Content is educational and planning-oriented. It does not replace diagnosis, treatment, or personalized medical advice from a licensed healthcare professional. Outcomes vary by individual case.
SMILE complications are generally low—most can be managed effectively when identified promptly.
Intraoperative issues like suction loss (0.5-6.38%) and incision tears (1.8-9.57%) are the most common challenges during surgery.
Postoperative warning signs include severe pain, sudden vision loss, increasing redness, and discharge—seek care immediately if these occur.
Surgeon experience significantly impacts complication rates; choosing an experienced provider is one of the most important risk-reduction steps.
Educational information only
This content is general education and does not replace evaluation by a licensed clinician. If you have symptoms, complications, or urgent concerns, seek in-person medical care.
Understanding SMILE Complications: What Patients Should Know
Small Incision Lenticule Extraction (SMILE) is a flapless femtosecond laser-assisted refractive procedure that has been performed on millions of patients worldwide. As with any surgical procedure, understanding potential complications and their management is essential for anyone considering this vision correction option, particularly international travelers seeking care abroad [S1].
SMILE is generally considered safe and effective, with complication rates comparable to LASIK and PRK when performed by experienced surgeons. The overall incidence of complications that may affect final visual acuity is low, and most complications that do occur can be managed successfully with appropriate intervention. However, patients should understand that complications can occur, recognize warning signs, and know how to respond appropriately [S3].
Understanding complications also means recognizing that individual risk varies based on several factors. These include your specific eye anatomy, the surgeon's experience level, and how closely post-operative care instructions are followed. This guide covers the types of complications that may occur, how they are typically managed, and when to seek immediate medical attention. For broader context on vision correction options, explore our eye care resources and eye treatment options.
Comparing SMILE to Other Refractive Procedures
SMILE differs from LASIK in that it does not create a corneal flap, which eliminates flap-related complications. Compared to PRK, SMILE typically offers faster initial recovery. However, each procedure carries its own risk profile, and the best choice depends on individual circumstances and should be determined through consultation with a qualified ophthalmologist [S1].
Rates vary based on surgeon experience and patient factors. Individual risk may differ from published averages [S1][S2].
Intraoperative Complications: Managing Challenges During Surgery
Intraoperative complications occur during the procedure itself. The most common include suction loss, incision-related issues, and lenticule extraction difficulties. Understanding these challenges helps patients appreciate the importance of surgeon experience and proper technique [S1].
Suction Loss
Suction loss is one of the most significant intraoperative complications in SMILE, occurring when the suction ring that stabilizes the eye becomes disconnected during the laser phase. Reported incidence ranges from 0.5% to 6.38%, with higher rates typically seen during a surgeon's early experience period [S2]. Risk factors include conjunctival swelling (chemosis), higher cylindrical prescriptions, narrow eyelid anatomy, smaller corneal diameter, and patient movements such as lid squeezing.
Management depends on when the loss occurs during the procedure. If suction is lost during the early laser stages, the procedure may be recovered by re-docking the patient interface. However, if suction is lost after more than 10% of the posterior plane cut has been completed, the procedure typically cannot continue and must be abandoned. In such cases, conversion to an alternative procedure such as PRK or femto-LASIK may be necessary, either during the same session or in a later procedure [S1].
Incision Complications
Incision tears and related issues occur in approximately 1.8% to 9.57% of SMILE procedures [S2]. These complications are generally minor and do not typically result in permanent visual impairment. Management usually involves topical antibiotic gels and artificial tears during the healing period. Most incision-related complications heal without affecting the final visual outcome.
Cap perforation, which occurs in only 0.22% to 0.7% of cases, is similarly usually minor and heals with minimal scarring [S1].
Lenticule Extraction Challenges
Black spots or islands—areas where the laser did not fully separate the corneal tissue—occur in 0.33% to 11% of procedures [S1]. These are typically caused by water droplets or meibomian gland secretions that block laser photo-disruption. During lenticule extraction, the surgeon must carefully separate tissue manually in these areas, which requires additional skill and technique.
The opaque bubble layer, occurring in approximately 0.73% of cases, refers to gas bubbles that become trapped within the corneal tissue during laser use. This condition generally resolves spontaneously as the bubbles dissipate over time [S1].
Postoperative Complications: Recovery and Warning Signs
Postoperative complications develop after the procedure is complete and may appear immediately or days to weeks later. Most are manageable with appropriate treatment, and understanding what constitutes normal recovery versus concerning symptoms is essential [S3].
Early Postoperative Period (First Week)
Dry eye symptoms are common after SMILE but occur less frequently than after LASIK—approximately 56% of patients experience dry eye at one week post-op compared to 95% after LASIK [S1]. Symptoms typically return to baseline within three months and are usually managed with artificial tears. The lower dry eye incidence with SMILE is attributed to the absence of a corneal flap and the smaller incision size.
Diffuse Lamellar Keratitis (DLK), sometimes called "sands of Sahara," is a non-infectious inflammatory condition that typically presents 24 to 48 hours after surgery. Occurring in 0.45% to 2.17% of cases, DLK is managed with an intensive topical steroid regimen. In severe cases, interface irrigation may be necessary to remove inflammatory cells [S3].
Infectious keratitis, while rare at approximately 0.39% in large studies, is a serious complication requiring immediate intervention [S1]. Risk factors are similar to those for LASIK and include dry eye, blepharitis, immunocompromised states, and epithelial defects.
Delayed Complications (Weeks to Months)
Corneal ectasia—a progressive thinning and bulging of the cornea—is extremely rare after SMILE, with only seven cases reported in the literature [S1]. This condition is strongly associated with pre-existing abnormal corneal topography or subclinical keratoconus that was not detected during pre-operative screening.
Transient Light Sensitivity Syndrome (TLSS) is an uncommon condition characterized by photosensitivity occurring between two and eight weeks postoperatively, often with otherwise good visual acuity. The condition responds well to steroid treatment, and most patients experience complete resolution with appropriate therapy.
Retained lenticule fragments may occasionally remain after the initial procedure and may require a secondary intervention for removal.
When to Seek Emergency Care
Distinguishing normal recovery symptoms from complications requiring immediate attention is critical for patient safety. While most post-operative symptoms are mild and temporary, certain signs warrant prompt medical evaluation [S1].
Seek Immediate Care For
Severe pain not relieved by prescribed or over-the-counter medication
Sudden vision loss or significant decrease in visual acuity
Increasing redness combined with pus-like discharge
Worsening irritation that does not improve with recommended eye drops
Signs of infection including heat, swelling, or persistent discomfort
Normal Recovery Expectations
Understanding what constitutes typical post-operative healing helps reduce anxiety while ensuring complications are not overlooked. Blurry vision during the first 24 to 48 hours is expected as the cornea begins healing. Mild dryness, foreign body sensation, and slight irritation are common and typically improve within the first week.
Visual acuity gradually stabilizes over days to weeks, though full visual recovery may take several months in some cases. Fluctuations in vision during the healing process are normal and do not necessarily indicate a problem.
For International Patients
If you are traveling internationally for SMILE, ensure you have:
Clear documentation of your procedure and post-operative care instructions
Access to emergency eye care at your destination before returning home
A plan for follow-up appointments with your surgeon or a local ophthalmologist after departure
Contact information for your surgical facility in case questions arise during recovery
Medical travel requires particular attention to aftercare planning, as returning home with unresolved issues can complicate management. Our medical travel support team can help coordinate follow-up care and escalation planning. Discuss protocols with your provider before booking travel.
Reducing Your Risk: What Patients Can Do
While not all complications can be prevented, patients can take meaningful steps to minimize their risk. The most significant factor is choosing an experienced surgeon who has performed a high volume of SMILE procedures [S2].
Surgeon Selection Criteria
Surgeon experience matters significantly for SMILE outcomes. Most complications decrease substantially after a surgeon has completed 100 to 200 procedures, with the steepest learning curve occurring during the first 50 cases [S2]. When evaluating potential surgeons, inquire about their total SMILE experience volume, their specific complication rates, and how they manage complications when they occur.
Our ophthalmology team includes surgeons with extensive SMILE experience who track outcomes and complications transparently. Board certification, fellowship training in refractive surgery, and membership in professional organizations such as the European Society of Cataract and Refractive Surgeons (ESCRS) provide additional indicators of expertise.
Pre-Operative Screening
Comprehensive pre-operative evaluation helps identify patients at elevated risk for complications. Essential assessments include corneal topography to detect irregular astigmatism or early keratoconus, corneal thickness measurement to ensure adequate tissue for safe correction, and tear film evaluation to assess dry eye risk [S1].
Discuss your complete medical and ocular history with your surgeon, including any medications, previous eye surgeries, or chronic conditions that might affect healing or complication risk. Full disclosure enables appropriate risk assessment and informed decision-making.
Patient Preparation
Following pre-operative instructions carefully supports optimal outcomes. These may include discontinuing contact lens use for a specified period before evaluation, avoiding certain medications or supplements that increase bleeding risk, and arranging transportation for the day of surgery.
Understanding the procedure, including its benefits and potential risks, helps patients maintain realistic expectations and reduces anxiety that might affect cooperation during surgery [S3].
Making an Informed Decision About SMILE
Weighing the benefits of SMILE against its potential risks is essential for making a decision aligned with your vision correction goals and risk tolerance. The procedure offers advantages including flapless surgery, potentially faster initial recovery, and preserved corneal biomechanical strength compared to LASIK.
However, no surgical procedure is without risk, and complications can occur even with optimal surgical technique and patient selection [S1]. Understanding that individual outcomes may vary—and that your personal risk profile depends on unique anatomical and health factors—helps establish realistic expectations.
Questions to Ask Your Surgeon
How many SMILE procedures have you performed, and what is your complication rate?
What is my specific risk profile based on my eye examination results?
How do you manage complications if they occur during my procedure?
What follow-up care will I receive, and how is it coordinated for international patients?
What should I do if I experience concerning symptoms after I return home?
Our surgical facilities utilize advanced femtosecond laser technology and maintain protocols for managing complications effectively.
Balancing Benefits and Risks
SMILE has helped millions of patients achieve clearer vision without glasses or contact lenses. Most patients experience smooth recoveries and good visual outcomes. However, understanding potential complications and having a plan for managing them—if they occur—is part of making a truly informed decision about whether SMILE is right for you. This information is educational and does not replace personalized ophthalmology consultation.
The Path Forward
If you are considering SMILE and want to understand how this procedure fits your vision correction goals, the first step is a comprehensive evaluation with an experienced refractive surgeon. During consultation, you can discuss your specific risks, ask questions about complication management, and determine whether SMILE or an alternative procedure offers the best path forward for your individual needs.
Start Your Plan to schedule a consultation and receive personalized guidance based on your unique vision profile and goals. Our team will help you understand your options, answer questions about potential complications, and develop a treatment plan aligned with your needs.
