Long-Term Outcomes of 10-Minute Accelerated Corneal Cross-Linking on Structural, Topographic, and Tomographic Corneal...

To evaluate the long-term effects of accelerated corneal cross-linking (ACXL) in stabilizing progressive keratoconus (KC), as these effects remain unclear.

This 5-year longitudinal study included 49 eyes with progressive KC who underwent 10-min ACXL. Baseline and posttreatment assessments included uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), refractive error (sphere, cylinder, and spherical equivalent), corneal curvature indices (maximum keratometry [Kmax], flat keratometry [K1], steep keratometry [K2], and mean keratometry), corneal thickness, and corneal irregularity indices (index of height asymmetry [IHA], index of surface variance [ISV], and inferior-superior value [IS-value]). Corneal imaging was performed using Pentacam and Corvis ST. Longitudinal changes were analyzed using repeated-measures statistical models.

Significant improvements were observed in UCVA and BCVA over time (P = 0.001). Keratometric indices (K1, K2, and Kmax) initially declined, indicating corneal flattening, followed by a mild regression at later time points (P < 0.005). Corneal thickness (thinnest location) decreased transiently but stabilized by year 5 (P = 0.003). Corneal topographic indices revealed mixed trends: corneal densitometry increased progressively (P = 0.001), suggesting long-term structural changes. Corneal irregularity indices (IHA, ISV, IS-value, and index of vertical asymmetry) demonstrated initial fluctuations but overall improvement, reflecting enhanced corneal regularity (P < 0.05). Posterior radius of curvature initially increased, then decreased at year 5 (P = 0.016), indicating late risk for posterior corneal steepening. Progression indices (progression index max and IS-value) showed a downward trend, supporting disease stabilization (P = 0.028).

This study supports the long-term efficacy of 10-min ACXL in stabilizing progressive KC, with sustained improvements in corneal irregularity indices and visual function. Early 10-min ACXL intervention is recommended to be considered for maximizing stabilization and preventing advanced disease progression.