Transepithelial Photorefractive Keratectomy (Trans-Prk) In Thin Corneas: A Retrospective Study Of 45 Patients

To evaluate the efficacy, safety, and long-term corneal stability of transepithelial photorefractive keratectomy (Trans-PRK) in patients with thin corneas (central pachymetry <500 µm).

This retrospective observational study analyzed patient records over a 2 years follow-up period at the Refractive Surgery Unit of the Military University Hospital of Constantine, Algeria.

This retrospective study included 45 patients (83 eyes) undergoing Trans-PRK between June 2022 and January 2023. Inclusion criteria comprised preoperative corneal thickness <500 µm (Pentacam topography), ≥2-year follow-up, and no concurrent ocular pathology. Surgical ablation was performed using the Schwind Amaris 750S® laser, with personalized refractive and topographic parameters. Postoperative assessments included uncorrected visual acuity (UCVA), corneal pachymetry, topography (Belin/Ambrósio indices for ectasia), and complications at 6 months, 1 year, and 2 years.

 Mean preoperative corneal thickness was 482 ±14 µm, with a myopic correction of -4.25 ±1.5 D. At 2 years, 85% of eyes achieved UCVA ≥8/10 (vs. 22% preoperatively, *p*<0.001), with a residual refraction of -0.25 ±0.5 D. Postoperative pachymetry remained stable (398 ±22 µm at 6 months vs. 395 ±20 µm at 2 years, *p*=0.12), and no ectasia or keratoconus was observed. Transient complications included grade 0.5 corneal haze (9.6% of eyes) and dry eye (26.7% of patients), both resolving with treatment.

Trans-PRK demonstrates high efficacy and safety in thin corneas, providing predictable refractive outcomes and long-term corneal stability without inducing ectasia. Its non-flap approach offers a viable alternative to LASIK for patients with biomechanical risk factors. Further prospective studies are warranted to validate these findings and refine patient selection criteria.