Searching “SMILE eye surgery gone wrong” usually means one of two things: you’re researching risks before committing to the procedure, or you’re dealing with an outcome that doesn’t feel right. Either way, you deserve clear, honest answers—not vague reassurances.
SMILE (Small Incision Lenticule Extraction) and its newer iteration SMILE Pro are among the safest refractive surgeries available, with complication rates well below 1% in experienced hands. But “safe” doesn’t mean “risk-free.” Complications do occur, and when they do, knowing what went wrong, why it happened, and what can be done about it makes all the difference. This guide from Visual Aids Centre walks through the real complications—not scare stories—and explains how each one is managed.
Key Takeaways
- Serious SMILE complications are rare—under 1% in published studies using current-generation platforms—but they’re not zero.
- The most common issues include residual refractive error (under- or overcorrection), temporary visual disturbances, dry eye, and difficult lenticule extraction.
- Most complications are manageable with observation, enhancement procedures, or medical treatment when identified early.
- Choosing an experienced surgeon using a current-generation laser platform is the single most effective way to reduce risk.
What Can Actually Go Wrong with SMILE Surgery?
Most online horror stories about SMILE surgery combine isolated cases, outdated techniques, and outcomes that were actually expected temporary symptoms misunderstood as permanent damage. That said, real complications do exist, and pretending otherwise wouldn’t serve anyone well.
The complications associated with SMILE fall into two broad categories: intraoperative (occurring during surgery) and postoperative (developing in the days, weeks, or months after). The intraoperative issues primarily relate to the laser and lenticule extraction process, while postoperative complications overlap with those seen after any corneal refractive procedure. Understanding how SMILE works mechanically helps contextualise why specific problems occur and why most are correctable.
Under-Correction and Overcorrection
This is the most common reason patients feel their SMILE surgery “went wrong.” The procedure removes a precisely calculated disc of tissue (the lenticule) to reshape the cornea, but the cornea’s healing response can sometimes leave a small residual prescription—typically between -0.25 and -0.75 dioptres of under-correction or, less commonly, a slight overcorrection.
Under-correction is more frequent than overcorrection, particularly in patients with higher starting prescriptions (above -6.00 dioptres). It doesn’t mean the surgery failed—it means the biological healing response deviated slightly from the predicted model. Most mild residual errors stabilise within 3–6 months and can be corrected with an enhancement procedure if the remaining error is visually significant. For more on how power changes are managed, see our guide on regression after SMILE surgery.
Difficult or Incomplete Lenticule Extraction
This is a complication unique to SMILE and SMILE Pro. After the femtosecond laser creates the lenticule inside the cornea, the surgeon must separate it from the surrounding tissue and extract it through a small 2–4 mm incision. Occasionally, the lenticule doesn’t separate cleanly—a retained lenticule fragment or a torn lenticule can result.
Why It Happens
Difficult extraction is more common with earlier-generation lasers that used higher pulse energies and wider spot spacing, producing less smooth dissection planes. It can also occur in corneas with unusual tissue characteristics or when the surgeon is less experienced with the technique. The newer VisuMax 800 platform used in SMILE Pro has significantly reduced this issue through faster laser speeds and smoother interface creation.
How It’s Managed
If a lenticule fragment is retained, the surgeon can re-enter the pocket and retrieve it—usually at the same session. In extremely rare cases where a torn lenticule affects the refractive outcome, a secondary procedure (either a SMILE enhancement or a surface ablation like TransPRK) can correct the residual error once the cornea has healed.
Visual Disturbances: Haze, Halos, and Blurry Vision
Some patients experience temporary visual symptoms after SMILE that they interpret as the surgery having gone wrong. These include corneal haze (a mild cloudiness in the treated area), halos around lights at night, starbursts, and fluctuating or blurry vision—especially in the first few weeks.
Mild haze after SMILE is part of the normal healing response and typically clears within 1–3 months. Halos and starbursts relate to the optical zone size relative to the pupil diameter and usually diminish as the cornea stabilises. Persistent blurriness beyond 3 months warrants investigation for residual refractive error, irregular astigmatism, or interface inflammation. Our detailed guide covers the full vision stabilisation timeline after SMILE. If you’re specifically experiencing blurriness in one eye, see why one eye may be blurrier than the other after SMILE.
Dry Eye After SMILE
One of SMILE’s key advantages over LASIK is reduced dry eye risk—because SMILE doesn’t create a large corneal flap, fewer corneal nerves are severed. However, SMILE doesn’t eliminate dry eye entirely. Some patients develop temporary dryness lasting weeks to months, particularly those with pre-existing marginal tear film quality.
Post-SMILE dry eye is typically milder and shorter-lived than post-LASIK dry eye. It’s managed with preservative-free artificial tears, and occasionally with anti-inflammatory drops or punctal plugs for more persistent cases. Patients with significant pre-existing dry eye are usually better served by SMILE Pro’s enhanced nerve-sparing design or may require a comprehensive dry eye workup before any procedure is considered.
Infection and Inflammation
Interface infection (keratitis) after SMILE is exceedingly rare—reported in fewer than 0.02% of cases in large published series. When it does occur, it’s typically caused by entry of microorganisms through the small incision during or immediately after surgery. The contained pocket interface of SMILE actually makes infection less likely than with a full LASIK flap, since the smaller opening provides less exposure.
Non-infectious inflammation (interface haze or diffuse lamellar keratitis-like reactions) can also occur. These respond well to topical steroid drops when identified early, which is why the post-operative follow-up schedule matters. At Visual Aids Centre, our post-operative protocol includes same-day, one-week, and one-month reviews specifically designed to catch inflammatory responses before they affect final outcomes.
Suction Loss During the Procedure
During SMILE, the eye is held steady by gentle suction while the femtosecond laser creates the lenticule. If the patient moves suddenly or the contact interface shifts, suction can be lost mid-procedure—called “suction loss.” This interrupts the laser pattern before it’s complete.
On older platforms, suction loss was more consequential and sometimes required converting to a different procedure. Modern systems like the VisuMax 800 handle suction loss far more gracefully: the laser can often be redocked and the treatment completed from where it left off. The faster 10-second laser time of SMILE Pro (versus ~25 seconds on older systems) also reduces the window during which suction loss can occur. For a deeper understanding of the platform differences, see how to choose between SMILE and SMILE Pro.
Why Do SMILE Complications Happen?
Most SMILE complications trace back to one or more of these factors: surgeon experience (the SMILE technique has a steeper learning curve than LASIK, particularly for lenticule extraction), laser generation (earlier devices produced rougher dissection planes), patient selection (proceeding with borderline candidates increases complication rates), and pre-existing conditions (undiagnosed dry eye, early keratoconus, or unstable prescriptions).
This is why the pre-operative workup matters so much. A thorough evaluation—including corneal topography, pachymetry, tear film analysis, and Pentacam tomography—identifies risk factors that might make a patient better suited to a different procedure. Not every eye is a SMILE eye, and the surgeon who tells you that is the one you want operating on you. Understanding who isn’t eligible for SMILE is just as important as knowing who is.
What to Do If Your SMILE Surgery Didn’t Go as Planned
Don’t Panic in the First Month
Many symptoms that feel alarming in the first 2–4 weeks—blurriness, dryness, light sensitivity, fluctuating vision—are part of normal healing. SMILE recovery is slower than LASIK in the early days because the lenticule pocket takes time to settle. True complications are distinguished from normal healing by their persistence or worsening beyond expected timelines.
Contact Your Surgeon
If you’re experiencing worsening pain, significant vision deterioration, increasing redness, or symptoms that haven’t improved by the expected milestone (usually 1–3 months), contact your surgeon for a thorough examination. Slit-lamp evaluation, topography, and aberrometry can identify the specific issue and guide the treatment plan.
Seek a Second Opinion If Needed
If you’re unsatisfied with the explanation or management from your original surgeon, a second opinion from an experienced refractive specialist is completely reasonable. At Visual Aids Centre, we regularly evaluate patients who had procedures elsewhere and need corrective management. Book a consultation for an independent assessment.
How to Minimise Your Risk
Choose a surgeon with high-volume SMILE experience—the learning curve for lenticule extraction is real, and complication rates drop significantly after the first 50–100 procedures. Insist on a current-generation platform (the Zeiss VisuMax 800 for SMILE Pro offers meaningful safety improvements over older models). Complete the full pre-operative workup and don’t proceed if your surgeon expresses any reservation about your candidacy. Follow every post-operative instruction, attend all scheduled follow-ups, and report symptoms early rather than waiting to see if they resolve on their own. For a comprehensive pre-surgery checklist, our guide on what not to do before SMILE Pro covers everything from contact lens timelines to day-of preparation.
Conclusion
SMILE eye surgery “going wrong” is statistically uncommon, but it’s not impossible. The most frequent issues—residual refractive error, temporary visual disturbances, and dry eye—are manageable and often self-resolving. More serious complications like difficult lenticule extraction, suction loss, and infection are rare and have well-established management protocols. The best protection is choosing an experienced surgeon, using a current-generation laser platform, completing a thorough pre-operative evaluation, and attending all follow-up appointments. When complications do occur, early identification and expert management lead to good outcomes in the vast majority of cases.
Frequently Asked Questions (FAQs)
How common is it for SMILE eye surgery to go wrong?
Serious complications occur in fewer than 1% of SMILE procedures performed with current-generation laser platforms by experienced surgeons. Minor issues like mild residual prescription or temporary dryness are more common but typically resolve with time or straightforward treatment.
Can a failed SMILE surgery be corrected?
Yes. Residual refractive errors can be corrected with enhancement procedures—either a repeat SMILE, surface ablation (TransPRK), or wavefront-guided LASIK. The specific approach depends on the nature of the issue and available corneal thickness.
Is SMILE safer than LASIK?
SMILE eliminates flap-related complications (dislocation, striae, epithelial ingrowth) and causes less dry eye due to fewer severed corneal nerves. However, SMILE has its own unique risks—particularly around lenticule extraction. Overall complication rates are comparable, but the types of complications differ.
What happens if the lenticule tears during SMILE?
A torn lenticule is uncommon with modern platforms. If it occurs, the surgeon can usually retrieve remaining fragments during the same session. If a small fragment is retained, it may be observed or removed in a minor secondary procedure once identified.
How long should I wait before worrying about my SMILE results?
Most visual fluctuation and mild symptoms resolve within 1–3 months. If your vision hasn’t stabilised by 3 months, or if symptoms are worsening at any point, contact your surgeon for evaluation. Final refractive stability is typically reached by 6 months.
