Eyeworld

100 | EYEWORLD | JULY 2021 R EFRACTIVE About the physicians John Doane, MD Discover Vision Center Kansas City, Missouri D. Rex Hamilton, MD Medical Director Hamilton Eye Institute Los Angeles, California Dan Reinstein, MD London Vision Clinic London, U.K. by Liz Hillman Editorial Co-Director T hough it has been available in the U.S. for a fraction of time compared to the well-established laser vision correction procedures PRK and LASIK, SMILE has quickly become the dominant procedure in the practices of many refractive surgeons. John Doane, MD, said about 90% of his refractive practice is SMILE; D. Rex Hamilton, MD, said about 80%; and Dan Reinstein, MD, said about 75%. Dr. Hamilton said the shift to SMILE in his refractive surgery patient population has been at his direction, for the most part. He per- formed the first SMILE cases on the West Coast in March 2017. With more recently approved (2018) indications for up to 3 D of astigmatic correction and better energy settings for faster visual recovery, he has been recommending SMILE to nearly all of his myopic patients for at least the last year and a half. Within the last 6 months, he's had patients coming in asking for SMILE without his prior counseling. "The SMILE procedure market share went up by about 60% from 2019 to 2020, from 3% to 7–8%. That's a pretty significant improve- ment in 1 year, particularly in the face of every- thing going on," Dr. Hamilton said. While refractive surgery in general has enjoyed a spike in the months since practices reopened after the COVID-19 pandemic shut- down, why the uptick in SMILE over the last few years? In Dr. Hamilton's view, it's perceived as a safer procedure. There isn't a flap and thus patients aren't worried about flap-related com- plications. Although a flap dislocation is exceed- ingly rare, Dr. Hamilton says it is still a factor in the patient's mind and a barrier to seeking refractive surgery. Even more influential is the dry eye factor, he said. "There's no question, and the literature sup- ports, that the severity and duration of dry eye is significantly less. I tell patients 6–12 months of dryness with LASIK, 1–3 months with SMILE and of a lesser degree. [Dry eye is] one of the aspects of LASIK that keeps patients on the sidelines," he said. "At this point, more than 400 peer-reviewed articles have been published on SMILE, and overwhelmingly SMILE has shown advantages with regard to induction of dry eye or recovery of this symptom and biomechanical strength compared to LASIK," Dr. Doane said. "SMILE has quicker healing and thus [more] patient acceptance than PRK." Dr. Reinstein said that any myopic eye, without the usual contraindications for refrac- tive surgery, is a candidate for SMILE. The pro- cedure is especially desirable for eyes that might be slightly dry, for those with large pupils, and/ or for patients who play contact sports, he said. From a surgeon standpoint, Dr. Hamil- ton said the initial slower recovery of SMILE compared to LASIK might have kept refractive surgeons from adopting the technology and technique when it was first approved. Newer energy settings make this a non-issue now, Dr. Hamilton said. He recently published an article comparing visual acuities and higher order aberrations of his LASIK and SMILE patients on postop day 1 and month 1. 1 The study found visual acuities were equivalent on postop day 1 and month 1 between the procedures. It also showed less spherical aberration induction at month 1 with SMILE vs. LASIK. "That was a big hurdle for SMILE to get over," Dr. Hamilton said, noting how it used to take a week or longer for SMILE patients to reach 20/20 vision. "Now with the newer ener- gy settings, we have less issues with inflamma- tion postoperatively. Opaque bubble layer (the whitening of the cornea) is much less with the newer energy settings, and that translates to faster vision recovery." Dr. Hamilton called this the most important new development for SMILE. Another attrac- tive feature, he continued, is its accuracy and predictability. "If you talk to refractive surgeons around the world who do SMILE and LASIK, they will tell you that the enhancement rate with SMILE is one-third that of LASIK," the latter of which already has a low enhancement rate. Dr. Doane also mentioned the lower enhancement rate experienced with SMILE. The reason for this, Dr. Hamilton explained, could be that the tissue is not being exposed to the environment for a variable length of time as it is when the flap is lifted in LASIK and the SMILE: Acceptance, updates, and more

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