After performing over 50,000 refractive surgeries, including LASIK and its refractive variations Epi-LASIK/PRK, Visian ICL, Raindrop Inlay, Kamra Inlay, and SMILE, I’ve learned that each technique has its unique role in treating specific vision problems. On this page, I describe the SMILE LASIK procedure, and its distinct advantages and limitations compared to LASIK/Epi-LASIK. The SMILE LASIK procedure represents “another tool in our toolbox” for helping my patients achieve a lens-free lifestyle.
Summary of SMILE LASIK
SMILE is an FDA-approved laser vision correction procedure to treat pure nearsightedness without visually-significant astigmatism (0.50 D or less astigmatism). The VisuMax laser is the only femtosecond laser that is approved for the SMILE procedure, which is a minimally-invasive, bladeless, painless, flapless, single-step laser procedure to treat nearsightedness. But for patients with visually-significant astigmatism or farsightedness, LASIK and Epi-LASIK/PRK are more effective options than SMILE. During your consultation, I will be able to determine the best refractive option for you.
Animated video of the SMILE procedure
What’s it like to undergo the SMILE procedure?
Prior to the procedure, numbing eye drops are instilled and an oral sedation pill is offered to minimize anxiety. Similar to LASIK, the SMILE procedure takes about 15 minutes to complete for both eyes. Fortunately, patients typically “feel nothing” during the SMILE procedure, but eyes may feel scratchy and irritated for a few hours after SMILE. Patients can expect to have “functional vision” and return to work the next day, but it can take a few days before vision seems “very clear”. Afterward, antibiotics, anti-inflammatory and lubrication eye drops are used to promote rapid healing.
Specifically, how does SMILE treat nearsightedness?
For SMILE, I use the same femtosecond laser that I typically use for LASIK (the VisuMax femtosecond laser), but with a few distinct differences. During the SMILE procedure, the VisuMax laser sculpts a thin lens-shaped “refractive lenticle” that corresponds to one’s optical correction (red area seen below). Simultaneously, the VisuMax laser creates a 4-millimeter micro-opening so the refractive lenticle can be removed. For patients with a larger amount of nearsightedness, the refractive lenticle will be thicker compared to a mild correction. Unlike LASIK, the SMILE procedure does not use a wavefront excimer laser, just the VisuMax femtosecond laser. SMILE is an abbreviation for “SMall Incision Lenticule Extraction and it is analogous to “slipping out a contact lens-shaped lenticle from the cornea”.
Who is a good candidate for SMILE?
Age 22 years or older
Myopia from -1.00D to -8.00D with no more than -0.50D of astigmatism. Generally, patients that are happy with soft contact lenses that don’t treat for astigmatism (soft non-toric contact lenses)
Relatively stable glasses prescription in the last 12 months
Normal topography and corneal thickness (similar to what is required for LASIK)
No previous eye surgery
Good general and eye health
In a retrospective analysis consisting of 200,000 patients that were interested in having a laser vision correction procedure between 2015-2017, approximately 30% of patients were within the FDA-approved treatment range for SMILE. The remainder of patients were either too nearsighted (>-8.0 D), or had farsightedness, or had visually-significant astigmatism (>0.5 D astigmatism) for SMILE. Conversely, about 93% of patients are within the FDA approved treatment range for LASIK/Epi-LASIK, which includes -12.0 diopters nearsightedness, +6.0 diopters of farsightedness, and 6.0 diopters of astigmatism.
Side-By-Side Comparison of Epi-LASIK, All-Laser LASIK and SMILE LASIK
When making apples-to-apples comparisons, clinical studies have shown that the final visual outcomes, results and safety are quite similar between LASIK, Epi-LASIK and SMILE.