EyeWorld India September 2017 Issue

September 2017 EWAP FEATURE 9 continued on page 10 the depressions has been some- thing that we’ve been surprised at how many abnormal corneas can benefit from this in both PRK and LASIK,” he said. Dr. Wiley treats all of his LASIK patients with topography-guided technology, provided he is able to obtain a good topography scan. However, he sees some physicians reserve the technology only for pa- tients with more irregular corneas. “Some people say, ‘Why use it if it’s a virgin eye with no prob- lems?’ Yes, chances are it may not make a big difference in those eyes where the topography effect is so small that you might only be treat- ing 1 to 2 microns of irregularity; however, there has been no demon- strated downside to treating even the slightest topographic irregulari- ties. … To me, it self-limits the eyes that are more regular,” Dr. Wiley said. On the other hand, he added that research has shown that some wavefront-guided technologies are not necessarily better for all cases. iDesign wavefront technology Edward Manche, MD , director of cornea and refractive surgery, Byers Eye Institute, and professor of ophthalmology, Stanford Univer- sity School of Medicine, Stanford, California, has used the iDesign aberrometer—which incorporates aberrometry, wavefront refraction, topography, keratometry, and pu- pillometry—for more than 5 years, participating in the FDA clinical trials that led to its approval. “I have had outstanding results with the iDesign wavefront-guided treatments,” Dr. Manche said. “A higher percentage of patients achieve visual acuities of 20/20 and 20/16 compared to the older WaveScan wavefront-guided treat- ments. The technology can also be used in an off-label fashion to treat highly aberrated eyes that were previously untreatable.” Similarly, Dr. Thompson men- tioned how this technology could benefit those with higher-order aberrations, as well as those with low light image quality issues. Dr. Manche went on to say that the current iDesign wavefront- guided technology has five times the resolution compared to the previous generation WaveScan system. “I have not found any dis- advantages to the new system and use it nearly exclusively for all of my wavefront-guided treatments,” he said. Dr. Wiley said that his practice has looked at iDesign but hasn’t brought on the technology yet. “It’s nice to see that the VISX plat- form [Johnson & Johnson Vision] is improving their technology,” he said. A 2016 study published in the Journal of Refractive Surgery com- pared visual outcomes of wave- front-guided ablation using the iDesign aberrometer and STAR S4 IR excimer laser system (Johnson & Johnson Vision) and topography- guided ablations with the EC-5000 CXII excimer laser system (Nidek). 1 Overall, the study authors con- cluded that both systems yielded “excellent results in predictability and visual function.” The wave- front-guided system showed some possible advantages in quality of vision, and selecting the appropri- ate system based on each patient’s eye conditions may be important, according to the study authors. SMILE As Dr. Slade put it, physicians are just starting to figure out who might be good SMILE candidates. In the U.S., SMILE is currently only approved to correct sphere, not astigmatism, limiting indications on that front. However, the data from the SMILE trial for astigma- tism has been submitted to the FDA for approval and “that data is excellent,” Dr. Slade said, noting that he expects approval will come within the next year and a half. Potential benefits to the SMILE procedure include biomechani- cal stability in the cornea, less inflammation, and fewer dry eye symptoms, though these have yet to be fully established, according to Moshirfar et al. 2 SMILE has been shown to result in less corneal denervation, fewer higher-order ab- errations, and faster corneal nerve healing compared to LASIK, the study authors wrote. What’s more, as a flapless procedure, it could be an option for those whose lifestyle or hobbies would carry the risk of flap trauma, Dr. Wiley said. “Some of the things that are more borderline—mild dryness or a slightly thinner cornea, a slightly higher prescription coupled with lifestyle—factor in to one proce- dure being a little better suited for a patient than another,” Dr. Wiley said. “At this point, it’s more of an art than a science, understand- ing the relative advantages versus disadvantages of these new proce- Dr. Wiley performs the femtosecond laser portion of SMILE with the VisuMax laser. This image shows the initial portion of the posterior “refractive cut”, which is the most posterior laser cut in SMILE. This is created in a circular pattern starting at the periphery and moving central.