Comparing the Outcomes of Different Corneal Refractive Surgeries, Such as (Lasik) Laser Assisted in Situ Keratomileusis, (PRK) Photorefractive Keratectomy, and (Smile) Small Incision Lenticule Extraction

This literature review provides an in-depth analysis of visual outcomes, dry eye incidence, corneal sensitivity, and high-order aberrations (HOAs) associated with three common corneal refractive surgeries: Transepithelial Photorefractive Keratectomy (Trans-PRK), Laser-Assisted in Situ Keratomileusis (LASIK), and Small Incision Lenticule Extraction (SMILE). In terms of visual outcomes, Trans-PRK demonstrates favorable efficacy and safety comparable to LASIK, with potential advantages in predictability. However, Trans-PRK adult patients may experience higher variability in spherical equivalent during the postoperative period. Conversely, SMILE exhibits comparable visual outcomes to LASIK, but with delayed visual acuity recovery possibly due to stromal edema. Comparative studies between Trans-PRK and SMILE are limited, but initial findings suggest SMILE may offer improved visual results and reduced residual astigmatism. Dry eye and corneal sensitivity post-surgery vary among procedures, influenced by factors such as nerve damage, flap size, and ablation size. PRK results in severance of corneal nerves, leading to temporary postoperative pain, whereas LASIK and SMILE show differing rates of reinnervation, with SMILE potentially preserving corneal sensitivity better due to its less invasive nature. High-order aberrations, affecting visual quality, differ among surgeries. Trans-PRK is believed to induce fewer aberrations due to greater corneal integrity compared to LASIK, while SMILE may lead to higher levels of coma and total HOAs in the early postoperative period.