Customized Corneal Cross-linking: One-Year Results

Abstract

To compare the efficacy of customized corneal cross-linking (CXL) with standard CXL. Prospective, nonrandomized comparative clinical study. In a prospective study at the Institut für Refraktive und Ophthalmo-Chirurgie (IROC), Zurich, Switzerland, 40 eyes of 40 patients with documented progressive primary keratoconus were treated with customized CXL (n= 20) or standard CXL (n= 20) and followed for 1 year. Customized irradiation patterns had an energy fluence of 9 mW/cm(2) and total energy levels ranging from 5.4 J/cm(2) up to 10 J/cm(2) and were centered on the maximum of the posterior float. The control group received homogenous irradiation with a fluence of 9 mW/cm(2) and a total energy of 5.4 J/cm(2). Scheimpflug tomographies, endothelium cell count, best spectacle-corrected visual acuity (BSCVA), and anterior segment optical coherence tomography (OCT) were compared preoperatively and 1 year postoperatively. Pachymetry and ΔKmax showed significant changes 1 year postoperatively within each group. Epithelial healing time, ΔKmax, and regularization index (RI) were significantly better in the customized CXL group. Two out of 19 eyes (11%) in the standard group but 7 out of 19 eyes (37%) in the customized CXL group showed a flattening of 2 or more diopters (P= .03). The RI was 5.2 ± 2.7 D in the customized group vs 4.1 ± 3.1 D in the control group (P= .03). Statistically significant correlations between RI and preoperative Kmax, preoperative pachymetry, and preoperative posterior float were found only in the customized group. Customized CXL seems to be as safe as standard CXL with stronger flattening in Kmax and RI, and a faster epithelial healing period.