SMILE Eye Surgery May Leave You Little to Smile About

The SMILE (Small Incision Lenticule Extraction) procedure involves reshaping the cornea by removing a small lens (lenticule) from the central corneal layer. The process uses a femtosecond laser and extracts the lenticule through four small incisions on the corneal surface. SMILE patients typically heal within several days.

The net result, as is the case with LASIK, is that the cornea is reshaped to correct the refractive (or focusing) errors in your vision.

How is SMILE laser eye surgery different from LASIK?

One critical difference between SMILE and the LASIK procedure is that SMILE can ONLY correct simple forms of nearsightedness (myopia). SMILE cannot correct farsightedness, significant astigmatism, high nearsightedness, or other vision deficits commonly known as Higher-Order Aberrations. These can only be corrected using more advanced LASIK laser vision correction technology.

How does LASIK work?

LASIK (Laser-assisted in situ keratomileusis) differs from SMILE in that it uses two different lasers to create a more precise outcome. First, a femtosecond laser forms a microscopically thin hinged flap from the outer (epithelial) surface of the cornea. The corneal flap is then folded back to expose underlying corneal tissue (the stroma). Next, an excimer laser precisely sculpts the stroma using gentle UV rays so the cornea can focus light more precisely.

A sophisticated computer program uses space-age technology to measure both the topography and refractive error of over 1200 zones in the cornea to create a unique surgical plan for each eye. This computer program also guides the excimer laser. The corneal reshaping procedure takes under one minute per eye, after which the flap is gently settled back into place and heals on its own.

Visual recovery from LASIK is much quicker than with SMILE. Most patients are comfortable enough to return to work the next day instead of the two or three days typical of SMILE patients.

SMILE claims quicker recovery and less risk, is this true? 

No. SMILE advertising claims that patients are able to return to their daily activities faster than LASIK due to the small incisions involved. Advertising says that its patients heal faster and have quicker recovery times than LASIK. But research has shown this is inaccurate on two fronts.

First, studies have shown that LASIK patients are able to return to work (or even go to the gym) the day after surgery. They’ve also shown that LASIK patients experience better early recovery of vision as compared to SMILE patients. Studies have demonstrated that final SMILE visual outcomes take longer to achieve than LASIK and can take one month or more to achieve peak levels.

Secondly, SMILE claims of a smaller incision (and thus quicker wound recovery) are misleading because SMILE surgery actually involves making four small corneal incisions around the circumference of your iris. The sum of these four incisions creates a longer wound length than a LASIK incision. Since the total SMILE incision is actually larger, their quicker wound recovery argument goes out the window.

How do SMILE outcomes compare to LASIK?

Research studies comparing SMILE outcomes to those of wavefront-guided LASIK demonstrate that SMILE does not provide better long-term visual and refractive (corrective) outcomes. That’s because only wavefront-guided LASIK is able to address what are known as higher-order aberrations (HOAs). HOAs are optical abnormalities responsible for halos, glare, starbursts, and poor night vision.

In fact, 3% of SMILE patients undergo visual enhancement procedures within two years of their initial surgery and most of these are due to under-correction. During FDA clinical trials in 2016, fewer patients achieved 20/20 vision following SMILE surgery than after undergoing LASIK surgery.

Since SMILE’s introduction, research has shown that under correction occurs in 11% of patients with astigmatism who undergo SMILE procedures. This may be due to the fact that SMILE technology lacks iris registration capacity found in today’s 4th-generation wavefront-guided LASIK. Iris registration maintains the laser beam focus precisely on its target regardless of patients’ eye movement during surgery, ensuring more accurate vision correction.

Risks associated with SMILE vision correction surgery

When considering vision correction surgery options, it’s important to weigh the risks versus benefits of each procedure. Here are some of the common risks associated with SMILE procedures:

Debris left behind

When you consider that SMILE involves separating and extracting tissue from the mid-cornea layer, this adds a unique possible complication of incomplete tissue removal. The presence of residual corneal debris can lead to a corneal abrasion, adhesions, and incisional tears. These will require applying a bandage contact lens and prolonged healing at worst and irritation and inflammation at best.

If caught early, debris can be flushed out with non-invasive treatments. In extreme cases, it may require a second surgical procedure to remove the debris. Often, debris symptoms are temporary, but they can make recovery prolonged and complicated.

Inflammation

While inflammation is a natural consequence of any invasive procedure, in extreme cases inflammation can make recovery more complicated and prolonged. Because SMILE involves more corneal tissue removal than LASIK, there is greater potential for more post-op inflammation. SMILE patients have to be hyper-vigilant for pain or vision problems. Patients should promptly communicate these symptoms to their eye surgeon to avoid further escalation.

Clouded Vision

Because SMILE is designed to treat nearsightedness, it has a higher probability of resulting in hazy vision symptoms. In fact, patients who undergo SMILE surgery tend to describe issues with blurry vision and light sensitivity at one month post-op more often than those who undergo LASIK.

Dry Eyes

The most common side effect reported by all laser surgery patients is dry eyes, and SMILE patients are no exception. SMILE ads claim that their patients experience less post-op dry eye than LASIK patients. That’s because the SMILE approach disrupts fewer corneal nerves. This is a greater concern for people with pre-existing dry eye problems.

In fact, there is no difference in dryness symptoms among post-op SMILE and LASIK patients after six months. Today’s 5th-generation LASIK, known as EagleVision, involves a unique surgical technique designed to minimize post-op dry eye symptoms.

Over or Under Vision Correction

If too much or too little corneal tissue is removed during a SMILE procedure, it can result in over or under correction. Thus making your vision problems worse than before surgery, necessitating retreatment. In the case of overcorrection, your nearsightedness might be replaced with farsightedness.

A significant proportion of SMILE patients report impaired visual acuity up to three months post-op. Unfortunately, they must wait until their vision stabilizes before proceeding with enhancement surgery to fine-tune their vision correction. It’s important to note that once you’ve undergone SMILE, this procedure cannot be repeated. You will need to undergo PRK or LASIK surgery to fix any mis-correction issues.

Corneal weakening and tensile strength loss

A 2016 meta-analysis of 11 clinical studies comparing SMILE and LASIK outcomes found that corneal sensitivity at one week and six months post-op was higher in patients following SMILE procedures as compared to LASIK. A biomechanical study that measured tensile strength of post-op corneas found that the SMILE corneas lost 40% more of their tensile strength after surgery as compared to LASIK corneas.

Corneal warping (known as ectasia) can result in various vision problems and related complications that can only be corrected with glasses or contact lenses. Extreme cases might require a corneal transplant.

The risks of SMILE may outweigh its benefits

SMILE has not been proven to provide better visual outcomes or faster recovery as compared to wavefront-guided LASIK refraction. Therefore, we simply do not recommend it. LASIK offers consistent excellent outcomes. And that’s only one reason why it remains the vision correction procedure of choice among the top ophthalmology practices in the United States.

How to select the best vision correction surgery for me?

This is probably the most important question each patient needs to answer and starts with choosing the best surgeon they can. At Assil Gaur Eye Institute, we pride ourselves in offering the most advanced surgical techniques and state-of-the-art LASIK technology to provide our patients with the safest, most effective procedure designed to optimize their treatment experience and visual outcomes.

Researching refractive surgery can be a daunting task given all of the options currently being marketed and the dizzying claims being tossed about. I can’t stress enough the importance of doing your homework before undergoing an irreversible surgery on your eyes.

We invite you to request your complimentary LASIK consultation at Assil Gaur Eye Institute. Our doctors will closely examine your eyes and ask about your overall health, lifestyle, and vision goals. All of these factors will be taken into account by your surgeon when advising you regarding your eligibility for different vision correction procedures. Our ophthalmologists will also explain how they perform the surgery and answer all of your questions. We want you to feel comfortable that you have the information needed to choose what’s best for you. And, what’s more, that you feel comfortable that you’re in the right hands for any and all of your follow-up needs.

Please call us at (866) 945-2745 or click here to request an appointment or fill out our short LASIK questionnaire.

At AGEI we take our patients’ safety seriously. That’s why our facility’s Covid-19 patient safety procedures exceed all CDC recommendations.

We are conveniently located throughout Southern California and the Los Angeles area. Our ophthalmologists are available at locations in or near Santa Monica and Beverly Hills. We are conveniently located near West Los Angeles, Culver City, West Hollywood, Downtown Los Angeles, Marina del Rey, Pacific Palisades, Malibu, Manhattan Beach, Sherman Oaks, and Encino, to name a few.