Abstract
BACKGROUND: This retrospective comparative cohort study aimed to compare the one-year outcomes of two modified surgical protocols, the Athens protocol followed by accelerated corneal cross-linking (ACXL) (topography-guided transepithelial photorefractive keratectomy [TG-TPRK] combined with ACXL) and the Cretan protocol followed by ACXL (transepithelial phototherapeutic keratectomy [TPTK] combined with ACXL), in patients with progressive keratoconus. METHODS: The study included 92 eyes of 67 patients (49 eyes/34 patients in the TG-TPRK-ACXL group; 43 eyes/33 patients in the TPTK-ACXL group). According to the TG-TPRK-ACXL ablation plan, TPTK was conducted on patients with a projected postoperative thinnest corneal thickness (TCT) of less than 400 μm. Visual acuity, refractive status, keratometry readings, corneal thickness, and keratoconus parameters were assessed preoperatively and 1-year postoperatively. Intraoperative ablation depth was also recorded. Generalized estimating equations (GEE) were applied to adjust for baseline characteristics and to compare the differences in ocular characteristic changes between the two groups after 1 year. RESULTS: Both groups showed significant improvement in uncorrected and best spectacle-corrected distance visual acuity (UDVA and BCVA) as well as a reduction in postoperative corneal curvature and irregularity index. After GEE correction, the TPTK-ACXL group showed a greater increase in BCVA (β = -0.117, P = 0.002). There were no significant variances between the two groups regarding changes in refractive error, corneal curvature, corneal astigmatism, and keratoconus parameters. Central and maximum ablation depths were thinner in the TPTK-ACXL group than in the TG-TPRK-ACXL group (P < 0.001). No serious intraoperative or postoperative complications were reported. CONCLUSIONS: Both TPTK-ACXL and TG-TPRK-ACXL treatments have demonstrated efficacy in improving visual acuity and corneal regularity among keratoconus patients at the 1-year follow-up. TPTK-ACXL may be particularly beneficial for patients with poorer corneal conditions, potentially minimizing corneal thickness loss and serving as a substitute for TG-TPRK-ACXL.