Predictors Of Treatment Success Following The Tel-Aviv Protocol For Keratoconus: A Combined Epithelial Photorefractive Keratectomy And Corneal Cross-Linking Approach

To identify preoperative predictors of treatment success following the Tel-Aviv Protocol, a combined epithelial photorefractive keratectomy (ePRK) and corneal cross-linking (CXL) procedure for progressive keratoconus.

Retrospective Study, Care-Vision Laser Center, Tel Aviv, Israel

This retrospective study evaluated patients with progressive keratoconus who underwent the Tel-Aviv Protocol (50-µm laser epithelial ablation + 50% astigmatism correction + CXL). Treatment success was defined by 9 measures: Efficacy and Safety Indices >1, improvement in UCVA or BCVA (≥1 or ≥2 rows), and decreased severity via the General Severity Markers (GSM), Collaborative Longitudinal Evaluation of Keratoconus (CLEK), and Amsler–Krumeich (AK) grading systems. Univariable screening followed by multivariable binary logistic regression was performed to identify independent preoperative predictors, including age, sex, visual acuity, spherical equivalent, pachymetry, keratometric parameters, and severity indices.

Multivariable regression analysis demonstrated that preoperative BCVA was an independent predictor across visual outcome indices. Patients with better baseline vision showed lower odds for Efficacy Index>1 (OR=0.033), Safety Index>1 (OR=0.011), and BCVA gains of ≥1 (OR=0.009) or ≥2 lines (OR=0.006). Steeper baseline Kmax predicted lower odds of a Safety Index>1 (OR=0.825) and visual gains (OR=0.785–0.717). Regarding severity scores, greater baseline myopia, reflected by a lower negative spherical equivalent (SEQ), predicted improvement in GSM and AK scores, while thinner corneas were associated with GSM improvement. Demographic factors, including age and sex, were not statistically significant predictors in any of the multivariable models.

Preoperative visual acuity is the strongest and most consistent predictor of treatment success following the Tel-Aviv Protocol across multiple outcome definitions. Patients with poorer baseline BCVA, flatter Kmax, and greater myopia demonstrate higher odds of achieving clinically meaningful improvement, reflecting greater capacity for therapeutic benefit. These findings may guide patient counseling and expectation management prior to ePRK-CXL.