Clinical Outcomes of Repeated Corneal Crosslinking for Progressive Keratoconus After Failure of Primary Procedure; Safety and Efficacy at 12-Month Follow-Up.

INTRODUCTION

This study aims to evaluate the efficacy and safety of repeated corneal cross-linking (CXL) in patients with progressive keratoconus who have undergone an unsuccessful primary epithelium-off (epi-off) CXL procedure. Additionally, it compares the keratometric changes between initial and repeated CXL treatments.

METHODS

In this multicenter retrospective cohort study, eyes that underwent repeated accelerated epi-off CXL (9 mW/cm2 for 10 min) were compared to eyes that received only a single successful procedure. Keratometric values (Kmax, K1, K2), thinnest corneal point, and corrected distance visual acuity (CDVA) were assessed preoperatively and at 12 months postoperatively.

RESULTS

Fifty-three eyes from 53 patients were included (26 repeated CXL, 27 control). In the control group, Kmax decreased by a median of 0.90 D (from 56.3 to 55.5 D, p = 0.0092) and the thinnest point increased by a mean of 35 µm (p = 0.001). In the repeated CXL group, Kmax decreased by 0.10 D (from 60.8 to 59.1 D, p = 0.307), and the thinnest point remained stable (436 to 435 µm, p = 0.8728). CDVA did not change significantly in either group. No complications were observed.

CONCLUSIONS

Repeated accelerated CXL appears to be a safe and effective option for stabilizing keratoconus after failure of the primary procedure. While the corneal flattening effect was milder compared to primary CXL, disease progression was halted in all eyes following retreatment.