Clinical Outcomes of SMILE, FS-LASIK, and Trans-PRK for Myopia Correction in Iraq
Overview
This multicenter study in Iraq compared SMILE, FS-LASIK, and Trans-PRK for myopia correction, demonstrating that SMILE offers superior refractive predictability, long-term stability, and ocular surface outcomes. FS-LASIK showed intermediate results, while Trans-PRK was associated with greater residual myopia and higher enhancement rates.
Background
Myopia is a prevalent refractive error with increasing global incidence and associated risks such as retinal degeneration and glaucoma. Laser refractive surgeries, including FS-LASIK, SMILE, and Trans-PRK, have evolved to address myopia correction with varying techniques and outcomes. FS-LASIK involves flap creation and excimer laser ablation, SMILE is a flapless lenticule extraction method preserving corneal biomechanics, and Trans-PRK is a single-step surface ablation technique avoiding flap-related complications. Comparative data on these procedures guide optimal patient selection to maximize safety and visual outcomes.
Data Highlights
Procedure
Number of Eyes
Refractive Predictability
Residual Myopia
Induced HOAs
OSDI Scores
Safety Profile
SMILE
388
Highest, closest to emmetropia
Lowest residual myopia
Lowest
Lowest
High, low CDVA loss
FS-LASIK
344
Intermediate
Moderate residual myopia
Intermediate
Intermediate
High, low CDVA loss
Trans-PRK
187
Lowest predictability
Greatest residual myopia and regression
Highest
Highest
High, higher enhancement rates
Key Findings
SMILE demonstrated superior refractive predictability and long-term stability with postoperative spherical equivalent closest to emmetropia.
FS-LASIK showed intermediate refractive outcomes and ocular surface parameters between SMILE and Trans-PRK.
Trans-PRK was associated with greater residual myopia, increased refractive regression, and higher enhancement rates, especially in high myopia cases.
Induced corneal higher-order aberrations were lowest after SMILE and highest after Trans-PRK.
Ocular Surface Disease Index scores were consistently lowest following SMILE, indicating better ocular surface comfort.
All procedures exhibited high safety profiles with low rates of corrected distance visual acuity loss and infrequent need for enhancements.
Clinical Implications
SMILE should be considered the preferred surgical option for myopia correction due to its superior refractive accuracy, stability, and better ocular surface outcomes. FS-LASIK remains a viable and safe alternative for patients where SMILE is not suitable. Trans-PRK may be reserved for patients with contraindications to flap creation but requires counseling regarding slower visual recovery and higher likelihood of refractive regression.
Conclusion
In this large Iraqi cohort, SMILE outperformed FS-LASIK and Trans-PRK in refractive predictability, stability, and ocular surface health, supporting its use as a first-line refractive surgery for myopia. Procedure-specific patient selection is essential to optimize outcomes and postoperative comfort.
References
Iraqi Multicenter Study 2026 -- Clinical Outcomes of SMILE, Femtosecond LASIK, and Transepithelial PRK
