Truly SMILE(ing) After Eye Surgery?

LASIK eye surgery is the most common refractive eye surgery used to fix one’s vision today. However, the latest surgical procedure, SMILE has increasingly become popularized within the ocular community. SMILE stands for Small Incision Lenticule Extraction, which is where a small incision is made around the cornea of the eye to extract the lenticule for reshaping the cornea and allowing for clearer vision. However, since it is a newer procedure, first performed in Germany in 2007 and more widely performed starting in 2011, there is still a lot of room for error [1,4]. Prospective patients are advised to do thorough research before deciding to get this procedure.


LASIK and SMILE are procedures that improve one’s vision so that they no longer have to rely on glasses and contacts. Both are known to have a fast procedural time, taking a maximum of 15 minutes for both eyes in LASIK and 10 minutes total for SMILE [2,3]. The visual recovery time is also very fast, starting even a day after surgery for LASIK and taking up to about 3 days for SMILE [2]. The most common post-operative discomforts include the feeling of scratchiness, the sensitivity to bright lights, and involuntary tears which can last about 4-5 hours after surgery for LASIK and 1-2 hours for SMILE, although actual times may vary between people [2]. Therefore, it is important to wear sunglasses and have a designated driver after the procedure. The pain may feel more severe than ophthalmologists tend to claim, which is something to keep in mind as well.


SMILE has recently been the recommended choice by ophthalmologists for patients that are eligible for either LASIK or SMILE (thick cornea), who have high myopia going up to -10 diopters and astigmatism of up to 3 diopters, and/or play sports because there’s less exposure of the eye to the outside environment during the surgery [3]. Instead of requiring two lasers for the procedure as is the case for LASIK, SMILE uses only the femtosecond laser, a more effective alternative because it it internally carves out a lenticule in the corneal stroma instead of creating a flap on the outside surface [1]. Hence, SMILE offers the avoidance of flap complications and severe cases of dry eye, a common postoperative complication [1]. Studies have also shown that SMILE has high efficacy, safety, and predictability like LASIK, but fewer effects of halo vision and night blurriness, which are common in LASIK patients [4].


However, it is crucial to note that both intraoperative and postoperative complications still exist with SMILE. I have experienced some of these complications this past summer after getting the procedure done in South Korea. I had severe myopia with a prescription of -8 and astigmatism in my right eye. I was only 18 years old and usually ophthalmologists recommend it to patients who are older than 22 years old since eye prescriptions have not yet reached a stable point [3]. Despite my age, the eye exams confirmed that I had no eye problems so I agreed to do the procedure blindly without doing my research. My desire to finally be free of glasses and contacts got the better of me.


After the surgery, it resulted in much disappointment. Weekly visits to my ophthalmologist always ended with him saying, “don’t worry, your vision will get better the following week.” But it never did. I returned to the United States at the end of summer needing a glasses prescription of -1.25, which was a lot better than -8, but not the 20/20 vision I had envisioned.


Frustrated with this outcome, I started doing the research I should have done before getting the procedure with the hopes that prospective patients would not make the mistakes that I did. In a clinical study that compared the differences in visual recovery after SMILE eye surgery to patients’ preoperative vision, Tay et. al. found that, although after 1-3 months, patients with lower myopia and patients with higher myopia both reached very good visual outcomes, 41.2% (88/214 eyes) did experience undercorrection of their vision [5]. Although not confirmed by my ophthalmologist back in Korea, I believe that my astigmatism could have been undercorrected, which would explain my suboptimal vision. Possible factors that could have caused this undercorrection are imperfect centering of the optical zone in the eye before surgery or a slight movement of the patient during the procedure [4,6]. SMILE does have a steeper learning curve, which also could have had an influence. But it would be unfair to only hold the ophthalmologist responsible when I, the patient, could have better followed my post-surgery instructions by reducing my screen time. I still wonder if that would have actually helped my outcome or if it was a way for the ophthalmologist to justify what happened.


All in all, I should have done my research before going into the procedure. However, on the positive side, a SMILE retreatment in the future could possibly help. I can see much better without any visual metrics and I am planning to get contact lenses prescribed soon for personal convenience. Hopefully in the upcoming years, more will be known about SMILE’s visual recovery curve and methods on how to reduce complications or unfavorable outcomes so that prospective patients can form realistic expectations and have a better understanding of SMILE.


References


1. Shah, R. (2019). History and results; indications and contraindications of smile, compared with LASIK. Asia-Pacific Journal of Ophthalmology, 8(5), 371–376. https://doi.org/10.1097/01.apo.0000580132.98159.fa YouTube. (2020).


2. LASIK, PRK, SMILE: What's the difference? Retrieved March 14, 2022, from https://www.youtube.com/watch?v=PZcCysop5FE.


3. Turbert, D. (2021, May 27). What is small incision lenticule extraction? American Academy of Ophthalmology. Retrieved March 14, 2022, from https://www.aao.org/eye-health/treatments/what-is-small-incisionlenticule-extraction


4. Chow, S. S. W., Chow, L. L. W., Lee, C. Z., & Chan, T. C. Y. (2019). Astigmatism correction using smile. Asia-Pacific Journal of Ophthalmology, 8(5), 391–396. https://doi.org/10.1097/01.apo.0000580140.74826.f5


5. Tay, E., & Bajpai, R. (2020). Visual recovery after small incision lenticule extraction (smile) in relation to pre-operative spherical equivalent. Graefe's Archive for Clinical and Experimental Ophthalmology, 259(4), 1053–1060. https://doi.org/10.1007/s00417-020-04954-8


6. Ang, M., Farook, M., Htoon, H. M., & Mehta, J. S. (2020). Randomized clinical trial comparing femtosecond LASIK and small-incision lenticule extraction. Ophthalmology, 127(6), 724–730. https://doi.org/10.1016/j.ophtha.2019.09.006

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