Updated on  February 10, 2023
5 min read

ReLEx SMILE Surgery: Procedure, Results and Costs

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What is ReLEx SMILE Eye Surgery?

ReLEx SMILE eye surgery stands for refractive lenticule extraction small incision lenticule extraction surgery. It is a type of refractive eye surgery, meaning it can correct vision issues.

ReLEx SMILE is a relatively new surgery. Doctors first performed it in 20081.

SMILE surgery uses a femtosecond laser, or a high-speed, short-pulsed laser, to remove a section of the cornea. The shape changes when part of the cornea is removed and refractive errors are corrected. 

The U.S. Food and Drug Administration (FDA) approved the use of the VisuMax Femtosecond Laser in 2016 for the SMILE procedure.2 

What Refractive Errors Can SMILE Correct?

In the U.S., SMILE has been approved to treat myopia (short-sightedness) since 2016. This occurs when people can see things clearly close up but are unable to see things clearly from a distance.

Myopia can occur when the eye focuses light directly in front of the retina. It is often due to a too-long eyeball, a too-steep cornea, or a combination of the two.

Since 2018, however, the FDA has approved the use of SMILE for treating astigmatism in addition to myopia.3 Astigmatism is when an irregularly shaped cornea causes blurry vision.

SMILE Procedure: What to Expect

Before surgery, your ophthalmologist will talk through expectations. This is to make sure they are realistic and you’re not disappointed with the results. 

Some people might still have to wear glasses or contact lenses for certain activities after surgery. But the majority of people can carry out most of their day-to-day tasks without them.

Preparing for Surgery

After discussing and managing expectations, your ophthalmologist will conduct an eye exam to ensure you are suitable for the procedure. This will include:

  • Conducting an eye test. The ophthalmologist will test your level of nearsightedness to make sure SMILE will correct it. They will also look for other refractive errors that could impact surgery, or that SMILE could make worse. 
  • Cornea mapping. To program the computer-based laser, your ophthalmologist will take several measurements, including the thickness and surface mapping of the cornea.
  • Measuring your pupil size. Finally, your ophthalmologist will measure the size of your pupil.

Before and During Surgery

Before surgery, your doctor will administer numbing eye drops. They will use a speculum to prevent you from blinking.


The procedure consists of three main steps:

  1. A femtosecond laser will create a thin layer, the shape of a contact lens, inside the intact cornea. This is called a lenticule.
  2. It will also make a small incision (approximately 4mm long) in the cornea.
  3. The ophthalmologist will remove the lenticule through the incision.

SMILE laser eye surgery usually takes around 10 to 15 minutes per eye. Ophthalmologists typically only use the laser for about 30 seconds.4

After Surgery (Recovery)

Most people will have hazy vision right after the procedure. Typically, driving the day after the procedure is safe, but this depends on the person.

It is important to avoid certain things that may irritate your eyes, such as:

  • Television
  • Cell phones
  • Tablets
  • Computer screens

Avoid these devices for around 2 to 3 days after the procedure.

Side Effects and Risks of ReLEx SMILE 

As with all surgeries, the ReLEx SMILE procedure has side effects and risks, although research suggests they are minimal.5

Some of the most common side effects include:

  • Inflammation around the treated area
  • Glare and halos around lights, particularly at night
  • Debris where the corneal disc was removed
  • Infection

One frequent side effect of most refractive eye surgeries is dry eye. Research suggests there is a nonsignificant reduction in postoperative tear production for people who undergo SMILE. This means that compared to other procedures such as LASIK, the risk of developing dry eye is minimal.5

What is the Success Rate of SMILE Surgery?

The ReLEx SMILE procedure has not been around as long as other types of vision correction surgeries. The long term success rate is still under investigation. 

One study observed people who had SMILE surgery 3 years prior. It showed that vision was better than or equal to 20/20 in 90% of participants.6 Different studies suggest a range of 65 to 100% efficacy for SMILE.

ReLEx Smile vs. LASIK 

An alternative to SMILE is LASIK (laser-assisted in situ keratomileusis).


SMILE and LASIK are similar in many ways: 

  • Risk. Both procedures have minimal risk.
  • Downtime. Both procedures allow people to resume daily activities within a few days post-surgery.
  • Cost. Generally, the price of LASIK and SMILE are comparable. 
  • Recovery time. Most people find that they have 20/20 vision within a couple of days, regardless of if they have SMILE or LASIK.
  • Quick. Both procedures take around 10 to 15 minutes per eye and require no inpatient stay. People can go home shortly after the surgery.


While SMILE and LASIK have many similarities, there are also reasons why someone may choose one procedure over the other. 

Major differences include:

Is only approved in the United States for correcting myopia (nearsightedness) and astigmatism.Can correct many refractive errors including myopia (nearsightedness), astigmatism, and hyperopia (farsightedness).
Uses a femtosecond laser.Uses both an excimer and femtosecond laser.
Does not require a corneal flap but instead makes an incision that is typically less than 4mm long.Creates a flap in the cornea before reshaping it to correct refractive errors.
Fewer postoperative restrictions; for example, people can play outdoor sports without worrying about the flap.Requires postoperative restrictions to ensure the flap does not dislodge.
People can return to outdoor activities and swimming within the first week after the procedure.Surgeons may advise people to wait between 15 days to a month to resume outdoor activities and swimming.

Because SMILE is relatively new, most surgeons recommend LASIK instead. Further research is necessary to understand the long-term outcomes of SMILE.


ReLEx SMILE is a newer alternative to existing refractive eye surgeries like LASIK. The outcomes are comparable to traditional surgical methods and have lower risks of complications such as dry eye.7 

All procedures have benefits and risks, and some people may not be a good candidate for all surgeries. Talk with your ophthalmologist to determine which option is best for you.

Updated on  February 10, 2023
7 sources cited
Updated on  February 10, 2023
  1. Shah, R. “History and Results; Indications and Contraindications of SMILE Compared With LASIK.” Asia-Pacific Journal of Ophthalmology (Philadelphia, Pa.), 04 Oct. 2019
  2. FDA approves VisuMax Femtosecond Laser to surgically treat nearsightedness.” U.S. Food & Drug Administration, 13 Sept. 2016
  3. ZEISS Receives FDA Approval for ReLEx SMILE: Expanding Myopia Treatment to Patients with Astigmatism.” Carl Zeiss Meditec AG, 05 Oct. 2018
  4. Turbert, D. “What Is Small Incision Lenticule Extraction?” American Academy of Ophthalmology, 27 May 2021
  5. MS;, Sambhi RS;Sambhi GDS;Mather R;Malvankar-Mehta. “Dry Eye after Refractive Surgery: a Meta-Analysis.” Canadian Journal of Ophthalmology. Journal Canadien D'ophtalmologie, U.S. National Library of Medicine.
  6. Han, T. et al. “Three-year outcomes of small incision lenticule extraction (SMILE) and femtosecond laser-assisted laser in situ keratomileusis (FS-LASIK) for myopia and myopic astigmatism.” British Journal of Ophthalmology, 22 Mar. 2019
  7. Ang, Marcus, et al. “Refractive Surgery beyond 2020.” Eye (London, England), Nature Publishing Group UK, Feb. 2021.
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