What is SMILE Eye Surgery?
SMILE stands for small incision lenticule extraction and is a refractive procedure. SMILE helps treat many refractive errors, including myopia (nearsightedness), hyperopia (farsightedness), presbyopia (due to aging of the eye), and astigmatism.
Unlike LASIK, this procedure does not require the use of an excimer laser. Instead, it uses a femtosecond laser to form a lenticule (disk-shaped corneal tissue) for later extraction. It does not create a corneal flap that is key in LASIK procedures.
The Food and Drug Administration (FDA) in the United States approved SMILE for refractive myopic corrections in 2016 and compound myopic astigmatism in 2018. This type of refractive surgery has proven popular against other laser vision correction procedures. SMILE offers quicker recovery of post-op dry eye, restoration of corneal nerves, and possible biomechanical advantage.
SMILE Laser Eye Surgery Procedure Steps
Before the actual procedure, the ophthalmologist will perform some eye exams to assess vision and take measurements. Some of these measurements can include pupil size, cornea thickness, and much more related to the cornea’s surface.
During SMILE, the following steps will occur:
- The eye surgeon will set the laser according to the specific measurements necessary for the eye. A possible laser used during the procedure is the VisuMax femtosecond laser.
- Eye drops will be administered to numb the eyes.
- The eye surgeon will place an eyelid holder on the eye to prevent blinking.
- A suction ring raises and flattens the cornea and helps maintain the eye in place.
- The eye surgeon will then use the laser to form a lenticule (a disk-shaped piece of corneal tissue) below the eye’s surface.
- The laser then performs a small incision in the cornea, giving access to the lenticule just created.
- The eye surgeon will then extract the lenticule through the incision, which reshapes the cornea.
The procedure does not take longer than 15 minutes.
Common Side Effects of SMILE
Side effects will not vary much to those found with LASIK or other laser surgical procedures. Individuals who undergo SMILE may expect to experience:
- Halos surrounding lights
- Dry eye
- Tissue inflammation
- Debris where tissue was removed
- Over-correction or under-correction
- Ocular pain/soreness
- Loss of best spectacle-corrected visual acuity (BSCVA) or contrast sensitivity
Potential Complications of SMILE
Complications are not frequent during the SMILE procedure. Some individuals have reported epithelial abrasions, small tears at the site of incision, and perforated caps. However, none of them have experienced poor visual changes.
Over-correction or under-correction may occur. In such cases, contact lenses or regular eyewear may be suitable, or individuals may have to consider retreatment with a laser-guided procedure or surface PRK.
There is also the rare risk of worse vision (even with eyewear) and blindness.
Unlike LASIK, there is no risk of corneal flap displacement. The SMILE procedure does not require the formation of such a flap.
Who is a Good Candidate for SMILE Eye Surgery?
SMILE eye surgery will be suitable for some individuals more than others. For example, if individuals have an active lifestyle or job, SMILE may prove better than LASIK or related procedures. With SMILE, there is no risk of corneal flap displacement.
However, more criteria can help determine eligibility for SMILE eye surgery, including:
- 22 years or older
- No change in eye prescription during the past year
- Myopia should be between -1 and -10, and no more than 3 diopters of astigmatism
- Good eye health, especially the corneas
- Realistic expectations about procedure outcomes for vision correction
Individuals who are not good candidates for SMILE eye surgery include those with:
- Skin or other diseases that may affect recovery
- A cataract affecting sight
- Uncontrolled diabetes
- Advanced glaucoma
- Corneal abrasions
- A history of particular eye infections
- Excessive scarring or keloid formation (overgrowth of scar tissue)
- Women who are pregnant or nursing
Pros and Cons of SMILE
SMILE eye surgery has more advantages than downsides.
For example, the procedure makes a small incision (2-3 mm) in the eye, keeping corneal nerve severance at a minimum. This contrasts with LASIK, which includes the cutting of a corneal flap.
That said, SMILE does not require a corneal flap. No corneal flap translates then to no risk of corneal flap dislodgement during contact sports or work-related accidents.
Additionally, because the eye surgeon does not disturb the cornea’s surface very much in SMILE, long-term dry eye is often less common with SMILE than with other laser-guided procedures.
A disadvantage of SMILE is the costs. Because the procedure is considered an elective procedure, it does not usually receive coverage from insurance companies.
LASIK vs. SMILE vs. PRK
LASIK, SMILE, and PRK are all procedures that help to correct refractive errors. However, one surgical procedure may be better for some individuals than for others.
Speaking with an ophthalmologist and undergoing an eye exam can help determine the best procedure for an individual’s unique needs.
That said, differences do exist among the three types of refractive surgery. For example, while SMILE and LASIK are similar, SMILE is less invasive and as effective as LASIK. A meta-analysis of randomized controlled trials and comparative studies revealed that SMILE performed better in corneal sensation and tear break-up time than LASIK.
Despite these benefits, both SMILE and LASIK may not work for thin corneas or a corneal surface irregularity. PRK surgery may prove as the most appealing option in this case. Like SMILE, PRK does not disturb as much corneal tissue as LASIK does. Conversely, unlike SMILE and LASIK, PRK requires more follow-up care visits.
SMILE is approved to treat myopia and astigmatism, but those with hyperopia may opt for LASIK/PRK.
In one study, 80% of individuals who underwent SMILE did not need lubricating eye drops at 6-month post-op, while 43% of individuals who underwent LASIK still did.
How Much Does SMILE Surgery Cost?
SMILE surgery will change in price based on different factors, including:
- The type of laser used
- The eye surgeon’s expertise and experience
- Exclusive discounts, financing offers, or payment plans
- The individual’s vision and other relevant or existing eye or health condition
- Clinic fees, visits before and after surgery, or medications
- Ophthalmology clinic location
- Screening eye exam
On average, individuals may spend between $2,000 and $4,000 for SMILE eye surgery. At UCLA’s Laser Refractive Center, SMILE surgery costs approximately $2,500 per eye.
It is important to remember that price is only one factor to consider when exploring different refractive surgery types. Consulting an eye doctor can help shed light on which surgical route is the most beneficial to good, long-lasting vision.
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