Laser vision correction has never been more advanced, more precise, or more accessible. Yet for many patients exploring freedom from glasses and contact lenses, the range of available procedures can feel confusing. LASIK, SMILE, PRK, Trans-PRK, femto-LASIK — what do these terms mean, how do they differ, and which one is the right choice?
This post, published by The Vision Surgeon, provides a clear and evidence-based breakdown of the three main categories of corneal laser vision correction. It is intended to help patients arrive at their consultation with Dr. Rylan Hayes already informed about the landscape, so that the conversation can focus on what matters most: determining which approach suits their individual eyes, lifestyle, and visual goals. Those who are not yet sure whether they are candidates can begin with the Glasses & Contacts Self-Assessment Quiz on the practice website.
How Laser Vision Correction Works: The Shared Principle
All three procedures share the same fundamental goal: to reshape the cornea so that light entering the eye focuses precisely on the retina without the need for glasses or contact lenses. The cornea contributes approximately two-thirds of the eye’s total focusing power, making it the ideal target for refractive correction.
The differences between the procedures lie in how the corneal stroma (the main structural layer of the cornea) is accessed and reshaped. Understanding this distinction is the key to understanding why one procedure may suit a particular patient better than another.
PRK and No-Touch Trans-PRK: Surface Laser Correction
How It Works
Photorefractive keratectomy (PRK) has been performed since the early 1990s. In standard PRK, the corneal epithelium — the thin surface layer of cells — is manually removed before the excimer laser reshapes the underlying stroma. The epithelium then regenerates over the following days.
No-Touch Trans-PRK is an advanced evolution of the technique in which the epithelium and stroma are treated in a single, fully contact-free laser step — without any manual removal or any instrument touching the eye. At The Vision Surgeon, Dr. Rylan Hayes can perform No-Touch Trans-PRK using the Schwind Amaris laser. More details on this specific approach are available on the Laser Vision Correction Surgery page.
Advantages of PRK/Trans-PRK
Because PRK/Trans-PRK does not create a corneal flap, it preserves significantly more corneal structural integrity than other techniques. This makes it the preferred option for:
- Patients with thinner corneas, where the residual stromal bed after LASIK would be insufficient
- Patients engaged in contact sports, martial arts, or occupations involving a risk of direct eye trauma — where a LASIK flap could theoretically be displaced.
- Patients with dry eye tendencies, as surface ablation disrupts fewer corneal nerves than LASIK
- Patients who may struggle to tolerate the procedure if instruments are required to touch the eye.
Long-term studies with follow-up periods exceeding 10 years have demonstrated that PRK carries a high level of safety with rare late complications. Regression — a partial return of the refractive error — is uncommon within the recommended treatment range.
Considerations
The trade-off for surface ablation is recovery time. Because the epithelium must regenerate, visual rehabilitation takes longer than with LASIK or SMILE — typically one to two weeks to functional vision, and up to two to three months for full optical stabilization. Temporary discomfort in the first few days post-operatively is common and is managed with pain relief drops and bandage contact lenses. There is also a small risk of corneal haze formation with higher corrections, though this risk is substantially mitigated by modern laser platforms and post-operative mitomycin C application when indicated.
LASIK: The Flap-Based Approach
How It Works
Laser in situ keratomileusis (LASIK) has been the dominant global refractive surgery procedure for three decades. A thin hinged flap of corneal tissue is created in modern practice with a femtosecond laser (femtosecond LASIK or FS-LASIK). The flap is lifted, the excimer laser reshapes the exposed stromal bed, and the flap is repositioned. Because the epithelium is preserved within the flap, healing is rapid.
Advantages of LASIK
- Fastest visual recovery of the three modalities — most patients achieve excellent vision within 24 hours
- Minimal post-operative discomfort compared to PRK
- Very high patient satisfaction rates, with extensive long-term outcome data
LASIK outcomes are well established. Studies with 10-year follow-up confirm high safety, predictability, and stability within the recommended correction range. Large comparative studies have found no statistically significant difference in visual acuity outcomes between LASIK, PRK, and SMILE at 6 and 12 months post-operatively — each achieving 20/20 or better in approximately 94–95% of eyes.
Considerations
The creation of a corneal flap introduces specific considerations:
- Flap-related complications, though rare, include incomplete flap creation, which may rarely require abandoning the procedure and completing with PRK either at the time or in a few months once healed.
- LASIK involves greater disruption of corneal biomechanics than the other two modalities, removing more stromal tissue and cutting more corneal nerves
- Dry eye symptoms in the first months post-operatively are more common with LASIK than with SMILE or PRK, due to greater corneal nerve disruption.
- Corneal ectasia — a rare but serious thinning and bulging of the cornea — is associated with LASIK when insufficient residual stromal bed thickness is left, making careful pre-operative screening critical.
SMILE: Flapless Corneal Lenticule Extraction
How It Works
Small incision lenticule extraction (SMILE) is the well known brand name for laser assisted lenticular extraction (LALEX) – the most recent of the three modalities, gaining global traction over the past decade. A femtosecond laser creates a precise lenticule — a disc-shaped sliver of corneal stroma — within the intact cornea. This lenticule is then removed through a small arc-shaped incision (typically 2–3mm) in the corneal surface. The removal of the lenticule changes the corneal curvature and corrects the refractive error. No flap is created, and the epithelium remains largely intact.
Advantages of SMILE
- Superior corneal biomechanical stability: because the anterior stroma, the strongest part of the cornea, is largely preserved, SMILE is theoretically associated with better biomechanical integrity than LASIK
- Less dry eye: studies consistently show fewer and less severe dry eye symptoms post-SMILE compared to LASIK, however it can still occur.
- Faster visual recovery than PRK, with most patients achieving functional vision within a few days
A randomized controlled trial comparing SMILE and femtosecond LASIK found no statistically significant differences in efficacy, predictability, or safety at 3 and 12 months. A 2024 meta-analysis of 17 randomized controlled trials confirmed that SMILE produces outcomes comparable to other corneal refractive surgeries in terms of efficacy, safety, stability, predictability, and higher-order aberrations.
Considerations
- Currently, it corrects some prescriptions of myopia and myopic astigmatism; hyperopic correction is not yet widely performed with SMILE.
- The long-term evidence base is less extensive than for LASIK or PRK, simply because it has a shorter clinical history.
- Retreatment, if required, is technically more complex than with LASIK.
How to Choose: Key Decision Factors
Corneal Thickness and Anatomy
Corneal thickness is one of the most important determinants of procedure selection. Thinner corneas may not have sufficient residual stromal bed for safe LASIK. PRK or SMILE, which removes or preserves more anterior tissue, respectively, may be more appropriate.
Degree of Correction Required
All three procedures can effectively correct mild to moderate myopia. For higher prescriptions, the choice of procedure and the calculations of residual corneal tissue become more critical, and these are assessed in detail during pre-operative corneal mapping.
Lifestyle and Occupation
Patients in contact sports (martial arts, rugby, boxing, surfing wipeouts) or occupations with risk of direct ocular trauma are often counseled toward PRK, given the absence of a flap.
Dry Eye Status
Patients with pre-existing dry eye disease are generally better candidates for PRK than for LASIK, as it produces less post-operative dry eye; however, it does not eliminate it. Pre-operative dry eye assessment and treatment are a standard part of the evaluation process at The Vision Surgeon.
Recovery Time Tolerance
Patients who cannot afford extended visual recovery — due to work demands or other commitments — may prefer LASIK. LASIK offers the fastest rehabilitation, followed by SMILE, with PRK requiring the longest recovery period.
What All Three Procedures Have in Common
Despite their differences, LASIK, SMILE, and PRK share several important features:
- Comparable final visual outcomes at 6–12 months: large comparative studies and meta-analyses have found no clinically significant differences in ultimate visual acuity between the three procedures in appropriately selected patients
- High safety profiles: all three are among the most studied elective surgical procedures in medicine, with decades of peer-reviewed outcome data. SMILE has less longevity of data.
- Long-term stability within the recommended treatment range: regression is uncommon and mild when it does occur
- A requirement for stable refraction before surgery: the refractive error must not have been changing for at least 12 months prior to surgery
The Role of a Pre-Operative Assessment
No blog post can determine which procedure is right for a specific patient. Individual corneal anatomy, topography, pachymetry (thickness mapping), tear film quality, pupil size, and refraction all contribute to the decision. This is the purpose of the pre-operative assessment.
At The Vision Surgeon, Dr. Rylan Hayes works alongside the in-house optometry team at LaserSight Maroochydore to provide comprehensive corneal assessment prior to any laser vision correction procedure. A free eligibility assessment is available for patients considering laser vision correction or refractive lens exchange. This includes detailed corneal scanning and an optometric workup, enabling an informed discussion with Dr. Hayes about the most suitable procedure for each patient’s eyes and lifestyle.
⚠️ All surgery carries risk. Your individual risk/benefit profile can only be discussed in person.
* Free eligibility covers initial scans and screening with in-house optometrists. The T&C on the website do not include any consultation with a surgeon or any treatment procedures.
References
- Taneri S, et al. Long-term outcomes of PRK, LASIK, and SMILE. Ophthalmologe. 2022;119(2):163-169. PMID:34241701.
- Ang M, et al. Randomized clinical trial comparing femtosecond LASIK and SMILE. Ophthalmology. 2020;127(6):724-730. PMID:31619358.
- Ryan DS, et al. Quality of vision and patient satisfaction after refractive surgery: LASIK, SMILE, and PRK. J Spec Oper Med. 2025;24(4):86-92. PMID:39641610.
- Sia RK, et al. Visual outcomes after SMILE from the first-year experience at a US military refractive surgery center. J Cataract Refract Surg. 2020;46(7):995-1002. PMID:32271272.
- Chen W, et al. Comparison of clinical outcomes of LASIK, Trans-PRK, and SMILE for correction of myopia. Chin Med J. 2022. PMC12755589.
- Hira S, et al. Comparison of refractive surgeries (SMILE, LASIK, and PRK) with and without corneal crosslinking: systematic review and meta-analysis. J Cataract Refract Surg. 2024;50(5):523-533. PMID:38288954.
- Ji Y, et al. Analysis of the effectiveness of SMILE, FS-LASIK, and SBK in myopic patients. Contrast Media Mol Imaging. 2022. PMC9357722.
