EyeWorld Asia-Pacific September 2016 Issue

September 2016 28 EWAP FEATURE SMILE are that the treatment is a flap-free procedure with minimal distortion of the corneal surface, and it does not induce spherical aberration possibly due to the physical removal of an intrastromal lenticule,” Dr. Hjortdal said. However, SMILE does have a slightly slower recovery of visual acuity on the first day after surgery. “With increasing refinement of laser settings, this difference is very small,” Dr. Hjortdal said. “After 1 week, most experienced surgeons Views from Asia-Pacific Sri Ganesh, MD Chairman, Nethradhama Hospitals Pvt. Ltd. 256/14, Kanakapura Main Road, 7th Block Jayanagar, Bangalore – 560070, India Tel. no. +91-80-2608-8000 Fax no. +91-80-2663-3770 chairman@nethradhama.org R eLEx SMILE is the new contender in the refractive arena and many surgeons are curious to know if it is as good as or better than the established LASIK and PRK techniques. A review of most of the published data on SMILE show that it is equal to or better than LASIK and PRK in terms of efficacy and safety. The many potential advantages that SMILE has are that it is a flapless procedure which eliminates all the risks of flap complications. Since the Bowman’s and anterior stroma are largely preserved, it may offer better corneal biomechanics in the long run. However, preoperative screening for ectasia should be as meticulous as for LASIK as it does not offer any additional protection in cases with abnormal topography. The incidence of dryness after SMILE is much less than with LASIK or PRK. The quality of night vision may be better due to reduced spherical aberration induction and effective larger optical zones. For the patient, SMILE offers a minimally invasive, short, painless, effective procedure with minimal postoperative restrictions which they find enthralling. The enhancement rates of SMILE are lower than with LASIK or PRK. However, SMILE is still in its development phase and is right now available only for myopic astigmatism. The Visumax laser which is the only femtosecond laser at present to offer the SMILE procedure does not have automated centration or cyclotorsion compensation. However, patient fixated centration and manual cyclotorsion are fairly effective. Hyperopic treatments are not commercially available, but initial trials indicate good results from mild to moderate hyperopia. Wavefront-guided and aberration corrective treatments are also not available as of now. Though the enhancement rate is very low, it has to be performed by converting the CAP into FLAP (circle software) or surface ablation. Few cases of repeat SMILE in small numbers have been done successfully but are off label. SMILE also has a steeper learning curve. With optimization of fluence, refinement of nomogram and technique, the first day visual recovery may be as good as LASIK. SMILE has been gaining popularity especially in the Southeast Asian market over the last 3–4 years with some surgeons having performed over 10,000 procedures individually. Globally, SMILE procedures continue to grow and have crossed half a million procedures to date. SMILE is an evolving procedure and most of the treatments available with LASIK and PRK will be possible in coming years. SMILE may just as well be the future of refractive surgery. Editors’ note: Dr. Sri Ganesh is a consultant for Zeiss and Abbott Medical Optics (Abbott Park, Illinois). SMILE - from page 27 do not find a difference.” Centration could be a possible issue in SMILE, Dr. Hjortdal said, but he noted that studies have shown a comparable increase in coma-like aberrations after SMILE and LASIK. “Complications related to lenticule removal are a potential concern in SMILE surgery, but this occurs very rarely,” he said. How SMILE compares to other procedures For correction of low myopia (less than 3 D) there are possibly no differences between the outcomes of modern surface ablation techniques, LASIK and SMILE, Dr. Hjortdal said, but prospective controlled studies are needed. “Concerning higher myopia (more than 6 D), we have found SMILE superior to LASIK in predictability and safety,” he said. “We do more than 95% of our surgeries for higher myopia as a SMILE procedure.” Dr. Ganesh recently worked on a study that will be published shortly comparing SMILE to PRK for low myopia. With PRK, there may be pain for a couple of days following surgery, and there is a need for long-term medication. Some patients may develop haze. “In our study, we found that the safety was better with SMILE,” he said. PRK is now widely being used for low myopia, Dr. Ganesh added. Though refractive results were similar between the two, he said that quality of vision in terms of aberrations was better with SMILE. Dr. Sekundo added that PRK is a great procedure but not for higher myopia; SMILE is preferable in these cases. When he counsels patients, Dr. Sekundo provides all of the options. However, for patients who have certain degrees of myopia, he won’t offer PRK or LASIK because he doesn’t think they are good choices. Future applications of SMILE Dr. Ganesh said that although SMILE cannot currently be used for hyperopia and enhancements, trials for hyperopia applications seem “quite promising.” It’s an evolving procedure that’s getting more refined, he said. At this point in time, LASIK is very refined, while SMILE is still in its infancy. “But even SMILE in its infancy is as good or better than advanced LASIK,” Dr. Ganesh said. “As it keeps developing, it’s going to get better.” Dr. Hjortdal said that the indications for the SMILE procedure could possibly expand to include hyperopic treatments and an optimization of astigmatic corrections. “Refractive corrections for presbyopia, such as ‘blended vision’ may also be possible,” he added. Dr. Sekundo is currently conducting the second phase of a study looking at SMILE in hyperopic patients, and he said different SMILE possibilities have been explored by Indian, Egyptian, and Singaporean colleagues. “SMILE requires a skilled surgeon,” he said. Dr. Sekundo added that he sees SMILE as better in the long term. Short-term results are usually equal to LASIK, but beyond 6 months, SMILE seems better. Initially, SMILE took around 2 minutes to perform, but currently, the procedure takes 24 seconds. Dr. Sekundo said he has not seen a single suction loss in the last 4 years, when the fast energy settings were implemented in his routine. In the future, he thinks the procedure will get down to around 10 seconds, with the high quality of cuts. It’s unfair to compare LASIK and SMILE, Dr. Sekundo said, because it’s comparing an old and well-proven technology—LASIK— to a new technology—SMILE. However, he noted that SMILE has been around for nearly a decade now and is continuing to evolve. EWAP Reference 1. Zhang Y, et al. Clinical outcomes of SMILE and FS-LASIK used to treat myopia: a metaanalysis. J Refract Surg. 2016;32:256–65. Editors’ note: Dr. Ganesh and Dr. Sekundo have financial interests with Carl Zeiss Meditec. Dr. Hjortdal has no financial interests related to his comments. Contact information Ganesh: chairman@nethradhama.org Hjortdal: jesper.hjortdal@clin.au.dk Sekundo: sekundo@med.uni-marburg.de