Long-Term Outcomes And Regularization Index Changes In Patients With Keratoconus After Accelerated Corneal Cross-Linking

To evaluate long-term keratometric changes of accelerated corneal crosslinking (A-CXL) in patients with keratoconus.

Marmara University, School of Medicine, Department of Ophthalmology

Ninety-eight eyes of 78 patients with keratoconus received A-CXL (9 mW/cm² irradiance for 10 minutes) were enrolled in this study. Best corrected distance visual acuity (BCVA) and keratometric values (K₁, K₂, Kmean, K_max,) were recorded. The regularization index (RI) was calculated from the Scheimpflug tomography by moving the computer cursor over each difference map to record the maximum steepening and flattening values. Last visit measurements were compared with baseline values.

The mean age of the patients was 22.5 ± 3.4 years (Mean follow-up: 2.7 ± 1.9 years). The mean Kmax and the Kmean were significantly decreased from preoperative (55.04 ± 5.65, 46.47 ± 3.20, respectively) to the last visit (54.15 ± 5.85, 45.75 ± 3.47, respectively) (p<0.001). There were no significant differences in K1 and K2 values (p=0.126, p=0.321, respectively). BCVA remained stable (Baseline; 0.29 ± 0.21 logMAR, Last visit; 0.28 ± 0.22 logMAR, p= 0.092). In 96.9% of patients, keratoconus regressed (42.7%) or stabilized (54.2%) after A-CXL. The mean RI was 2.90 ± 1.36 in stable eyes, 3.8 ± 2.10 in regressed eyes and 5.03 ± 1.26 in progressive eyes. RI was significantly correlated with the baseline Kmax value (r=0.358, p=0.001).

The A-CXL treatment demonstrates effectiveness in stabilizing the progression of keratoconus. Additionally, the preoperative Kmax appears to have the potential to serve as a predictive factor for the RI after A-CXL.