Eyeworld Supplements

EWAP FALL 2017 - Sponsored by Carl Zeiss Meditec

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The news magazine of the Asia-Pacific Association of Cataract & Refractive Surgeons Sponsored by Carl Zeiss Meditec SMILE: Redefining refractive surgery APACRS Supplement to EyeWorld Asia-Pacific Fall 2017 Rupal Shah, MD, Vadodara, India Figure 1. Change in BCVA over time My 9-year SMILE journey I t's been a long time since Rupal Shah, MD, Va- dodara, India, started her journey with SMILE using the VisuMax femtosecond laser. Some things, she said, have remained unfulfilled, but certain dreams did come true. Dr. Shah started her SMILE journey 9 years ago, and she considers it the most fortunate thing that has hap- pened to her. Performing and being able to contribute mean- ingfully to the development of the procedure as well as mak- ing great friends, traveling, and developing as a person have all made SMILE the most fulfilling part of her professional life. Changes over the years Nine years ago, she said, SMILE was just a possibility, beginning as FLEx, femtosec- ond lenticule extraction. The laser was much slower—just 200 kHz against today's 500 kHz. The laser also used a re- verse scanning pattern, higher energy, and lower spot and track spacing. The scanning pattern would begin at the center, moving to the periphery. The second pass would then move from the periphery to the center, taking much longer to complete than the laser does today. The incision length was also much larger, allowing the surgeon to lift a flap and re- move the lenticule. After a few procedures, Dr. Shah realized that FLEx lenticule extraction had few advantages over conventional LASIK surgery, and so proceeded to perform pseudoSMILE within a month from starting FLEx, and SMILE just a few months later. What made the difference from those early days, Dr. Shah said, was the change in scanning pattern. The original scanning pattern allowed bub- bles to accumulate in the cen- ter, distorting the tissue before the second incision laser pass. This resulted in distorted corne- al topography and delayed visual recovery. Changing the scanning pattern produced starkly dif- ferent results—from just 65% achieving a 1-day postop un- corrected visual acuity (UCVA) equivalent to the preop best corrected visual acuity (BCVA) to 83% visual recovery. This was the procedure's eureka moment, changing the whole scenario. The test of time Long-term follow-up is particu- larly important for establishing the value of SMILE in refractive practice; with the procedure being done primarily for young individuals, refractive changes can occur over the years. Fur- thermore, SMILE is competing with earlier procedures such as PRK and LASIK, which are more than 20 years in clinical practice. Dr. Shah has thus been conducting an ongoing study to see how the procedure stands the test of time. To date, out of 132 patients who underwent SMILE or FLEx for myopia or myopic astigmatism with spherical equivalent less than –10 D between August 2008 and 2009, 30 returned for a fol- low-up in April and May 2016. All patients had been treated with the 200-kHz laser, most with the old scanning pattern. The results, Dr. Shah said, even with the older techniques, were astonishing. In 7.5 years, the refraction remained stable, with very little deviation from that achieved at 6 months and 1 year postop. In terms of efficacy and safety, the UCVA and BCVA, respec- tively, changed very little over time, with a non-statistically significant improvement in BCVA over time (Figure 1). Topography studies further showed true 6-mm zones, while induced higher order ab- errations were equal to or less than LASIK treatment. In terms of subjective satisfaction, 100% of patients reported satisfaction with the procedure, saying they would recommend the procedure to friends or relatives, four patients reported dryness or grittiness in their eyes, and two patients reported difficul- ties driving at night. No other subjective symptoms were reported. SMILE: 9 years on SMILE has come a long way over the years, with better surgical techniques and a faster laser with better energy parameters and an improved scan pattern. However, early results are, in Dr. Shah's ex- perience, as good as or better than other competing refractive procedures—even after several years. In April 2017, Carl Zeiss Meditec (Jena, Germany) conducted a user meeting in Singapore. More than just a showcase for their latest technologies, the company's user meeting has grown into a venue for peer-to-peer sharing of information among the world's top ophthalmic surgeons. The first symposium of the meeting focused on SMILE, small incision lenticule extraction, performed with the ZEISS VisuMax femtosecond laser, and how this cutting-edge procedure is redefining the field of refractive surgery. 100 75 50 25 0 <=20/15 <=20/20 <=20/25 <=20/30 Six months 7.5 years

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