWL studies were designed to do. The results gleaned here were encouraging, he said. "While there are some people who report issues like glare and halos early on after surgery, if we look at how people do over time, issues like glare, halos, and ghost images 6 months after surgery were either at or below the level that patients had prior to surgery," Dr. McDonnell said. "At 6 months, 98% of patients said they were satisfied or very satisfied—only 2% were dissatisfied." Dr. McDonnell thinks this is reassuring. "Not everyone feels they have perfect outcomes, but the percentages are extremely high of people functioning very well." He sees the results as substanti- ating the idea that practitioners are providing patients with outstanding LASIK outcomes. Still, the smart ophthalmologist understands that Modern LASIK by the numbers Quantifying patient perspectives and beyond J ust how effective is modern LASIK with current state- of-the-art technology? EyeWorld is drilling down on study results that take patients' perspectives into account, as well as more traditional data. The recent PROWL 1 (Patient- Reported Outcomes With LASIK) and PROWL 2 studies assessed patient satisfaction with wavefront- guided and wavefront-optimized ablations and put numeric perspec- tive on this. The idea behind this 2-pronged study was to shine a light on the impact that the surgery has on patients, according to Peter J. McDonnell, MD, William Holland Wilmer professor and director, Wilmer Eye Institute, Johns Hopkins University, Baltimore. Some resistance to refractive surgery goes back to the old days of radial keratotomy. "There have been people who are tremendous adherents, who have had surgery and feel that it is very positive and even transformative for them," he said. "There has also been a vocal minority of people, however, who feel there have been problems." When PRK came along, such issues diminished, but with LASIK these concerns resurfaced in some corners. Patients' perspective "In an effort to generate more light and less heat and to have actual data, efforts have been underway to try to measure more accurately the impact of refractive surgery on patients' lives," Dr. McDonnell said, adding that the PROWL study included not only easy-to-measure factors such as visual acuity but also " Not everyone feels they have perfect outcomes, but the percentages are extremely high of people functioning very well. " –Peter J. McDonnell, MD

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