SMILE Eye Surgery - What You Need to Know

Due to this lack of proven clinical benefit to our patients, SMILE is not a part of our practice at this time. We continue to evaluate this procedure as it advances.

The Conlon Eye Institute is committed to remaining at the forefront of eye care innovation. This commitment means evaluating the latest technology for proven clinical benefits. When the laser eye surgery procedure, SMILE, emerged, it was marketed as providing advantages over LASIK. As the scientific literature stands, such claims have not been substantiated, and some of the procedures’ limitations have surfaced.

The percentage of people getting 20/20 or better uncorrected visual acuity is, in my opinion, the most important outcome measure and an absolute requirement for a successful refractive surgery platform.  Simply put, SMILE does not currently meet this requirement. I hope, one day it does, because while LASIK and PRK are time-tested excellent treatments, we are continuously looking for ways to improve.

Presently, the scientific literature supports advanced customized wavefront-guided LASIK procedures for improved visual acuity outcomes and higher quality of vision.

Please feel free to contact us with any questions or for more information regarding the SMILE procedure.



Q: What is SMILE?

SMall Incision Lenticule Extraction (SMILE) is a laser eye surgery used to correct nearsightedness (myopia) and astigmatism. This procedure uses a femtosecond laser to create a lenticule, a disc-shaped piece of tissue, in the cornea. The laser is then used to create a small arched incision in the cornea’s surface. The lenticule is then extracted through this incision and discarded. The removal of this lenticule reshapes the cornea, thus correcting vision.

Q: Who is a candidate for SMILE?

Currently, SMILE is available to correct nearsightedness and small amounts of astigmatism. However, it is challenging to correct low levels of myopia and myopic astigmatism using SMILE due to the thinness of the corneal lenticule. At this time, SMILE cannot correct farsightedness (hyperopia), mixed astigmatism, or large amounts of astigmatism. It is essential to receive a consultation to determine whether SMILE is right for you as with any procedure. For patients with vision conditions outside of the range treated by SMILE, LASIK may be an option. Check out our LASIK page for more information on further criteria for LASIK candidates.

Q: What does the newness of SMILE mean for patients?

SMILE was approved by Health Canada in 2015, compared to LASIK in 1994. Because of its newness, SMILE is typically marketed as the “next generation” laser eye surgery. However, newness does not necessarily mean improvement, and SMILE technology is currently in its early development.

The longevity of LASIK is a testament to its strong track record rather than an indication of outdatedness. LASIK has also undergone continuous improvements over time and is on its fifth generation of technology. There is a current ten-year trend of improving visual acuity and safety with LASIK. Even though SMILE is a newer procedure, LASIK has been continuously refined throughout its lifetime to offer the best vision possible.

Q: How safe is SMILE compared to LASIK?

There are no dramatic differences in predictability and efficacy between SMILE and LASIK at this time. SMILE has been less well-studied, and further large-scale studies are necessary to understand the safety profile better.

At this time, there have been several reported cases of corneal ectasia associated with SMILE. Corneal ectasia is a rare complication of laser eye surgeries. It results from abnormal weakening of the cornea and can lead to severe vision problems. Further study needs to be done to determine the actual risk of ectasia associated with SMILE.

There is an increased risk of decentered treatments with SMILE. Decentration of the treatment can cause symptoms such as blurred vision or ghosting after surgery. The advanced eye-tracking system on the LASIK excimer laser makes instances of decentered ablations extremely rare. Eye-tracking technology is not available with SMILE surgery. The surgeon cannot make further centration adjustments once the SMILE suction ring is applied to the eye.

Q: Is SMILE less invasive than LASIK?

The use of a flapless procedure was thought to be less invasive and better protect the cornea’s structural integrity. However, although the corneal incision is smaller in diameter with SMILE, the initial lenticule incision is deeper into the cornea than the LASIK flap incision. Additionally, there is more tissue removal in SMILE surgery and a more significant reduction of corneal strength than LASIK surgery, which is especially true for lower corrections. As a result, SMILE surgery is essentially equally as invasive as LASIK surgery.

Q: What are the visual results of SMILE versus LASIK?

In general, the visual results of SMILE surgery are similar to LASIK. The majority of the scientific and clinical data compares SMILE to 1st and 2nd generation LASIK surgery results. The studies show that the visual results are better with the modern, 5th generation LASIK lasers than with SMILE. Interestingly, in the US FDA clinical trials, fewer patients achieved 20/20 vision after SMILE than LASIK.

The most common reason for reduced vision after any laser eye surgery is under-correction. The rate of under-correction with SMILE is slightly higher than LASIK; this is especially true when correcting astigmatism prescriptions and happens as often as 1 out of 10 patients that undergo SMILE.

Although it is possible to achieve 20/20 eyesight or better with both procedures, LASIK offers the ability to perform customized ablations using wavefront and topography-guided (5th generation) technologies. This technology is not yet available with SMILE. These customizable techniques can achieve crisper visual quality by smoothing the topographical irregularities that affect visual clarity.

Due to corneal variability, two individuals may have 20/20 eyesight, but this does not mean their vision will be of the same quality. Advanced customized wavefront-guided LASIK offers significant advantages in visual outcomes for individuals with irregular corneal topography, previous laser eye surgery, or high angle kappa.

Q: What are the benefits of a flapless procedure (PRK)?

The main benefit of a flapless procedure (PRK) is that it is not susceptible to flap complications sometimes associated with severe eye trauma. Typically, such flap issues do not occur with mild to moderate eye trauma, i.e. the level of trauma associated with sporting injuries. However, there have been reported occurrences of flap problems for patients facing other severe eye injuries. The advancement of femtosecond laser (i.e. bladeless) LASIK flaps has significantly decreased the chances of a flap complication.

Q: Does SMILE improve incidences of dry eye?

Currently, SMILE may offer the advantage of decreased dry eye symptoms in the first six months after surgery. Although uncommon with laser eye procedures, postoperative dry eye typically occurs as corneal nerve disruption inhibits corneal sensitivity, leading to a lack of lubrication signalling. It is thought that since fewer corneal nerves are disturbed using SMILE, this leads to a decreased risk of dry eye. However, levels of postoperative dry eye are typically mild regardless of the kind of laser eye surgery. Even after LASIK, dry eye is largely temporary. Six months after surgery, most patients return to their preoperative levels of dryness regardless of the procedure. In the long term, SMILE has no significant benefit over LASIK in terms of dry eye.

Q: What is the difference in visual recovery time between LASIK and SMILE?

LASIK offers a faster visual recovery, with most patients returning to 20/15 to 20/20 on the first day after surgery. In comparison, SMILE surgery patients are typically 20/25 to 20/30 on the first day, with gradual improvement over the following weeks. Some SMILE patients may face a prolonged recovery period. The difference in recovery time is significant for patients looking to return to their daily routines as quickly as possible.

Q: What enhancement options are available after SMILE?

Sometimes after laser eye surgery, a “touch up” (a.k.a. enhancement) is required. After SMILE, enhancements are done using PRK (photorefractive keratectomy). In comparison, LASIK can be redone on patients that previously had LASIK surgery. Although it’s a safe and effective option, PRK involves a more extensive recovery time than LASIK and SMILE.

  • Generation of Technology
  • Customized Wavefront-Guided Treatment
  • Myopia Correction
  • Hyperopia Correction
  • Astigmatism Correction
  • Treatment Smoothness


  • 5th
  • Yes
  • Yes
  • Yes
  • Yes
  • Smooth


  • 5th
  • Yes
  • Yes
  • Yes
  • Yes
  • Smooth


  • 1st
  • No
  • Yes
  • No
  • Low amounts only
  • Rough